Novel Er3+-doped bismuth lead strontiam glass was fabricated and characterized, and the absorption spectrum and upconversion spectrum of the glass were studied. The Judd-Ofelt intensity parameters Ωt (t=2, 4, 6) were...Novel Er3+-doped bismuth lead strontiam glass was fabricated and characterized, and the absorption spectrum and upconversion spectrum of the glass were studied. The Judd-Ofelt intensity parameters Ωt (t=2, 4, 6) were found to be Ω2=3.27×10-20 cm2, Ω4=1.15×10-20 cm2, and Ω6=0.38×10-20 cm2. The oscillator strength, the spontaneous transition probabilities, the fluorescence branching ratios, and excited state lifetimes were also measured and calculated. The upconversion emission intensity varies with the power of infrared excitation intensity. A plot of log Iup vs log IIR yields a straight line with slope 1.86, 1.88 and 1.85, corresponding to 525, 546, and 657 nm emission bands, respectively, which indicates that a two-photon process for the red and green emission.展开更多
All-vanadium flow batteries(VFBs)are one of the most promising large-scale energy storage technologies.Conducting an operando quantitative analysis of the polarizations in VFBs under different conditions is essential ...All-vanadium flow batteries(VFBs)are one of the most promising large-scale energy storage technologies.Conducting an operando quantitative analysis of the polarizations in VFBs under different conditions is essential for developing high power density batteries.Here,we employ an operando decoupling method to quantitatively analyze the polarizations in each electrochemical and chemical reaction of VFBs under different catalytic conditions.Results show that the reduction reaction of V^(3+)presents the largest activation polarization,while the reduction reaction of VO_(2)^(+)primarily contributes to concentration polarizations due to the formation of the intermediate product V_(2)O_(3)^(3+).Additionally,it is found that the widely used electrode catalytic methods,incorporating oxygen functional groups and electrodepositing Bi,not only enhance the reaction kinetics but also exacerbate concentration polarizations simultaneously,especially during the discharge process.Specifically,in the battery with the high oxygen-containing electrodes,the negative side still accounts for the majority of activation loss(75.3%)at 200 mA cm^(-2),but it comes down to 36,9% after catalyzing the negative reactions with bismuth.This work provides an effective way to probe the limiting steps in flow batteries under various working conditions and offers insights for effectively enhancing battery performance for future developments.展开更多
Owing to their low toxicity and remarkable stability, perovskites based on antimony and bismuth have garnered significant interest in recent years. However, A_(3)B_(2)X_(9) perovskite materials derived from antimony a...Owing to their low toxicity and remarkable stability, perovskites based on antimony and bismuth have garnered significant interest in recent years. However, A_(3)B_(2)X_(9) perovskite materials derived from antimony and bismuth face several challenges, including excessively wide band gaps, elevated defect densities, and suboptimal film quality, all of which hinder advancements in device efficiency. While extensive studies have been undertaken to investigate the effects of modulating the A-site and X-site elements in lead-free A_(3)B_(2)X_(9) perovskites, there remains a notable scarcity of reports addressing the impact of modifications to the B-site element. In this study, we investigated the alloying of antimony and bismuth within the 2D Cs_(3)B_(2)I_(6)Br_(3) perovskite. By systematically varying the ratios of two elements, we found that the incorporation of both antimony and bismuth at the B-site significantly enhances the quality of the perovskite films. Our findings indicate that a 1 : 1 ratio of antimony to bismuth produces the densest films, the highest photoluminescence intensity, and superior photovoltaic performance. Ultimately,the devices fabricated using this optimal ratio achieved an open-circuit voltage(VOC) of 1.01 V and a power conversion efficiency(PCE) of 0.645%.展开更多
The technology of solid-state lighting has developed for decades in various industries.Phosphor,as an element part,determines the application domain of lighting products.For instance,blue and redemitting phosphors are...The technology of solid-state lighting has developed for decades in various industries.Phosphor,as an element part,determines the application domain of lighting products.For instance,blue and redemitting phosphors are required in the process of plant supplementing light,arrow-band emitting phosphors are applied to backlight displays,etc.In this work,a Bi^(3+)-activated blue phosphor was obtained in a symmetrical and co mpact crystal structure of Gd3Sb07(GSO).Then,the co-doping strategy of alkali metal ions(Li^(+),Na^(+),and K^(+))was used to optimize the performance.The result shows that the photoluminescence intensity is increased by 2.1 times and 1.3 times respectively by introducing Li~+and K^(+)ions.Not only that,it also achieves narrow-band emitting with the full width of half-maximum(FWHM)reaching 42 nm through Na^(+)doping,and its excitation peak position also shifts from 322 to 375 nm,which can be well excited by near-ultraviolet(NUV)light emitting diode(LED)chips(365 nm).Meanwhile,the electroluminescence spectrum of GSO:0.6 mol%Bi^(3+),3 wt%Na^(+)matches up to 93.39%of the blue part of the absorption spectrum of chlorophyll a.In summary,the Bi^(3+)-activated blue phosphor reported in this work can synchronously meet the requirements of plant light replenishment and field emission displays.展开更多
Solving the problems of carbon dioxide(CO_(2))emissions and energy scarcity by the development of highly selective,cost-effective,and reliable catalysts for the electrochemical reduction of CO_(2)to useful carbon-base...Solving the problems of carbon dioxide(CO_(2))emissions and energy scarcity by the development of highly selective,cost-effective,and reliable catalysts for the electrochemical reduction of CO_(2)to useful carbon-based products would be very helpful.We report the synthesis of an efficient graphene-supported bismuth single-atom catalyst(BiSA-G)featuring a BiN_(4)coordination structure for this purpose.The synthesis used tannic acid as a multifunctional ligand and ammonia as a nitrogen dopant.Using a scalable coordination chemistry approach,BiN_(4)sites were uniformly dispersed on the graphene substrate and were found to have an outstanding ability for the conversion of CO_(2)to CO,with a high Faradaic efficiency of 97.4%at−0.55 V(vs.RHE)and a high turnover frequency of 5230 h^(−1)along with outstanding stability.Density functional theory calculations confirmed that the BiN_(4)site serves as the dominant active center,simultaneously facilitating CO_(2)activation and the efficient formation of the crucial intermediate*COOH with a reduced free energy barrier.This discovery offers a new way for the atomic-scale design of high-efficiency catalysts for the electrochemical CO_(2)reduction reaction,potentially helping sustainable carbon use.展开更多
Iron(Fe)nanoparticles and graphite(Gr)with different masses of bismuth trisulfide(Bi_(2)S_(3))were mixed by high-energy ball milling treatment to fabricate the corresponding composite iron anodes Bi_(2)S_(3)@Fe-Gr.The...Iron(Fe)nanoparticles and graphite(Gr)with different masses of bismuth trisulfide(Bi_(2)S_(3))were mixed by high-energy ball milling treatment to fabricate the corresponding composite iron anodes Bi_(2)S_(3)@Fe-Gr.The hydrogen evolution reaction and iron passivation process on these iron electrodes were investigated in alkaline and neutral solutions.The iron electrode Bi_(2)S_(3)-3@Fe-Gr(The additional amount of Bi_(2)S_(3)was 3 mg)revealed the strongest ability to inhibit hydrogen evolution among the iron electrodes of the present investigation,while the Bi_(2)S_(3)-6@Fe-Gr electrode(The additional amount of Bi_(2)S_(3)was 6 mg)delivered significant performance in inhibiting anodic passivation.This is because the high-energy ball milling process leads to the well-dispersion of Bi_(2)S_(3)and the changes in the surface of Fe nanoparticles,thereby slowing down the passivation of the iron electrode surface.展开更多
Introduction Pure NBT exhibits the frequency-dependent Curie temperature,indicating that its dielectric properties are affected by temperature,measurement frequency,and material processing condition.To enhance the die...Introduction Pure NBT exhibits the frequency-dependent Curie temperature,indicating that its dielectric properties are affected by temperature,measurement frequency,and material processing condition.To enhance the dielectric and relaxor properties of NBT,various dopants such as Sr,K,Li and Bi are incorporated into the NBT structure.These modifications significantly alter the dielectric constant and relaxation behavior,demonstrating a dominant influence of dopant on the material properties.Among these,the solid solution of BaTiO_(3)(BT)with NBT is widely investigated due to its ability to stabilize the perovskite structure and improve dielectric performance.However,the temperature-dependent stability of dielectric properties remains a critical challenge for high-temperature applications.In this study,(1-x)(0.75Na_(0.5)Bi_(0.5)TiO_(3)-0.25BaTiO_(3))-xBaZrO_(3)(NBT-BT-xBZ,x=0,0.08,0.14,and 0.20)ceramics were prepared by a solid-state reaction method.The effect of BaZrO_(3)(BZ)addition on the structural,dielectric,and energy storage properties was systematically investigated.In addition,the phase transition and relaxation behaviors were also analyzed based on the modified Curie-Weiss law,Vogel-Fulcher relation,and Lorentz-type empirical law.Methods The starting materials were powders of high purity Na_(2)CO_(3),Bi_(2)O_(3),TiO_(2),BaCO_(3),and ZrO_(2).The powders were weighed according to a stoichiometric ratio(with 1%excess of Na and Bi)and ground with ethanol in a ball mill at 300 r/min for more than 12 h,and the weight ratio of raw material to ethanol and zirconium balls was 1:1:2.The dried material was heat-treated at 850℃ for 2 h to promote the formation of NBT-BT-BZ.After further grinding for 12 h,the samples were mixed with a small amount of polyvinyl alcohol(PVA).The samples were sintered in air at 1150℃for 2 h and cooled to room temperature.The phase composition of the ceramic samples was determined by an model D8 ADVANDCE X-ray diffractometer(D8 ADVANDCEXRD,Bruker AXS Ltd.,Germany)with Cu target Kαrays,at X-ray wavelengthλof 1.5406Å,2θin the range of 10°to 80°,applied voltage of 40 kV,and a current of 500 mA.A silver paste was coated on the two surfaces as electrodes and heat-treated at 700℃ for 10 min.The dielectric properties of the ceramic samples were determined at different frequencies by a model DMS-1000 high-temperature dielectric temperature spectroscope(BALAB Tech.Co.,China)with at a ramp rate of 3(°)/min in a temperature range from room temperature to 450℃.The overdamped(200Ω)discharge tests for bulk ceramic samples were performed by a model CFD-005 discharge tester(Gogo(GG)Instruments Technology,China)).Results and discussion The XRD patterns indicate that all the ceramic samples have a perovskite structure without any detectable secondary phase,proving that zirconium ions can completely enter the lattice and form a solid solution.Based on the locally magnified XRD peaks,the XRD peak shape shifts towards lower angles as a whole as the BZ content increases.This indicates that the overall volume of the crystal cell shows an expansion as the Zr ions replace Ti ions due to different ionic radii of Zr and Ti ions.The SEM images show that the grain size gradually increases with increasing the BZ content.The addition of BZ promotes the grain growth.However,this gradually slows down with the increase of content up to x of 0.20.The limited grain size variation appears in the latter two samples.All the samples show a relatively dense morphology.The Curie temperature of the NBT-0.25BT ceramic samples is 256℃,which is similar to the reported results.The Curie temperature decreases gradually with the increase of BZ additive,and the dielectric temperature spectrum flattens out,indicating that the enhanced structural and temperature stability of the NBT-BT-BZ ceramics.The maximum values of all dielectric constants correspond to temperatures that increase with frequency,indicating a dielectric relaxor behavior.A frequency dispersion is accompanied at near the Curie temperature,which can be ascribed to the thermal evolution of the tetragonal polar nanoregions(PNRs)and the mixing effect of the transition from tripartite to tetragonal PNRs.Theγvalues obtained from the experimental data at 100 kHz are 1.79,1.83,1.89,and 1.92 for NBT-BT,NBT-BT-0.08BZ,NBT-BT-0.14BZ,and NBT-BT-0.20BZ,respectively.Theγvalue increases gradually with the addition of the BZ content,showing an enhanced relaxation of the NBT-BT-BZ ceramics.The comparison of discharge current curves and energy density of all the ceramics indicate that the addition of BZ significantly improves the discharge current and energy storage performance.A high discharging energy density(Wd)of 1.6 J·cm^(-3) with a fast discharging speed(τ0.9)of 75 ns is obtained for the ceramic samples with x of 0.14.This can be attributed to an increased relaxation as the BZ content increases.Conclusions NBT-BT-BZ ceramics were prepared by a solid-state reaction method.The XRD patterns revealed a phase transition from a tetragonal phase to a pseudocubic phase as the BZ content increased.The dielectric relaxation behavior of the ceramics could be described by three empirical laws(i.e.,modified Curie-Weiss law,Vogel-Fulcher relation and Lorentz-type empirical law).The dielectric relaxation followed the modified Curie-Weiss law and the Vogel-Fulcher relationship.The parametersγand Ea,which were obtained to evaluate the relaxation behavior,increased at a higher BZ content.The Lorentz-type relationship effectively described the temperature dependence of the dielectric constant on both the low-and high-temperature sides within a specific temperature range for all the ceramics.展开更多
High-temperature piezoelectric vibration sensors are the preferred choice for structural health monitoring in harsh environments such as high temperatures and complex vibrations.Bismuth layer-structured CaBi_(4)Ti_(4)...High-temperature piezoelectric vibration sensors are the preferred choice for structural health monitoring in harsh environments such as high temperatures and complex vibrations.Bismuth layer-structured CaBi_(4)Ti_(4)O_(15)(CBT)high-temperature piezoelectric ceramics,with high Curie temperature(TC),are the key components for piezoelectric vibration sensors operating at temperatures exceeding 500℃.However,their low piezoelectric coefficient(d_(33))greatly limits their high-temperature applications.In this work,a novel Bi^(3+)self-doping strategy was employed to enhance the piezoelectric performance of CBT ceramics.The enhancement is attributed to an increase in the number of grain boundaries,providing more sites for space charge accumulation and promoting formation of space charge polarization.Furthermore,given that space charge polarization predominantly occurs at low frequencies,dielectric temperature spectra at different frequencies were used to elucidate the mechanism by which space charge polarization enhances piezoelectric properties of CBT ceramics.Excellent overall performance was achieved for the CBT-based high-temperature piezoelectric ceramics.Among them,TC reached 778℃,d_(33) increased by more than 30%,reaching 20.1 pC/N,and the electrical resistivity improved by one order of magnitude(reaching 6.33×10^(6)Ω·cm at 500℃).These advancements provide a key functional material with excellent performance for practical applications of piezoelectric vibration sensors at 500℃and above.展开更多
A recent paper published in Journal of the American Chemical Society by W.Zhang and co-workers reported a ground-breaking advance by establishing 209 Bi and 127 I ultra-wideline solid-state NMR(UW SSNMR)as powerful to...A recent paper published in Journal of the American Chemical Society by W.Zhang and co-workers reported a ground-breaking advance by establishing 209 Bi and 127 I ultra-wideline solid-state NMR(UW SSNMR)as powerful tools for probing bismuth and iodine ions in metal-organic frameworks(MOFs),despite the severe challenges associated with their exceptionally large quadrupolar interactions,and enabled the elucidation of key structural features that are otherwise difficult to access[1].展开更多
The competition between dimensionality and ordering in multiferroic materials is of great interest for both fundamental physics and potential applications. Combining first-principles calculations with micromagnetic si...The competition between dimensionality and ordering in multiferroic materials is of great interest for both fundamental physics and potential applications. Combining first-principles calculations with micromagnetic simulations, we investigate recently synthesized ultrathin perovskite bismuth ferrite(BFO) films. Our numerical results reveal that, at the monolayer limit, the ferroelectricity of BFO is missing because the octahedral distortions are constrained. However, the monolayer bismuth ferrite is a topological antiferromagnetic metal with tunable bimeron magnetic structure. The dual topologically non-trivial characteristics make monolayer bismuth ferrite a multifunctional building block in future spintronic devices.展开更多
Traditional pyrometallurgical and hydrometallurgical methods to extract bismuth from sulfide ores face problems such as high cost,low-concentration SO_(2)generation,and long process time.In this study,the cyclone tech...Traditional pyrometallurgical and hydrometallurgical methods to extract bismuth from sulfide ores face problems such as high cost,low-concentration SO_(2)generation,and long process time.In this study,the cyclone technology and slurry electrolysis method were combined.The bismuth sulfide ore was dissolved directly at the anode,while the high purity bismuth was deposited efficiently at the cathode under the advantages of the two methods.The short process and high-efficiency extraction of bismuth sulfide ore were realized,and the pollution of low-concentration SO_(2)was avoided.Then,the effects of several crucial experimental conditions(current density,reaction time,temperature,pH,liquid-solid ratio,and circulation flow rate)on the leaching efficiency and recovery efficiency of bismuth were investigated.The leaching and electrowinning mechanisms during the recovery process were also analyzed according to the research results of this paper to better understand the cyclone slurry electrolysis process.The experimental results showed that 95.19%bismuth was leached into the acid solution in the anode area under optimal conditions,and the recovery efficiency and purity of bismuth on the cathode reached 91.13%and 99.26%,respectively,which were better than those by the traditional hydrometallurgy recovery process.展开更多
The piezocatalytic characteristic of bismuth oxyhalides(BiOX,X=Cl,Br,and I) has been increasingly capturing interest for its potential in hydrogen evolution reaction(HER) through water splitting process.The performanc...The piezocatalytic characteristic of bismuth oxyhalides(BiOX,X=Cl,Br,and I) has been increasingly capturing interest for its potential in hydrogen evolution reaction(HER) through water splitting process.The performance regarding these piezocatalysts is closely related to the halogen element present in BiOX;yet,the specific influence mechanisms remain unclear.In this study,we prepared BiOX catalysts via a hydrothermal process and explored their piezocatalytic HER activities.Owing to the layered bismuth s tructure,the resulting sheet-like piezocatalysts can efficiently capture the mechanic stimulus and allow the robust piezoelectric field,contributing to the piezocatalytic operation.It demonstrates that the BiOBr achieves a remarkable piezocatalytic HER efficiency of 813 μmol g^(-1)h^(-1),outperforming BiOCl and BiOI.The density functional theory(DFT)calculation results reveal that the BiOBr with moderate halogen atom size and lattice layer spacing possesses the strongest piezoelectricity,which enhances the separation and transfer of electron-hole pairs.Meanwhile,the exposed Br atom layer facilitates a large Bader charge and a low surface Gibbs free energy(ΔG_(H)),enhancing charge transfer for hydrogen reduction at the solid-liquid surface,thereby increasing the HER efficiency.This research sheds light on the halogen-dependent piezocatalytic activity of BiOX catalysts,offering valuable insights for the development of high-performance piezocatalysts.展开更多
The bismuth-telluride-based alloy is the only thermoelectric material commercialized for the applications of refrigeration and energy harvesting,but its low cost-effectiveness severely restricts its large-scale ap-pli...The bismuth-telluride-based alloy is the only thermoelectric material commercialized for the applications of refrigeration and energy harvesting,but its low cost-effectiveness severely restricts its large-scale ap-plication.The introduction of a porous structure in bulk thermoelectric materials has been theoretically proven to effectively reduce thermal conductivity and cost.However,the electrical properties of highly porous materials are considerably suppressed due to the strong carrier scattering at the interface be-tween the matrix and pores,ultimately leading to decreased figure of merit,ZT.Here,we use an atomic layer deposition strategy to introduce some hollow glass bubbles with nano-oxide layers into commercial Bi_(0.5)Sb_(1.5)Te_(3)for preparing high-performance porous thermoelectric materials.Experimental results indi-cate that the nano-oxide layers weaken carrier scattering at the interface between pores and matrix while maintaining high-strength phonon scattering,thereby optimizing carrier/phonon transport behaviors,and effectively increasing the ZT by 23.2%(from 0.99 to 1.22 at 350 K).Besides,our strategy has excellent universality confirmed by its effectiveness in improving the ZT of Bi_(2)Te_(2.7)Se_(0.3),therefore demonstrating great potential for developing low-cost and high-performance thermoelectric materials.展开更多
This study explores the impact of bismuth oxide(Bi_(2)O_(3))on the optical and radiation shielding properties of transparent,lead-free thulium-doped bismuth borotellurite radiation shielding glass.The investigated gla...This study explores the impact of bismuth oxide(Bi_(2)O_(3))on the optical and radiation shielding properties of transparent,lead-free thulium-doped bismuth borotellurite radiation shielding glass.The investigated glass composition follows the formula[(TeO_(2))_(75)(B_(2)O_(3))_(25)]_(98-x)(Bi_(2)O_(3))_x[Tm_(2)O_(3)]_(2),where x=0 mol%,5 mol%,10 mol%,15 mol%,20 mol%,25 mol%,and 30 mol%.All glass samples remain transparent,with an optical bandgap(E_(opt))exceeding 3.1 e V,ensuring visible light transmission.Radiation shielding data from Phy-X and XCom reveal interactions of the photoelectric effect,Compton scattering,and pair production,with minimal relative difference in mass attenuation coefficient(MAC)which is between0.05 and 0.56.At 0.662 Me V photon energy,the 20 mol%and 25 mol%Bi_(2)O_(3)glasses exhibit significantly higher Phy-X MAC values than other samples,except RS 520 glass,which contains 71%Pb O.Despite incorporating only up to 25 mol%Bi_(2)O_(3),these glasses outperform others in density,half-value layer(HVL),and mean free path(MFP).Correlating E_(opt)and MAC,the 20 mol%Bi_(2)O_(3)glass is the best candidate for transparent radiation shielding glass due to its wide optical bandgap which prevents ionization of trapped holes.Significantly,the linkage between MFP and molar refraction was also discovered based on the particle size influence on both parameters.展开更多
Efficient removal of antibiotics is of great significance for the sustainability of aquatic ecosystems.In this work,a new polyoxometalate-based metal-organic hybrid material[Ag_(3)L_(0.5)(HSiW_(12)O_(4)0)]·2C_(2)...Efficient removal of antibiotics is of great significance for the sustainability of aquatic ecosystems.In this work,a new polyoxometalate-based metal-organic hybrid material[Ag_(3)L_(0.5)(HSiW_(12)O_(4)0)]·2C_(2)H_(5)OH·2CH_(3)CN(Ag-L-SiW_(12))was prepared by using Keggin-type polyoxometalate anion and thiacalix[4]arene-based ligand(L)via solvothermal method.Subsequently,a composite heterojunction Ag-L-SiW_(12)@BiVO_(4)photoanode was fabricated by loading Ag-L-SiW_(12)on the surface of BiVO_(4).The photoelectrocatalytic degradation performance of ciprofloxacin(CIP)was explored under the simulated solar radiation.Remarkably,the CIP degradation efficiency reached 93%within 240 min using the optimal Ag-LSiW_(12)@BiVO_(4)photoanode,which is approximately 2 and 23 times those of pristine BiVO_(4)and Ag-L-SiW_(12),respectively.Furthermore,density functional theory(DFT)calculations were conducted to elucidate the role of Ag-L-SiW_(12)during the photoelectrocatalytic process.This work offers an example of the efficient composite photoelectrocatalysts for the treatment of antibiotic wastewater.展开更多
The efficient utilization of photogenerated electrons and the effective activation of reactive molecules are among the major challenges in photocatalytic nitrogen reduction.Defect engineering can enhance the catalyst&...The efficient utilization of photogenerated electrons and the effective activation of reactive molecules are among the major challenges in photocatalytic nitrogen reduction.Defect engineering can enhance the catalyst's ability to adsorb and activate N_(2)and H_(2)O,while the ultrathin structure with maximized active crystal facets can maximize the enrichment of effective photogenerated electrons.This work employs a two-step synergistic method to fabricate ultrathin BiVO_(4)with oxygen vacancies and bismuth vacancies(2D-V_(Bi+O)-BVO,thickness<20 nm)for photocatalytic nitrogen reduction.Scanning electron microscopy,transmission electron microscopy(TEM),and atomic force microscopy characterization confirm the transformation of BiVO_(4)from bulk material(bulk-BVO,~1300 nm)to an ultrathin structure(~15 nm).TEM,X-ray photoelectron spectroscopy,electron paramagnetic resonance characterizations,and density functional theory(DFT)calculations verify the construction of oxygen and bismuth vacancies in the ultrathin BiVO_(4).Compared to bulk-BVO,the photocatalytic nitrogen fixation efficiency of 2D-V_(Bi+O)-BVO is increased by 4.7 times,with the highest activity reaching 158.73μmol·g^(-1)·h^(-1).N_(2)-temperature programmed desorption and DFT calculations demonstrate that the oxygen and bismuth vacancies in BiVO_(4),respectively,promote the adsorption/activation of N_(2)and H_(2)O,which is crucial for the overall nitrogen reduction reaction.Photo-deposition experiments prove that the(040)plane is the active surface for electrons.And the ultrathin structure maximizes the(040)facet of BiVO_(4),which is conducive to the high enrichment of electrons.Meanwhile,more active sites can be exposed for the activation of N_(2)and H_(2)O.In situ infrared spectroscopy confirms that N_(2)can be effectively adsorbed onto 2D-V_(Bi+O)-BVO,and the presence of NH_(2)-NH_(2)active species is consistent with the alternating reaction pathway.This study provides new insights into the development of green and efficient photocatalysts with dual vacancies and ultrathin structures.展开更多
As one of the alloy-type lithium-ion electrodes,Bi has outstanding application prospects for large volume capacity(3800 mAh·cm^(-3))and high electronic conductivity(1.4×10^(7)S·m^(-1)).However,the fast-...As one of the alloy-type lithium-ion electrodes,Bi has outstanding application prospects for large volume capacity(3800 mAh·cm^(-3))and high electronic conductivity(1.4×10^(7)S·m^(-1)).However,the fast-charging performance is hindered by significant volume expansion(>218%)and a low rate of phase diffusion.To overcome these two problems,an N-doped carbon nanoflower coating layer was elaborately in-situ reconstructed on a multiple-wall Bi microsphere by hydrothermal methods and subsequent calcination in this study.The carbon nanoflowers greatly increase specific surface area(40.0 m^(2)·g^(-1))and alleviate the volume expansion(130%).In addition,the incorporation of N-doped carbon nanoflowers leads to a gradual enhancement in the Li adsorption energy of Bi during the process of lithium insertion and improves the electrical conductivity.Therefore,the contribution rate of pseudo-capacitance reached 87.5%at the scan rate of 0.8 mV·s^(-1),and the Li-ion diffusion coefficient(D_(Li^(+)))was calculated in the range of 10^(-10)to 10^(-12)cm^(2)·s^(-1).The Bi@CNFs anode provided a high specific volumetric capacity of 2117.0 mAh·cm^(-3)at 5C and a high capacity retention ratio of 93.2%after 800 cycles.The Bi@CNFs//LiFePO_(4)full cell also displayed a stable capacity of 113.9 mAh·g^(-1)and energy density of 296.1 Wh·kg^(-1)after 100 cycles with a Coulombic efficiency of 97.6%.The mechanism of fast-charging lithium storage was verified by distribution of relaxation time analysis and density functional theory calculation.This paper provides a new strategy to increase the pseudo-capacitance and reduce the volume expansion for the preparation of alloy-type fast-charging electrodes.展开更多
The advancement in catalysis techniques for sustainable environmental applications,particularly an alternative to the current Haber-Bosch process for NH_(3),has recently gained widespread attention.Although photocatal...The advancement in catalysis techniques for sustainable environmental applications,particularly an alternative to the current Haber-Bosch process for NH_(3),has recently gained widespread attention.Although photocatalytic conversion of N_(2) to NH_(3) using solar energy is an eco-friendly method,it has the limitation of low quantum yield.Recently,2D Bi-based photocatalysts which exhibit higher visible light absorption than TiO_(2) and higher stability than MXene have been an active research topic,and their performance can be enhanced through improved visible light absorption properties by incorporating plasmonic gold nanoparticles while nitrogen adsorption could be enhanced through oxygen vacancy(OV)processes.In the present study,we explore the application of 2D nanosized Bi_(2)O_(3–x) and gold nanoparticles for visible light photo generation of NH_(3).HRTEM and XPS reveal that the formation of AuNP and nano-sized Bi_(2)O_(3–x) in AuNP/Bi_(2)O_(3–x) heterozygote structure promotes the charge carrier mobility and charge transport at the interface,resulting in a 2.6-fold increase in the photocatalytic activity compared to micro-sized Bi_(2)O_(3–x) with AuNP.The improved photocatalytic performance can be ascribed to significant enhancement of visible light absorption by plasmonic nanoparticles,fast charge transport and mobility(due to sheet morphology)and the N_(2) activation by OV in AuNP/Bi_(2)O_(3–x) heterozygote.Through a systematic experimental investigation involving catalysts,concentration,pH,and scavengers,the highest photocatalytic performance was achieved with the heterozygote structures of AuNP/n-Bi_(2)O_(3–x) under optimized conditions,yielding 432.5μmol gcat^(-1) h^(-1) of NH_(3).展开更多
In situ growth of co-catalysts on BiVO_(4)(BVO)to enhance photoelectrochemical(PEC)water splitting performance has been extensively reported.However,the understanding of the synergistic effects among various elements,...In situ growth of co-catalysts on BiVO_(4)(BVO)to enhance photoelectrochemical(PEC)water splitting performance has been extensively reported.However,the understanding of the synergistic effects among various elements,especially at the interface between the semiconductor and cocatalyst,has received insufficient attention.In this study,we report a Co,Ni and Mn trimetallic fluoride-modified BVO photoanode featuring a unique interfacial chemical bond(V-F).Under AM 1.5 G illumination,an exciting photocurrent density of 6.05 mA cm^(-2)was achieved at 1.23 V vs.RHE by the integrated BVO/CoNi_(0.18)Mn_(0.12)(OH)_(x)F photoanode and over 98%of the initial photocurrent was maintained after 10 h of photoelectrolysis.Control experiments and theoretical calculations demonstrate that the V-F interfacial bond stabilizes the Co^(2+)active sites.It serves as a transmission gear,interlinking the migration of interfacial charge and the regeneration of cocatalyst,endowing the photoanode with significant activity and stability.Furthermore,we have systematically elucidated the role of the individual Co,Ni,and Mn components in the synergistic cocatalyst layer.The interfacial modification provides novel insights into developing advanced photoanodes towards PEC water splitting.展开更多
Bismuth telluride-based alloys are the most widely used thermoelectric(TE)materials.Despite this,zonemelted Bi_(2)Te_(3)-based alloys suffer from poor mechanical properties,and polycrystalline materials prepared by po...Bismuth telluride-based alloys are the most widely used thermoelectric(TE)materials.Despite this,zonemelted Bi_(2)Te_(3)-based alloys suffer from poor mechanical properties,and polycrystalline materials prepared by powder metallurgy often disrupt the desired texture due to their inherent anisotropic crystal structure.In this study,we achieved a synergistic integration of nanoscale structures,highly oriented texture,and intrinsic BiTe’antisite defects in P-type Bi_(0.5)Sb_(1.5)Te_(3) bulk materials by employing layered directional sintering(LDS)on melt-spinning ribbons produced in a Bi-rich environment.The transmission electron microscopy analysis revealed regions of high-density distortions within the well-aligned nanograins,which play a crucial role in reducing lattice thermal conductivity.Ab initio simulations and Boltzmann transport equation analyses reveal that the BiTe’antisite defects generate both resonance states and additional phonon scattering channels.This full-spectrum phonon scattering coupled with high carrier mobility leads to a maximum figure of merit(ZT)of 1.54 at 375 K.Additionally,the compressive strength of the material reaches 140 MPa,which is 3.5 times higher than that of zone-melted counterparts.This work offers an efficient pathway for the facile preparation of high-performance Bi_(2)Te_(3)-based thermoelectric materials.展开更多
文摘Novel Er3+-doped bismuth lead strontiam glass was fabricated and characterized, and the absorption spectrum and upconversion spectrum of the glass were studied. The Judd-Ofelt intensity parameters Ωt (t=2, 4, 6) were found to be Ω2=3.27×10-20 cm2, Ω4=1.15×10-20 cm2, and Ω6=0.38×10-20 cm2. The oscillator strength, the spontaneous transition probabilities, the fluorescence branching ratios, and excited state lifetimes were also measured and calculated. The upconversion emission intensity varies with the power of infrared excitation intensity. A plot of log Iup vs log IIR yields a straight line with slope 1.86, 1.88 and 1.85, corresponding to 525, 546, and 657 nm emission bands, respectively, which indicates that a two-photon process for the red and green emission.
基金supported by the Guangdong Major Project of Basic and Applied Basic Research(2023B0303000002)the National Natural Science Foundation of China(No.52206089)+3 种基金the Guangdong Basic and Applied Basic Research Foundation(2024A1515010288,2023B1515120005)the Natural Science Foundation of Shenzhen(JCYJ20230807093315033)the Shenzhen Engineering Research Center,Southern University of Science and Technology(No.XMHT20230208003)high level of special funds(G03034K001)。
文摘All-vanadium flow batteries(VFBs)are one of the most promising large-scale energy storage technologies.Conducting an operando quantitative analysis of the polarizations in VFBs under different conditions is essential for developing high power density batteries.Here,we employ an operando decoupling method to quantitatively analyze the polarizations in each electrochemical and chemical reaction of VFBs under different catalytic conditions.Results show that the reduction reaction of V^(3+)presents the largest activation polarization,while the reduction reaction of VO_(2)^(+)primarily contributes to concentration polarizations due to the formation of the intermediate product V_(2)O_(3)^(3+).Additionally,it is found that the widely used electrode catalytic methods,incorporating oxygen functional groups and electrodepositing Bi,not only enhance the reaction kinetics but also exacerbate concentration polarizations simultaneously,especially during the discharge process.Specifically,in the battery with the high oxygen-containing electrodes,the negative side still accounts for the majority of activation loss(75.3%)at 200 mA cm^(-2),but it comes down to 36,9% after catalyzing the negative reactions with bismuth.This work provides an effective way to probe the limiting steps in flow batteries under various working conditions and offers insights for effectively enhancing battery performance for future developments.
基金financially supported by the Natural Science Foundation of Zhejiang Province, China (Grant No. LQ22F040001)China Postdoctoral Science Foundation (Grant No. 2022M723281)Science and Technology Planning Project of Shaoxing City (Grant No. 2023B41006)。
文摘Owing to their low toxicity and remarkable stability, perovskites based on antimony and bismuth have garnered significant interest in recent years. However, A_(3)B_(2)X_(9) perovskite materials derived from antimony and bismuth face several challenges, including excessively wide band gaps, elevated defect densities, and suboptimal film quality, all of which hinder advancements in device efficiency. While extensive studies have been undertaken to investigate the effects of modulating the A-site and X-site elements in lead-free A_(3)B_(2)X_(9) perovskites, there remains a notable scarcity of reports addressing the impact of modifications to the B-site element. In this study, we investigated the alloying of antimony and bismuth within the 2D Cs_(3)B_(2)I_(6)Br_(3) perovskite. By systematically varying the ratios of two elements, we found that the incorporation of both antimony and bismuth at the B-site significantly enhances the quality of the perovskite films. Our findings indicate that a 1 : 1 ratio of antimony to bismuth produces the densest films, the highest photoluminescence intensity, and superior photovoltaic performance. Ultimately,the devices fabricated using this optimal ratio achieved an open-circuit voltage(VOC) of 1.01 V and a power conversion efficiency(PCE) of 0.645%.
基金Project supported by the Key R&D Projects in Hunan Province(2021SK2047,2022NK2044)Science and Technology Innovation Program of Hunan Province(2022WZ1022)Superior Youth Project of the Science Research Project of Hunan Provincial Department of Education(22B0211)。
文摘The technology of solid-state lighting has developed for decades in various industries.Phosphor,as an element part,determines the application domain of lighting products.For instance,blue and redemitting phosphors are required in the process of plant supplementing light,arrow-band emitting phosphors are applied to backlight displays,etc.In this work,a Bi^(3+)-activated blue phosphor was obtained in a symmetrical and co mpact crystal structure of Gd3Sb07(GSO).Then,the co-doping strategy of alkali metal ions(Li^(+),Na^(+),and K^(+))was used to optimize the performance.The result shows that the photoluminescence intensity is increased by 2.1 times and 1.3 times respectively by introducing Li~+and K^(+)ions.Not only that,it also achieves narrow-band emitting with the full width of half-maximum(FWHM)reaching 42 nm through Na^(+)doping,and its excitation peak position also shifts from 322 to 375 nm,which can be well excited by near-ultraviolet(NUV)light emitting diode(LED)chips(365 nm).Meanwhile,the electroluminescence spectrum of GSO:0.6 mol%Bi^(3+),3 wt%Na^(+)matches up to 93.39%of the blue part of the absorption spectrum of chlorophyll a.In summary,the Bi^(3+)-activated blue phosphor reported in this work can synchronously meet the requirements of plant light replenishment and field emission displays.
文摘Solving the problems of carbon dioxide(CO_(2))emissions and energy scarcity by the development of highly selective,cost-effective,and reliable catalysts for the electrochemical reduction of CO_(2)to useful carbon-based products would be very helpful.We report the synthesis of an efficient graphene-supported bismuth single-atom catalyst(BiSA-G)featuring a BiN_(4)coordination structure for this purpose.The synthesis used tannic acid as a multifunctional ligand and ammonia as a nitrogen dopant.Using a scalable coordination chemistry approach,BiN_(4)sites were uniformly dispersed on the graphene substrate and were found to have an outstanding ability for the conversion of CO_(2)to CO,with a high Faradaic efficiency of 97.4%at−0.55 V(vs.RHE)and a high turnover frequency of 5230 h^(−1)along with outstanding stability.Density functional theory calculations confirmed that the BiN_(4)site serves as the dominant active center,simultaneously facilitating CO_(2)activation and the efficient formation of the crucial intermediate*COOH with a reduced free energy barrier.This discovery offers a new way for the atomic-scale design of high-efficiency catalysts for the electrochemical CO_(2)reduction reaction,potentially helping sustainable carbon use.
文摘Iron(Fe)nanoparticles and graphite(Gr)with different masses of bismuth trisulfide(Bi_(2)S_(3))were mixed by high-energy ball milling treatment to fabricate the corresponding composite iron anodes Bi_(2)S_(3)@Fe-Gr.The hydrogen evolution reaction and iron passivation process on these iron electrodes were investigated in alkaline and neutral solutions.The iron electrode Bi_(2)S_(3)-3@Fe-Gr(The additional amount of Bi_(2)S_(3)was 3 mg)revealed the strongest ability to inhibit hydrogen evolution among the iron electrodes of the present investigation,while the Bi_(2)S_(3)-6@Fe-Gr electrode(The additional amount of Bi_(2)S_(3)was 6 mg)delivered significant performance in inhibiting anodic passivation.This is because the high-energy ball milling process leads to the well-dispersion of Bi_(2)S_(3)and the changes in the surface of Fe nanoparticles,thereby slowing down the passivation of the iron electrode surface.
基金国家自然科学基金(12104188,12474095 and 52402323)开放基金(2023KF03,KYCX24-4102)。
文摘Introduction Pure NBT exhibits the frequency-dependent Curie temperature,indicating that its dielectric properties are affected by temperature,measurement frequency,and material processing condition.To enhance the dielectric and relaxor properties of NBT,various dopants such as Sr,K,Li and Bi are incorporated into the NBT structure.These modifications significantly alter the dielectric constant and relaxation behavior,demonstrating a dominant influence of dopant on the material properties.Among these,the solid solution of BaTiO_(3)(BT)with NBT is widely investigated due to its ability to stabilize the perovskite structure and improve dielectric performance.However,the temperature-dependent stability of dielectric properties remains a critical challenge for high-temperature applications.In this study,(1-x)(0.75Na_(0.5)Bi_(0.5)TiO_(3)-0.25BaTiO_(3))-xBaZrO_(3)(NBT-BT-xBZ,x=0,0.08,0.14,and 0.20)ceramics were prepared by a solid-state reaction method.The effect of BaZrO_(3)(BZ)addition on the structural,dielectric,and energy storage properties was systematically investigated.In addition,the phase transition and relaxation behaviors were also analyzed based on the modified Curie-Weiss law,Vogel-Fulcher relation,and Lorentz-type empirical law.Methods The starting materials were powders of high purity Na_(2)CO_(3),Bi_(2)O_(3),TiO_(2),BaCO_(3),and ZrO_(2).The powders were weighed according to a stoichiometric ratio(with 1%excess of Na and Bi)and ground with ethanol in a ball mill at 300 r/min for more than 12 h,and the weight ratio of raw material to ethanol and zirconium balls was 1:1:2.The dried material was heat-treated at 850℃ for 2 h to promote the formation of NBT-BT-BZ.After further grinding for 12 h,the samples were mixed with a small amount of polyvinyl alcohol(PVA).The samples were sintered in air at 1150℃for 2 h and cooled to room temperature.The phase composition of the ceramic samples was determined by an model D8 ADVANDCE X-ray diffractometer(D8 ADVANDCEXRD,Bruker AXS Ltd.,Germany)with Cu target Kαrays,at X-ray wavelengthλof 1.5406Å,2θin the range of 10°to 80°,applied voltage of 40 kV,and a current of 500 mA.A silver paste was coated on the two surfaces as electrodes and heat-treated at 700℃ for 10 min.The dielectric properties of the ceramic samples were determined at different frequencies by a model DMS-1000 high-temperature dielectric temperature spectroscope(BALAB Tech.Co.,China)with at a ramp rate of 3(°)/min in a temperature range from room temperature to 450℃.The overdamped(200Ω)discharge tests for bulk ceramic samples were performed by a model CFD-005 discharge tester(Gogo(GG)Instruments Technology,China)).Results and discussion The XRD patterns indicate that all the ceramic samples have a perovskite structure without any detectable secondary phase,proving that zirconium ions can completely enter the lattice and form a solid solution.Based on the locally magnified XRD peaks,the XRD peak shape shifts towards lower angles as a whole as the BZ content increases.This indicates that the overall volume of the crystal cell shows an expansion as the Zr ions replace Ti ions due to different ionic radii of Zr and Ti ions.The SEM images show that the grain size gradually increases with increasing the BZ content.The addition of BZ promotes the grain growth.However,this gradually slows down with the increase of content up to x of 0.20.The limited grain size variation appears in the latter two samples.All the samples show a relatively dense morphology.The Curie temperature of the NBT-0.25BT ceramic samples is 256℃,which is similar to the reported results.The Curie temperature decreases gradually with the increase of BZ additive,and the dielectric temperature spectrum flattens out,indicating that the enhanced structural and temperature stability of the NBT-BT-BZ ceramics.The maximum values of all dielectric constants correspond to temperatures that increase with frequency,indicating a dielectric relaxor behavior.A frequency dispersion is accompanied at near the Curie temperature,which can be ascribed to the thermal evolution of the tetragonal polar nanoregions(PNRs)and the mixing effect of the transition from tripartite to tetragonal PNRs.Theγvalues obtained from the experimental data at 100 kHz are 1.79,1.83,1.89,and 1.92 for NBT-BT,NBT-BT-0.08BZ,NBT-BT-0.14BZ,and NBT-BT-0.20BZ,respectively.Theγvalue increases gradually with the addition of the BZ content,showing an enhanced relaxation of the NBT-BT-BZ ceramics.The comparison of discharge current curves and energy density of all the ceramics indicate that the addition of BZ significantly improves the discharge current and energy storage performance.A high discharging energy density(Wd)of 1.6 J·cm^(-3) with a fast discharging speed(τ0.9)of 75 ns is obtained for the ceramic samples with x of 0.14.This can be attributed to an increased relaxation as the BZ content increases.Conclusions NBT-BT-BZ ceramics were prepared by a solid-state reaction method.The XRD patterns revealed a phase transition from a tetragonal phase to a pseudocubic phase as the BZ content increased.The dielectric relaxation behavior of the ceramics could be described by three empirical laws(i.e.,modified Curie-Weiss law,Vogel-Fulcher relation and Lorentz-type empirical law).The dielectric relaxation followed the modified Curie-Weiss law and the Vogel-Fulcher relationship.The parametersγand Ea,which were obtained to evaluate the relaxation behavior,increased at a higher BZ content.The Lorentz-type relationship effectively described the temperature dependence of the dielectric constant on both the low-and high-temperature sides within a specific temperature range for all the ceramics.
基金National Natural Science Foundation of China (51932010)。
文摘High-temperature piezoelectric vibration sensors are the preferred choice for structural health monitoring in harsh environments such as high temperatures and complex vibrations.Bismuth layer-structured CaBi_(4)Ti_(4)O_(15)(CBT)high-temperature piezoelectric ceramics,with high Curie temperature(TC),are the key components for piezoelectric vibration sensors operating at temperatures exceeding 500℃.However,their low piezoelectric coefficient(d_(33))greatly limits their high-temperature applications.In this work,a novel Bi^(3+)self-doping strategy was employed to enhance the piezoelectric performance of CBT ceramics.The enhancement is attributed to an increase in the number of grain boundaries,providing more sites for space charge accumulation and promoting formation of space charge polarization.Furthermore,given that space charge polarization predominantly occurs at low frequencies,dielectric temperature spectra at different frequencies were used to elucidate the mechanism by which space charge polarization enhances piezoelectric properties of CBT ceramics.Excellent overall performance was achieved for the CBT-based high-temperature piezoelectric ceramics.Among them,TC reached 778℃,d_(33) increased by more than 30%,reaching 20.1 pC/N,and the electrical resistivity improved by one order of magnitude(reaching 6.33×10^(6)Ω·cm at 500℃).These advancements provide a key functional material with excellent performance for practical applications of piezoelectric vibration sensors at 500℃and above.
基金supported by the National Natural Science Foundation of China(Grants 22472075 and 22272075).
文摘A recent paper published in Journal of the American Chemical Society by W.Zhang and co-workers reported a ground-breaking advance by establishing 209 Bi and 127 I ultra-wideline solid-state NMR(UW SSNMR)as powerful tools for probing bismuth and iodine ions in metal-organic frameworks(MOFs),despite the severe challenges associated with their exceptionally large quadrupolar interactions,and enabled the elucidation of key structural features that are otherwise difficult to access[1].
基金supported by the National Natural Science Foundation of China (Grant No. 12174382)the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant Nos. XDB0460000 and XDB28000000)the Innovation Program for Quantum Science and Technology (Grant Nos. 2024ZD0300104 and 2021ZD0302600)。
文摘The competition between dimensionality and ordering in multiferroic materials is of great interest for both fundamental physics and potential applications. Combining first-principles calculations with micromagnetic simulations, we investigate recently synthesized ultrathin perovskite bismuth ferrite(BFO) films. Our numerical results reveal that, at the monolayer limit, the ferroelectricity of BFO is missing because the octahedral distortions are constrained. However, the monolayer bismuth ferrite is a topological antiferromagnetic metal with tunable bimeron magnetic structure. The dual topologically non-trivial characteristics make monolayer bismuth ferrite a multifunctional building block in future spintronic devices.
基金Projects(52104355,52074363,52374364)supported by the National Natural Science Foundation of ChinaProject(2023YFC2907904)supported by the National Key R&D Program of China。
文摘Traditional pyrometallurgical and hydrometallurgical methods to extract bismuth from sulfide ores face problems such as high cost,low-concentration SO_(2)generation,and long process time.In this study,the cyclone technology and slurry electrolysis method were combined.The bismuth sulfide ore was dissolved directly at the anode,while the high purity bismuth was deposited efficiently at the cathode under the advantages of the two methods.The short process and high-efficiency extraction of bismuth sulfide ore were realized,and the pollution of low-concentration SO_(2)was avoided.Then,the effects of several crucial experimental conditions(current density,reaction time,temperature,pH,liquid-solid ratio,and circulation flow rate)on the leaching efficiency and recovery efficiency of bismuth were investigated.The leaching and electrowinning mechanisms during the recovery process were also analyzed according to the research results of this paper to better understand the cyclone slurry electrolysis process.The experimental results showed that 95.19%bismuth was leached into the acid solution in the anode area under optimal conditions,and the recovery efficiency and purity of bismuth on the cathode reached 91.13%and 99.26%,respectively,which were better than those by the traditional hydrometallurgy recovery process.
基金financially supported by the Natural Science Foundation of Shandong Province(No.ZR2023MB151)the Natural Science Foundation of Shandong Province for Excellent Young Scholars(No.ZR2022YQ13)+1 种基金the Science and Technology Special Project of Qingdao(No.24-1-8-xdny-18nsh)the Taishan Scholar Project of Shandong Province(No.tsqn202211159)
文摘The piezocatalytic characteristic of bismuth oxyhalides(BiOX,X=Cl,Br,and I) has been increasingly capturing interest for its potential in hydrogen evolution reaction(HER) through water splitting process.The performance regarding these piezocatalysts is closely related to the halogen element present in BiOX;yet,the specific influence mechanisms remain unclear.In this study,we prepared BiOX catalysts via a hydrothermal process and explored their piezocatalytic HER activities.Owing to the layered bismuth s tructure,the resulting sheet-like piezocatalysts can efficiently capture the mechanic stimulus and allow the robust piezoelectric field,contributing to the piezocatalytic operation.It demonstrates that the BiOBr achieves a remarkable piezocatalytic HER efficiency of 813 μmol g^(-1)h^(-1),outperforming BiOCl and BiOI.The density functional theory(DFT)calculation results reveal that the BiOBr with moderate halogen atom size and lattice layer spacing possesses the strongest piezoelectricity,which enhances the separation and transfer of electron-hole pairs.Meanwhile,the exposed Br atom layer facilitates a large Bader charge and a low surface Gibbs free energy(ΔG_(H)),enhancing charge transfer for hydrogen reduction at the solid-liquid surface,thereby increasing the HER efficiency.This research sheds light on the halogen-dependent piezocatalytic activity of BiOX catalysts,offering valuable insights for the development of high-performance piezocatalysts.
基金supported by the National Natural Science Foundation of China(Nos.U21A2054,21905007)the Key Discipline of Materials Science and Engineering,Bureau of Education of Guangzhou(Grant No.202255464).
文摘The bismuth-telluride-based alloy is the only thermoelectric material commercialized for the applications of refrigeration and energy harvesting,but its low cost-effectiveness severely restricts its large-scale ap-plication.The introduction of a porous structure in bulk thermoelectric materials has been theoretically proven to effectively reduce thermal conductivity and cost.However,the electrical properties of highly porous materials are considerably suppressed due to the strong carrier scattering at the interface be-tween the matrix and pores,ultimately leading to decreased figure of merit,ZT.Here,we use an atomic layer deposition strategy to introduce some hollow glass bubbles with nano-oxide layers into commercial Bi_(0.5)Sb_(1.5)Te_(3)for preparing high-performance porous thermoelectric materials.Experimental results indi-cate that the nano-oxide layers weaken carrier scattering at the interface between pores and matrix while maintaining high-strength phonon scattering,thereby optimizing carrier/phonon transport behaviors,and effectively increasing the ZT by 23.2%(from 0.99 to 1.22 at 350 K).Besides,our strategy has excellent universality confirmed by its effectiveness in improving the ZT of Bi_(2)Te_(2.7)Se_(0.3),therefore demonstrating great potential for developing low-cost and high-performance thermoelectric materials.
基金funded by the National Defence University of Malaysia(Grant No.UPNM/2022/GPJP/SG/3)My Brain Sc Scholarship 2023。
文摘This study explores the impact of bismuth oxide(Bi_(2)O_(3))on the optical and radiation shielding properties of transparent,lead-free thulium-doped bismuth borotellurite radiation shielding glass.The investigated glass composition follows the formula[(TeO_(2))_(75)(B_(2)O_(3))_(25)]_(98-x)(Bi_(2)O_(3))_x[Tm_(2)O_(3)]_(2),where x=0 mol%,5 mol%,10 mol%,15 mol%,20 mol%,25 mol%,and 30 mol%.All glass samples remain transparent,with an optical bandgap(E_(opt))exceeding 3.1 e V,ensuring visible light transmission.Radiation shielding data from Phy-X and XCom reveal interactions of the photoelectric effect,Compton scattering,and pair production,with minimal relative difference in mass attenuation coefficient(MAC)which is between0.05 and 0.56.At 0.662 Me V photon energy,the 20 mol%and 25 mol%Bi_(2)O_(3)glasses exhibit significantly higher Phy-X MAC values than other samples,except RS 520 glass,which contains 71%Pb O.Despite incorporating only up to 25 mol%Bi_(2)O_(3),these glasses outperform others in density,half-value layer(HVL),and mean free path(MFP).Correlating E_(opt)and MAC,the 20 mol%Bi_(2)O_(3)glass is the best candidate for transparent radiation shielding glass due to its wide optical bandgap which prevents ionization of trapped holes.Significantly,the linkage between MFP and molar refraction was also discovered based on the particle size influence on both parameters.
基金supported by the National Natural Science Foundation of China(Grant No.21471029).
文摘Efficient removal of antibiotics is of great significance for the sustainability of aquatic ecosystems.In this work,a new polyoxometalate-based metal-organic hybrid material[Ag_(3)L_(0.5)(HSiW_(12)O_(4)0)]·2C_(2)H_(5)OH·2CH_(3)CN(Ag-L-SiW_(12))was prepared by using Keggin-type polyoxometalate anion and thiacalix[4]arene-based ligand(L)via solvothermal method.Subsequently,a composite heterojunction Ag-L-SiW_(12)@BiVO_(4)photoanode was fabricated by loading Ag-L-SiW_(12)on the surface of BiVO_(4).The photoelectrocatalytic degradation performance of ciprofloxacin(CIP)was explored under the simulated solar radiation.Remarkably,the CIP degradation efficiency reached 93%within 240 min using the optimal Ag-LSiW_(12)@BiVO_(4)photoanode,which is approximately 2 and 23 times those of pristine BiVO_(4)and Ag-L-SiW_(12),respectively.Furthermore,density functional theory(DFT)calculations were conducted to elucidate the role of Ag-L-SiW_(12)during the photoelectrocatalytic process.This work offers an example of the efficient composite photoelectrocatalysts for the treatment of antibiotic wastewater.
文摘The efficient utilization of photogenerated electrons and the effective activation of reactive molecules are among the major challenges in photocatalytic nitrogen reduction.Defect engineering can enhance the catalyst's ability to adsorb and activate N_(2)and H_(2)O,while the ultrathin structure with maximized active crystal facets can maximize the enrichment of effective photogenerated electrons.This work employs a two-step synergistic method to fabricate ultrathin BiVO_(4)with oxygen vacancies and bismuth vacancies(2D-V_(Bi+O)-BVO,thickness<20 nm)for photocatalytic nitrogen reduction.Scanning electron microscopy,transmission electron microscopy(TEM),and atomic force microscopy characterization confirm the transformation of BiVO_(4)from bulk material(bulk-BVO,~1300 nm)to an ultrathin structure(~15 nm).TEM,X-ray photoelectron spectroscopy,electron paramagnetic resonance characterizations,and density functional theory(DFT)calculations verify the construction of oxygen and bismuth vacancies in the ultrathin BiVO_(4).Compared to bulk-BVO,the photocatalytic nitrogen fixation efficiency of 2D-V_(Bi+O)-BVO is increased by 4.7 times,with the highest activity reaching 158.73μmol·g^(-1)·h^(-1).N_(2)-temperature programmed desorption and DFT calculations demonstrate that the oxygen and bismuth vacancies in BiVO_(4),respectively,promote the adsorption/activation of N_(2)and H_(2)O,which is crucial for the overall nitrogen reduction reaction.Photo-deposition experiments prove that the(040)plane is the active surface for electrons.And the ultrathin structure maximizes the(040)facet of BiVO_(4),which is conducive to the high enrichment of electrons.Meanwhile,more active sites can be exposed for the activation of N_(2)and H_(2)O.In situ infrared spectroscopy confirms that N_(2)can be effectively adsorbed onto 2D-V_(Bi+O)-BVO,and the presence of NH_(2)-NH_(2)active species is consistent with the alternating reaction pathway.This study provides new insights into the development of green and efficient photocatalysts with dual vacancies and ultrathin structures.
基金supported by the project of the National Natural Science Foundation of China(NSFC,Nos.5216040127,52164048 and U1802256)Central Guidance for Local Science and Technology Development Funds(No.202107AB110011)the Analysis and Test Funds of Kunming University of Science and Technology(No.2021M0202230188).
文摘As one of the alloy-type lithium-ion electrodes,Bi has outstanding application prospects for large volume capacity(3800 mAh·cm^(-3))and high electronic conductivity(1.4×10^(7)S·m^(-1)).However,the fast-charging performance is hindered by significant volume expansion(>218%)and a low rate of phase diffusion.To overcome these two problems,an N-doped carbon nanoflower coating layer was elaborately in-situ reconstructed on a multiple-wall Bi microsphere by hydrothermal methods and subsequent calcination in this study.The carbon nanoflowers greatly increase specific surface area(40.0 m^(2)·g^(-1))and alleviate the volume expansion(130%).In addition,the incorporation of N-doped carbon nanoflowers leads to a gradual enhancement in the Li adsorption energy of Bi during the process of lithium insertion and improves the electrical conductivity.Therefore,the contribution rate of pseudo-capacitance reached 87.5%at the scan rate of 0.8 mV·s^(-1),and the Li-ion diffusion coefficient(D_(Li^(+)))was calculated in the range of 10^(-10)to 10^(-12)cm^(2)·s^(-1).The Bi@CNFs anode provided a high specific volumetric capacity of 2117.0 mAh·cm^(-3)at 5C and a high capacity retention ratio of 93.2%after 800 cycles.The Bi@CNFs//LiFePO_(4)full cell also displayed a stable capacity of 113.9 mAh·g^(-1)and energy density of 296.1 Wh·kg^(-1)after 100 cycles with a Coulombic efficiency of 97.6%.The mechanism of fast-charging lithium storage was verified by distribution of relaxation time analysis and density functional theory calculation.This paper provides a new strategy to increase the pseudo-capacitance and reduce the volume expansion for the preparation of alloy-type fast-charging electrodes.
基金Financial support for this work by the National Research Foundation of Korea(2022R1F1A1074682,2022R1A4A1031687)Korea University,and the KU-KIST Research Fund.
文摘The advancement in catalysis techniques for sustainable environmental applications,particularly an alternative to the current Haber-Bosch process for NH_(3),has recently gained widespread attention.Although photocatalytic conversion of N_(2) to NH_(3) using solar energy is an eco-friendly method,it has the limitation of low quantum yield.Recently,2D Bi-based photocatalysts which exhibit higher visible light absorption than TiO_(2) and higher stability than MXene have been an active research topic,and their performance can be enhanced through improved visible light absorption properties by incorporating plasmonic gold nanoparticles while nitrogen adsorption could be enhanced through oxygen vacancy(OV)processes.In the present study,we explore the application of 2D nanosized Bi_(2)O_(3–x) and gold nanoparticles for visible light photo generation of NH_(3).HRTEM and XPS reveal that the formation of AuNP and nano-sized Bi_(2)O_(3–x) in AuNP/Bi_(2)O_(3–x) heterozygote structure promotes the charge carrier mobility and charge transport at the interface,resulting in a 2.6-fold increase in the photocatalytic activity compared to micro-sized Bi_(2)O_(3–x) with AuNP.The improved photocatalytic performance can be ascribed to significant enhancement of visible light absorption by plasmonic nanoparticles,fast charge transport and mobility(due to sheet morphology)and the N_(2) activation by OV in AuNP/Bi_(2)O_(3–x) heterozygote.Through a systematic experimental investigation involving catalysts,concentration,pH,and scavengers,the highest photocatalytic performance was achieved with the heterozygote structures of AuNP/n-Bi_(2)O_(3–x) under optimized conditions,yielding 432.5μmol gcat^(-1) h^(-1) of NH_(3).
文摘In situ growth of co-catalysts on BiVO_(4)(BVO)to enhance photoelectrochemical(PEC)water splitting performance has been extensively reported.However,the understanding of the synergistic effects among various elements,especially at the interface between the semiconductor and cocatalyst,has received insufficient attention.In this study,we report a Co,Ni and Mn trimetallic fluoride-modified BVO photoanode featuring a unique interfacial chemical bond(V-F).Under AM 1.5 G illumination,an exciting photocurrent density of 6.05 mA cm^(-2)was achieved at 1.23 V vs.RHE by the integrated BVO/CoNi_(0.18)Mn_(0.12)(OH)_(x)F photoanode and over 98%of the initial photocurrent was maintained after 10 h of photoelectrolysis.Control experiments and theoretical calculations demonstrate that the V-F interfacial bond stabilizes the Co^(2+)active sites.It serves as a transmission gear,interlinking the migration of interfacial charge and the regeneration of cocatalyst,endowing the photoanode with significant activity and stability.Furthermore,we have systematically elucidated the role of the individual Co,Ni,and Mn components in the synergistic cocatalyst layer.The interfacial modification provides novel insights into developing advanced photoanodes towards PEC water splitting.
基金financially supported by the National Natural Science Foundation of China(No.51874111).
文摘Bismuth telluride-based alloys are the most widely used thermoelectric(TE)materials.Despite this,zonemelted Bi_(2)Te_(3)-based alloys suffer from poor mechanical properties,and polycrystalline materials prepared by powder metallurgy often disrupt the desired texture due to their inherent anisotropic crystal structure.In this study,we achieved a synergistic integration of nanoscale structures,highly oriented texture,and intrinsic BiTe’antisite defects in P-type Bi_(0.5)Sb_(1.5)Te_(3) bulk materials by employing layered directional sintering(LDS)on melt-spinning ribbons produced in a Bi-rich environment.The transmission electron microscopy analysis revealed regions of high-density distortions within the well-aligned nanograins,which play a crucial role in reducing lattice thermal conductivity.Ab initio simulations and Boltzmann transport equation analyses reveal that the BiTe’antisite defects generate both resonance states and additional phonon scattering channels.This full-spectrum phonon scattering coupled with high carrier mobility leads to a maximum figure of merit(ZT)of 1.54 at 375 K.Additionally,the compressive strength of the material reaches 140 MPa,which is 3.5 times higher than that of zone-melted counterparts.This work offers an efficient pathway for the facile preparation of high-performance Bi_(2)Te_(3)-based thermoelectric materials.
