Intergrowth ferroelectric semiconductors with excellent spontaneous polarization field are highly promising piezo-photocatalytic candidate materials.In addition,developing structural design and revealing polarization ...Intergrowth ferroelectric semiconductors with excellent spontaneous polarization field are highly promising piezo-photocatalytic candidate materials.In addition,developing structural design and revealing polarization enhancement in-depth mechanism are top priorities.Herein,we introduce the intergrowth ferroelectrics Bi_(7)Ti_(4)NbO_(21)thin-layer nanosheets for piezo-photocatalytic CO_(2)reduction.Density functional theory(DFT)calculations indicate that interlayer lattice mismatch leads to increased tilting and rotation angle of Ti/NbO_(6)octahedra on perovskite-like layers,serving as the main reason for increased polarization.Furthermore,the tilting and rotation angle of the interlayer octahedron further increase under stress,suggesting a stronger driving force generated to facilitate charge carrier separation efficiency.Meanwhile,Bi_(7)Ti_(4)NbO_(21)nanosheets provide abundant active sites to effectively adsorb CO_(2)and acquire sensitive stress response,thereby presenting synergistically advanced piezo-photocatalytic CO_(2)reduction activity with a high CO generation rate of 426.97μmol g^(-1)h^(-1).Our work offers new perspectives and directions for initiating and investigating the mechanisms of high-performance intergrowth piezo-photocatalysts.展开更多
Octahedral Fe_(3)O_(4)-modified coke Fenton catalyst(Fe_(3)O_(4)/PCWQ)was prepared via in-situ one-pot oxidation method inspired by grapefruit peel,and characterized by SEM,EDS,XRD,XPS,FTIR,BET,VSM,and Raman,respectiv...Octahedral Fe_(3)O_(4)-modified coke Fenton catalyst(Fe_(3)O_(4)/PCWQ)was prepared via in-situ one-pot oxidation method inspired by grapefruit peel,and characterized by SEM,EDS,XRD,XPS,FTIR,BET,VSM,and Raman,respectively.Fe_(3)O_(4)crystals was predominantly in octahedral morphology with an average particle size of 60 nm.Fe_(3)O_(4)/PCWQ exhibited graphene-like structure.The synergistic effect between oxygen functional group and Fe^(2+)/Fe^(3+)cycle in Fe_(3)O_(4)/PCWQ enhances the degradation performance of p-nitrophenol(P-NP).Under the optimal conditions(1.0 g/L catalyst,30 mmol/L H_(2)O_(2),pH 3.0,25℃),Fe_(3)O_(4)/PCWQ exhibits high degradation efficiency of P-NP(91.25%in 30 min and 98.21%in 180 min)and stability(90.72%after 6 cycles)with low iron leaching(<0.528 mg/L),following the quasi-first-order degradation kinetics.Fe_(3)O_(4)/PCWQ has better catalytic performance than pure Fe_(3)O_(4)under the action of H_(2)O_(2),and is an efficient,stable and repeatable green catalyst.展开更多
Topochemical fluorination introduces significant structural distortions and emerging properties in perovskite oxides via substituting oxygen with fluorine.However,the rapid fluorination process and the similarity betw...Topochemical fluorination introduces significant structural distortions and emerging properties in perovskite oxides via substituting oxygen with fluorine.However,the rapid fluorination process and the similarity between F and O render the O/F site occupation and local lattice evolution during fluorination unclear.Here we investigated the atomic-scale O/F exchange in La2CoO4and quantified the lattice distortion of three ordered structures:La_(2)CoO_(3.5)F,La_(2)CoO_(3)F_(2),and La_(2)CoO_(2.5)F_(3)by utilizing aberration-corrected electron microscopy.Atomic-resolved elemental mapping provides direct evidence for the O/F occupancy in interstitial and apical sites.We revealed that apical F ions induce significant octahedral tilting from 178°to 165°,linearly proportional to the occupancy rate;and cause the obvious change in the fine structure O K edge,meanwhile apical O is exchanged into interstitial sites.The strong octahedral tilt leads to the in-plane elongation of the[CoO_(4)F_(2)]octahedra.These findings elucidate the atomic-scale mechanisms of the entire fluorination process and highlight the significant role of F in tuning the octahedral tilt of functional oxides.展开更多
Advanced processes for peroxymonosulfate(PMS)-based oxidation are efficient in eliminating toxic and refractory organic pol-lutants from sewage.The activation of electron-withdrawing HSO_(5)^(-)releases reactive speci...Advanced processes for peroxymonosulfate(PMS)-based oxidation are efficient in eliminating toxic and refractory organic pol-lutants from sewage.The activation of electron-withdrawing HSO_(5)^(-)releases reactive species,including sulfate radical(·SO_(4)^(-)),hydroxyl radical(·OH),superoxide radical(·O_(2)^(-)),and singlet oxygen(1O_(2)),which can induce the degradation of organic contaminants.In this work,we synthesized a variety of M-OMS-2 nanorods(M=Co,Ni,Cu,Fe)by doping Co^(2+),Ni^(2+),Cu^(2+),or Fe^(3+)into manganese oxide oc-tahedral molecular sieve(OMS-2)to efficiently remove sulfamethoxazole(SMX)via PMS activation.The catalytic performance of M-OMS-2 in SMX elimination via PMS activation was assessed.The nanorods obtained in decreasing order of SMX removal rate were Cu-OMS-2(96.40%),Co-OMS-2(88.00%),Ni-OMS-2(87.20%),Fe-OMS-2(35.00%),and OMS-2(33.50%).Then,the kinetics and struc-ture-activity relationship of the M-OMS-2 nanorods during the elimination of SMX were investigated.The feasible mechanism underly-ing SMX degradation by the Cu-OMS-2/PMS system was further investigated with a quenching experiment,high-resolution mass spec-troscopy,and electron paramagnetic resonance.Results showed that SMX degradation efficiency was enhanced in seawater and tap water,demonstrating the potential application of Cu-OMS-2/PMS system in sewage treatment.展开更多
A photocatalyst composed of TiO 2 nanotube arrays（TNTs） and octahedral Cu2 O nanoparticles was fabricated,and its performance in the photocatalytic reduction of CO2 under visible and simulated solar irradiation was ...A photocatalyst composed of TiO 2 nanotube arrays（TNTs） and octahedral Cu2 O nanoparticles was fabricated,and its performance in the photocatalytic reduction of CO2 under visible and simulated solar irradiation was studied. The average nanotube diameter and length was 100 nm and 5 μm,respectively. The different amount of octahedral Cu2 O modified TNTs were obtained by varying electrochemical deposition time. TNTs modified with an optimized amount of Cu2 O nanoparticles exhibited high efficiency in the photocatalysis,and the predominant hydrocarbon product was methane. The methane yield increased with increasing Cu2 O content of the catalyst up to a certain deposition time,and decreased with further increase in Cu2 O deposition time. Insufficient deposition time（5 min） resulted in a small amount of Cu2 O nanoparticles on the TNTs,leading to the disadvantage of harvesting light. However,excess deposition time（45 min） gave rise to entire TNT surface being most covered with Cu2 O nanoparticles with large sizes,inconvenient for the transport of photo-generated carriers. The highest methane yield under simulated solar and visible light irradiation was observed for the catalysts prepared at a Cu2 O deposition time of 15 and 30 min respectively. The morphology,crystallization,photoresponse and electrochemical properties of the catalyst were characterized to understand the mechanism of its high photocatalytic activity. The TNT structure provided abundant active sites for the adsorption of reactants,and promoted the transport of photogenerated carriers that improved charge separation. Modifying the TNTs with octahedral Cu2 O nanoparticles promoted light absorption,and prevented the hydrocarbon product from oxidation. These factors provided the Cu2O-modified TNT photocatalyst with high efficiency in the reduction of CO2,without requiring co-catalysts or sacrificial agents.展开更多
Several catalysts comprising Pt supported on octahedral Fe3O4（Pt/Fe3O4） were prepared by a facile method involving co-precipitation followed by thermal treatment at different temperatures. A variety of characterizat...Several catalysts comprising Pt supported on octahedral Fe3O4（Pt/Fe3O4） were prepared by a facile method involving co-precipitation followed by thermal treatment at different temperatures. A variety of characterization results revealed that this preparation process afforded highly crystalline octahedral Fe3O4 with a uniform distribution of Pt nanoparticles on its surface. The thermal-treatment temperature significantly influenced the redox properties of the Pt/Fe3O4 catalysts. All the Pt/Fe3O4 catalysts were found to be catalytically active and stable for the oxidation of low-concentration formaldehyde（HCHO） with oxygen. The catalyst prepared by thermal treatment at 80 °C（labelled Pt/Fe3O4-80） exhibited the highest catalytic activity, efficiently converting HCHO to CO2 and H2 O under ambient temperature and moisture conditions. The excellent performance of Pt/Fe3O4-80 was mainly attributed to beneficial interactions between the Pt and Fe species that result in the formation a higher density of active interface sites（e.g., Pt-O-FeO x and Pt-OH-FeO x）. The introduction of water vapor improves the catalytic activity of the Pt/Fe3O4 catalysts as it participates in a water-assisted dissociation process.展开更多
Inhibition of foam cell formation is considered a promising treatment method for atherosclerosis,the leading cause of cardiovascular diseases worldwide.However,currently available therapeutic strategies have shown uns...Inhibition of foam cell formation is considered a promising treatment method for atherosclerosis,the leading cause of cardiovascular diseases worldwide.However,currently available therapeutic strategies have shown unsatisfactory clinical outcomes.Thus,herein,we design aloperine(ALO)-loaded and hyaluronic acid(HA)-modified palladium(Pd)octahedral nanozymes(Pd@HA/ALO)that can synergistically scavenge reactive oxygen species(ROS)and downregulate cyclooxygenase-2(COX-2)expression to induce macrophage polarization,thus inhibiting foam cell formation to attenuate atherosclerosis.Due to the targeted effect of HA on stabilin-2 and CD44,which are overexpressed in atherosclerotic plaques,Pd@HA/ALO can actively accumulate in atherosclerotic plaques.Subsequently,the antioxidative effects of Pd octahedral nanozymes are mediated by their intrinsic superoxide dismutase-and catalase-like activities capable of effective scavenging of ROS.In addition,anti-inflammatory effects are mediated by controlled,on-demand near-infrared-triggered ALO release leading to inhibition of COX-2 expression.Importantly,the combined therapy can promote the polarization of macrophages to the M2 subtype by upregulating Arg-1 and CD206 expression and downregulating expression of TNF-α,IL-1βand IL-6,thereby inhibiting atherosclerosis-related foam cell formation.In conclusion,the presented in vitro and in vivo data demonstrate that Pd@HA/ALO enhanced macrophage polarization to reduce plaque formation,identifying an attractive treatment strategy for cardiovascular disease.展开更多
A series of Ag,Cu and Co-doped manganese oxide octahedral molecular sieves(OMS-2) were synthesized and evaluated to remove nitrogen oxides(NOx) from cigarette mainstream smoke.The three kinds of catalysts were added t...A series of Ag,Cu and Co-doped manganese oxide octahedral molecular sieves(OMS-2) were synthesized and evaluated to remove nitrogen oxides(NOx) from cigarette mainstream smoke.The three kinds of catalysts were added to cigarettes for studying the capabilities of reducing NOx from cigarette mainstream smoke.The catalysis and reduction of NO in laboratory were studied.A mechanism for NOx catalytic reduction from burning cigarettes with the catalysts adding to cigarettes was described.The catalysts show excellent catalytic activity for NOx removal,especially the Ag-doped OMS-2 catalyst.0.5%(mass fraction) Ag-doped OMS-2 catalyst has the best ability to remove NOx from cigarette mainstream smoke.The use of Ag-doped OMS-2 as catalyst for removing carcinogenic compounds from cigarette smoke will be an effective strategy to protect the environment and public health.展开更多
Homogeneous hollow Cu20 octahedral nanostructures have been fabricated by a facile onepot reduction reaction at roomtemperature. The microscope analysis revealed that the edges of as-prepared hollow structures were ar...Homogeneous hollow Cu20 octahedral nanostructures have been fabricated by a facile onepot reduction reaction at roomtemperature. The microscope analysis revealed that the edges of as-prepared hollow structures were around 200 nm with a wall thickness of about 20 nm. To investigate the influence factors and formation mechanism of the hollow octahedral structure, samples subjected to different reaction conditions were studies. The results showed that the morphology and structures of Cu20 particles were greatly affected by the concentration of pH value of the reaction environment and the reaction time. Ostwald ripening process is orooosed to exolain the growth mechanism of the hollow octahedral nanostructures.展开更多
Using an effective field theory with correlations, magnetic properties of an octahedral chain described by a mixed spin Ising model are investigated. Unique phenomena such as multiple hysteresis loops, saturation magn...Using an effective field theory with correlations, magnetic properties of an octahedral chain described by a mixed spin Ising model are investigated. Unique phenomena such as multiple hysteresis loops, saturation magnetization, and reverse flip of the magnetization plateaus occur when certain typical parameters are applied. These results may be helpful to further investigate the magnetic properties of one-dimensional systems and could potentially be utilized in the design of spin devices.展开更多
The tremendous potential of triboelectric generators-TENGs for converting mechanical energy into electrical energy places them as one of the most promising energy harvesting technologies. In this work, the fabrication...The tremendous potential of triboelectric generators-TENGs for converting mechanical energy into electrical energy places them as one of the most promising energy harvesting technologies. In this work, the fabrication of enhanced performance TENGs using Ag octahedron nano-assemblies on ITO as electrodes significantly increases the electric charge collection of the induced tribocharges. Thereby, nanostructured electrical contacts coated with Ag macroscale nano-assemblies with octahedral features were obtained by the electrodeposition technique on flexible PET/ITO substrates. Consequently, the nanostructured triboelectric generator-TENG exhibited 65 times more maximum output power, and almost 10 times more open circuit output voltage than that of a TENG with non-nanostructured contacts passing from μW to m W capabilities, which was attributed to the increment of intrinsic interface states due to a higher effective contact area in the former. Likewise, output performances of TENGs also displayed an asymptotic behavior on the output voltage as the operating frequency of the mechanical oscillations increased, which is attributed to a decrement in the internal impedance of the device with frequency. Furthermore, it is shown that the resulting electrical output power can successfully drive low power consumption electronic devices. On that account, the present research establishes a promising platform which contributes in an original way to the development of the TENGs technology.展开更多
The structural, magnetic and electronic properties of the double perovskite Ba2SmNbO6 （for the simple cubic structure where no octahedral tilting exists anymore） are studied using the density functional theory withi...The structural, magnetic and electronic properties of the double perovskite Ba2SmNbO6 （for the simple cubic structure where no octahedral tilting exists anymore） are studied using the density functional theory within the generalized gradient approximation as well as taking into account the on-site Coulomb repulsive interaction. The total energy, the spin magnetic moment, the band structure and the density of states are calculated. The optimization of the lattice constants is 8.5173 A, which is in good agreement with the experimental value 8.5180 A. The calculations reveal that Ba2SmNbO6 has a stable ferromagnetic ground state and the spin magnetic moment per molecule is 5.00μB/f.u. which comes mostly from the Sin3＋ ion only. By analysis of the band structure, the compound exhibits the direct band gap material and half-metallic ferromagnetic nature with 100% spin-up polarization, which implies potential applications of this new lanthanide compound in magneto-electronic and spintronic devices.展开更多
Octahedral CoO with nanostructures decorated with Ag nanoparticles was prepared via a facile solvothermal approach. After being annealed at 500 ℃ for 1 h, an electrochemical capacitor material of Co3O4 decorated with...Octahedral CoO with nanostructures decorated with Ag nanoparticles was prepared via a facile solvothermal approach. After being annealed at 500 ℃ for 1 h, an electrochemical capacitor material of Co3O4 decorated with Ag2O was obtained. The cyclic voltammetry and galvanostatic charge-discharge were used to evaluate the electrochemical properties of the as-prepared products. The results indicated that the as-prepared samples exhibited fine pseudo-capacitive performance, and the surface modifications of Ag2O can significantly increase the capacitance of the Co3O4 material. The specific capacitance of Ag2O/Co3O4 composite electrode was up to 217.6 F·g^-1, which was 3.35 times as high as that of pure Co3O4. Moreover, Ag2O/Co3O4 composite showed an excellent cycle performance, and 65.3% of specific capacitance was maintained after 200 cycles.展开更多
Recycling spent lithium-ion batteries is essential for alleviating resource shortages and environmental pollution,with cathode material recovery being especially significant due to its high content of valuable element...Recycling spent lithium-ion batteries is essential for alleviating resource shortages and environmental pollution,with cathode material recovery being especially significant due to its high content of valuable elements.Relithiation is crucial for the direct regeneration of spent cathodes,and defective structures(Li vacancies,spinel/rock salt)in layered cathodes can only be completely repaired in an environment with adequate Li.However,cathode materials recycled by relithiation suffer the formation of dense spinel/rock salt structure,induced by the migration of transition metals(TMs)to the Li layer and resulting in the creation of TMO_(6)octahedron,which hinders Li^(+)transport between adjacent LiO_(4)tetrahedra,and further greatly impedes the relithiation of the spent cathodes.Here,we regulated lattice stress at the defect structures to break the lattice symmetry of the unfavorable TMO_(6)octahedron and consequently form a quasi LiO_(6)octahedral sites with a low Li^(+)transport energy barrier.This approach ensures a Li-sufficient environment,facilitating the effective relithiation and structural repair of spent cathodes.The combination of theoretical calculations and experimental approaches proves the advantage of symmetry breaking over the traditional relithiation process in repairing the structure of spent cathodes.The proposed repair strategy paves the way for the exploration of more efficient repair methods for spent cathode materials.展开更多
In this study,the truncated octahedral CeO_(2)(CeO_(2)-to)with special morphology was prepared by the solvothermal method with oleic acid(OA)and oleamine(OM)as the morphology-directing agents.High-resolution transmiss...In this study,the truncated octahedral CeO_(2)(CeO_(2)-to)with special morphology was prepared by the solvothermal method with oleic acid(OA)and oleamine(OM)as the morphology-directing agents.High-resolution transmission electron microscopy(HRTEM)results show that CeO_(2)-to exposes composite{100}and{111}facets,while CeO_(2)cubic(CeO_(2)-c)and CeO_(2)octahedral(CeO_(2)-o)only expose single crystal facets of{100}plane and{111}plane,respectively.Interestingly,this CeO_(2)-to photocatalyst exhibits remarkable photooxidation performance of gaseous acetaldehyde(CH_(3)CHO)degradation,in which CO_(2)generation value reaches 1.78 and 7.97-times greater than that of CeO_(2)-c and CeO_(2)-o,respectively.In addition,the active species trapping experiment signifies that superoxide(·O_(2)^(-))and holes(h^(+))are the main reactive substances during the CH_(3)CHO degradation process,and the electron paramagnetic resonance(EPR)spectra indicates that the former is the major contributor.Notably,the electron transfer mechanism between CeO_(2)-to{100}and{111}facets and the surface oxygen adsorption ability are revealed via density functional theory(DFT)calculations.It is also confirmed that{100}facets are more conducive to the absorption of acetaldehyde than{111}facets.Finally,a reasonable mechanism for improved photocatalytic CH_(3)CHO degradation on CeO_(2)-to is proposed based on relevant experiments and DFT calculations.This study demonstrates that the systematic development of surface homojunction structured photocatalysts can efficiently increase the degradation activity for volatile organic compounds(VOCs).It also offers additional direction for optimizing the photocatalytic activity of other ceriumbased photocatalysts.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
Pt-based magnetic nano catalysts are one of the most suitable cand idates for electrocatalytic materials due to their high electrochemistry activity and retrievability.Unfortunately,the inferior durability prevents th...Pt-based magnetic nano catalysts are one of the most suitable cand idates for electrocatalytic materials due to their high electrochemistry activity and retrievability.Unfortunately,the inferior durability prevents them from being scaled-up,limiting their commercial applications.Herein,an antiferromagnetic element Mn was introduced into PtCo nanostructured alloy to synthesize uniform Mn-PtCo truncated octahedral nanoparticles(TONPs)by one-pot method.Our results show that Mn can tune the blocking temperature of Mn-PtCo TONPs due to its an tiferromag netism.At low temperatures,Mn-PtCo TONPs are ferromag netic,and the coercivity in creases gradually with in creasi ng Mn contents.At room temperature,the Mn-PtCo TONPs display superparamag netic behavior,which is greatly helpful for in dustrial recycling.Mn doping can not only modify the electronic structure of PtCo TONPs but also enhanee electrocatalytic performance for methanol oxidation reaction.The maximum specific activity of Mn-PtCo-3 reaches 8.1 A`m^-2,3.6 times of commercial Pt/C(2.2 A·m^-2)and 1.4 times of PtCo TONPs(5.6 A`m^-2),respectively.The mass activity decreases by only 30%after 2,000 cycles,while it is 45%and 99%(nearly inactive)for PtCo TONPs and commercial Pt/C catalysts,respectively.展开更多
Submicrometer sized pure cubic phase,Eu^(3+)doped,and Yb^(3+)/Er^(3+)co-dopedα-NaYF4 particles with octahedral morphology have been prepared in acetic acid.The acetate anion plays a critical role in the formation of ...Submicrometer sized pure cubic phase,Eu^(3+)doped,and Yb^(3+)/Er^(3+)co-dopedα-NaYF4 particles with octahedral morphology have been prepared in acetic acid.The acetate anion plays a critical role in the formation of such symmetric octahedral structures through its selective adsorption on the(111)faces of the products.The size of the as-prepared octahedra can be tuned by varying the amount of sodium acetate added to the acetic acid.A possible formation mechanism for these octahedra has been proposed.The dopedα-NaYF_(4) octahedral submicrometer particles show down-conversion and up-conversion photoluminescence typical of these materials.展开更多
The synthesis of surface composition-tunable Pt-based octahedral nanoalloys is key to unravel the structureproperty relationship in fuel cells. Herein, we report a facile route to prepare composition-tunable Pt Cu oct...The synthesis of surface composition-tunable Pt-based octahedral nanoalloys is key to unravel the structureproperty relationship in fuel cells. Herein, we report a facile route to prepare composition-tunable Pt Cu octahedral nanoalloys by using halogen ions(Br-or/and I-) as composition modulators. Among these Pt Cu octahedral nanoalloys,Pt59 Cu41 octahedron exhibits the highest catalytic activity and durability in alkaline solution. The specific activity/mass activity of Pt59 Cu41 octahedron is 20.25 m A cm^-2/3.24 A mg^-1 Pt,which is 6.64/5.3 times higher than commercial Pt black in 0.5 mol L^-1 CH3 OH, respectively. In the case of using ethanol(0.5 mol L^-1) as fuel source, Pt59 Cu41 octahedron shows much better catalytic activity, that is 34.84 m A cm^-2/5.58 A mg^-1 Pt for specific activity/mass activity, which is 9.16/7.34 times higher than commercial Pt black, respectively. In situ Fourier transform infrared spectroscopy is employed to detect the intermediate species and products for methanol/ethanol oxidation reaction and a plausible mechanism is proposed to explain the improved activity and durability of Pt59 Cu41 octahedron toward methanol/ethanol oxidation in alkaline medium.展开更多
Halide perovskites have attracted tremendous attention as semiconducting materials for various optoelectronic applications.The functional metal-halide octahedral units and their spatial arrangements play a key role in...Halide perovskites have attracted tremendous attention as semiconducting materials for various optoelectronic applications.The functional metal-halide octahedral units and their spatial arrangements play a key role in the optoelectronic properties of these materials.At present,most of the efforts for material exploration focus on substituting the constituent elements of functional octahedral units,whereas designing the spatial arrangement of the functional units has received relatively little consideration.In this work,via a global structure search based on density functional theory(DFT),we discovered a metastable three-dimensional honeycomb-like perovskite structure with the functional octahedral units arranged through mixed edge-and comer-sharing.We experimentally confirmed that the honeycomb-like perovskite structure can be stabilized by divalent molecular cations with suitable size and shape,such as 2,2’-bisimidazole(BIM).DFT calculations and experimental characterizations revealed that the honeycomb-like perovskite with the formula of BIMPb2l6,synthesized through a solution process,exhibits high electronic dimensionality,a direct allowed bandgap of 2.1 eV,small effective masses for both electrons and holes,and high optical absorption coefficients,which indicates a significant potential for optoelectronic applications.The employed combination of DFT and experimental study provides an exemplary approach to explore prospective optoelectronic semiconductors via spatially arranging functional units.展开更多
基金support from the Natural Science Foundation of Jiangsu Province(BK20220596)Innovative science and technology platform project of cooperation between Yangzhou City and Yangzhou University,China(No.YZ202026305)+1 种基金Natural Science Foundation of China(21922202,21673202 and 22272147)the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘Intergrowth ferroelectric semiconductors with excellent spontaneous polarization field are highly promising piezo-photocatalytic candidate materials.In addition,developing structural design and revealing polarization enhancement in-depth mechanism are top priorities.Herein,we introduce the intergrowth ferroelectrics Bi_(7)Ti_(4)NbO_(21)thin-layer nanosheets for piezo-photocatalytic CO_(2)reduction.Density functional theory(DFT)calculations indicate that interlayer lattice mismatch leads to increased tilting and rotation angle of Ti/NbO_(6)octahedra on perovskite-like layers,serving as the main reason for increased polarization.Furthermore,the tilting and rotation angle of the interlayer octahedron further increase under stress,suggesting a stronger driving force generated to facilitate charge carrier separation efficiency.Meanwhile,Bi_(7)Ti_(4)NbO_(21)nanosheets provide abundant active sites to effectively adsorb CO_(2)and acquire sensitive stress response,thereby presenting synergistically advanced piezo-photocatalytic CO_(2)reduction activity with a high CO generation rate of 426.97μmol g^(-1)h^(-1).Our work offers new perspectives and directions for initiating and investigating the mechanisms of high-performance intergrowth piezo-photocatalysts.
基金Funded by the Nation Natural Science Foundation of China(No.52304410)the Science Fund for Creative Research Groups of the National Natural Science Foundation of Hubei Province(No.2020CFA038)+2 种基金the Major Project of Hubei Province(Functional coating and materials,No.2023BAA003)the State Key Laboratory of Coking Coal Resources Green Exploitation(No.41040220201308)the Research Project of Yingcheng Xinjincheng Environmental Protection Technology Co.,Ltd(No.2023420612000754)。
文摘Octahedral Fe_(3)O_(4)-modified coke Fenton catalyst(Fe_(3)O_(4)/PCWQ)was prepared via in-situ one-pot oxidation method inspired by grapefruit peel,and characterized by SEM,EDS,XRD,XPS,FTIR,BET,VSM,and Raman,respectively.Fe_(3)O_(4)crystals was predominantly in octahedral morphology with an average particle size of 60 nm.Fe_(3)O_(4)/PCWQ exhibited graphene-like structure.The synergistic effect between oxygen functional group and Fe^(2+)/Fe^(3+)cycle in Fe_(3)O_(4)/PCWQ enhances the degradation performance of p-nitrophenol(P-NP).Under the optimal conditions(1.0 g/L catalyst,30 mmol/L H_(2)O_(2),pH 3.0,25℃),Fe_(3)O_(4)/PCWQ exhibits high degradation efficiency of P-NP(91.25%in 30 min and 98.21%in 180 min)and stability(90.72%after 6 cycles)with low iron leaching(<0.528 mg/L),following the quasi-first-order degradation kinetics.Fe_(3)O_(4)/PCWQ has better catalytic performance than pure Fe_(3)O_(4)under the action of H_(2)O_(2),and is an efficient,stable and repeatable green catalyst.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.52322212,52025025,5225040212474001)the National Key R&D Program of China(Grant Nos.2022YFA1403203 and 2023YFA1406300)。
文摘Topochemical fluorination introduces significant structural distortions and emerging properties in perovskite oxides via substituting oxygen with fluorine.However,the rapid fluorination process and the similarity between F and O render the O/F site occupation and local lattice evolution during fluorination unclear.Here we investigated the atomic-scale O/F exchange in La2CoO4and quantified the lattice distortion of three ordered structures:La_(2)CoO_(3.5)F,La_(2)CoO_(3)F_(2),and La_(2)CoO_(2.5)F_(3)by utilizing aberration-corrected electron microscopy.Atomic-resolved elemental mapping provides direct evidence for the O/F occupancy in interstitial and apical sites.We revealed that apical F ions induce significant octahedral tilting from 178°to 165°,linearly proportional to the occupancy rate;and cause the obvious change in the fine structure O K edge,meanwhile apical O is exchanged into interstitial sites.The strong octahedral tilt leads to the in-plane elongation of the[CoO_(4)F_(2)]octahedra.These findings elucidate the atomic-scale mechanisms of the entire fluorination process and highlight the significant role of F in tuning the octahedral tilt of functional oxides.
基金supported by the National Natural Science Foundation of China(Nos.21972073,22136003,22206188,and 21805166).
文摘Advanced processes for peroxymonosulfate(PMS)-based oxidation are efficient in eliminating toxic and refractory organic pol-lutants from sewage.The activation of electron-withdrawing HSO_(5)^(-)releases reactive species,including sulfate radical(·SO_(4)^(-)),hydroxyl radical(·OH),superoxide radical(·O_(2)^(-)),and singlet oxygen(1O_(2)),which can induce the degradation of organic contaminants.In this work,we synthesized a variety of M-OMS-2 nanorods(M=Co,Ni,Cu,Fe)by doping Co^(2+),Ni^(2+),Cu^(2+),or Fe^(3+)into manganese oxide oc-tahedral molecular sieve(OMS-2)to efficiently remove sulfamethoxazole(SMX)via PMS activation.The catalytic performance of M-OMS-2 in SMX elimination via PMS activation was assessed.The nanorods obtained in decreasing order of SMX removal rate were Cu-OMS-2(96.40%),Co-OMS-2(88.00%),Ni-OMS-2(87.20%),Fe-OMS-2(35.00%),and OMS-2(33.50%).Then,the kinetics and struc-ture-activity relationship of the M-OMS-2 nanorods during the elimination of SMX were investigated.The feasible mechanism underly-ing SMX degradation by the Cu-OMS-2/PMS system was further investigated with a quenching experiment,high-resolution mass spec-troscopy,and electron paramagnetic resonance.Results showed that SMX degradation efficiency was enhanced in seawater and tap water,demonstrating the potential application of Cu-OMS-2/PMS system in sewage treatment.
基金supported by the National Natural Science Foundation of China(2137704421573085)+5 种基金the Key Project of Natural Science Foundation of Hubei Province(2015CFA037)Wuhan Planning Project of Science and Technology(2014010101010023)Self-determined Research Funds of CCNU from the Colleges’Basic Research and Operation of MOE(CCNU15ZD007CCNU15KFY005)China Postdoctoral Science Foundation(2015M572187)Hubei Provincial Department of Education(D20152702)~~
文摘A photocatalyst composed of TiO 2 nanotube arrays（TNTs） and octahedral Cu2 O nanoparticles was fabricated,and its performance in the photocatalytic reduction of CO2 under visible and simulated solar irradiation was studied. The average nanotube diameter and length was 100 nm and 5 μm,respectively. The different amount of octahedral Cu2 O modified TNTs were obtained by varying electrochemical deposition time. TNTs modified with an optimized amount of Cu2 O nanoparticles exhibited high efficiency in the photocatalysis,and the predominant hydrocarbon product was methane. The methane yield increased with increasing Cu2 O content of the catalyst up to a certain deposition time,and decreased with further increase in Cu2 O deposition time. Insufficient deposition time（5 min） resulted in a small amount of Cu2 O nanoparticles on the TNTs,leading to the disadvantage of harvesting light. However,excess deposition time（45 min） gave rise to entire TNT surface being most covered with Cu2 O nanoparticles with large sizes,inconvenient for the transport of photo-generated carriers. The highest methane yield under simulated solar and visible light irradiation was observed for the catalysts prepared at a Cu2 O deposition time of 15 and 30 min respectively. The morphology,crystallization,photoresponse and electrochemical properties of the catalyst were characterized to understand the mechanism of its high photocatalytic activity. The TNT structure provided abundant active sites for the adsorption of reactants,and promoted the transport of photogenerated carriers that improved charge separation. Modifying the TNTs with octahedral Cu2 O nanoparticles promoted light absorption,and prevented the hydrocarbon product from oxidation. These factors provided the Cu2O-modified TNT photocatalyst with high efficiency in the reduction of CO2,without requiring co-catalysts or sacrificial agents.
文摘Several catalysts comprising Pt supported on octahedral Fe3O4（Pt/Fe3O4） were prepared by a facile method involving co-precipitation followed by thermal treatment at different temperatures. A variety of characterization results revealed that this preparation process afforded highly crystalline octahedral Fe3O4 with a uniform distribution of Pt nanoparticles on its surface. The thermal-treatment temperature significantly influenced the redox properties of the Pt/Fe3O4 catalysts. All the Pt/Fe3O4 catalysts were found to be catalytically active and stable for the oxidation of low-concentration formaldehyde（HCHO） with oxygen. The catalyst prepared by thermal treatment at 80 °C（labelled Pt/Fe3O4-80） exhibited the highest catalytic activity, efficiently converting HCHO to CO2 and H2 O under ambient temperature and moisture conditions. The excellent performance of Pt/Fe3O4-80 was mainly attributed to beneficial interactions between the Pt and Fe species that result in the formation a higher density of active interface sites（e.g., Pt-O-FeO x and Pt-OH-FeO x）. The introduction of water vapor improves the catalytic activity of the Pt/Fe3O4 catalysts as it participates in a water-assisted dissociation process.
基金supported by the Young Elite Scientists Sponsorship Program by Tianjin(No.0701320001)the Major Special Projects(No.0402080005)+1 种基金the financial support from the CEITEC 2020 Project(No.LQ1601)the Ministry of Education,Youth and Sports of the Czech Republic under the National Sustainability ProgrammeⅡand by ERDF(No.CZ.02.1.01/0.0/0.0/16_025/0007314)。
文摘Inhibition of foam cell formation is considered a promising treatment method for atherosclerosis,the leading cause of cardiovascular diseases worldwide.However,currently available therapeutic strategies have shown unsatisfactory clinical outcomes.Thus,herein,we design aloperine(ALO)-loaded and hyaluronic acid(HA)-modified palladium(Pd)octahedral nanozymes(Pd@HA/ALO)that can synergistically scavenge reactive oxygen species(ROS)and downregulate cyclooxygenase-2(COX-2)expression to induce macrophage polarization,thus inhibiting foam cell formation to attenuate atherosclerosis.Due to the targeted effect of HA on stabilin-2 and CD44,which are overexpressed in atherosclerotic plaques,Pd@HA/ALO can actively accumulate in atherosclerotic plaques.Subsequently,the antioxidative effects of Pd octahedral nanozymes are mediated by their intrinsic superoxide dismutase-and catalase-like activities capable of effective scavenging of ROS.In addition,anti-inflammatory effects are mediated by controlled,on-demand near-infrared-triggered ALO release leading to inhibition of COX-2 expression.Importantly,the combined therapy can promote the polarization of macrophages to the M2 subtype by upregulating Arg-1 and CD206 expression and downregulating expression of TNF-α,IL-1βand IL-6,thereby inhibiting atherosclerosis-related foam cell formation.In conclusion,the presented in vitro and in vivo data demonstrate that Pd@HA/ALO enhanced macrophage polarization to reduce plaque formation,identifying an attractive treatment strategy for cardiovascular disease.
文摘A series of Ag,Cu and Co-doped manganese oxide octahedral molecular sieves(OMS-2) were synthesized and evaluated to remove nitrogen oxides(NOx) from cigarette mainstream smoke.The three kinds of catalysts were added to cigarettes for studying the capabilities of reducing NOx from cigarette mainstream smoke.The catalysis and reduction of NO in laboratory were studied.A mechanism for NOx catalytic reduction from burning cigarettes with the catalysts adding to cigarettes was described.The catalysts show excellent catalytic activity for NOx removal,especially the Ag-doped OMS-2 catalyst.0.5%(mass fraction) Ag-doped OMS-2 catalyst has the best ability to remove NOx from cigarette mainstream smoke.The use of Ag-doped OMS-2 as catalyst for removing carcinogenic compounds from cigarette smoke will be an effective strategy to protect the environment and public health.
基金Funded by the Fundamental Research Funds for the Central Universities (No.123201003)
文摘Homogeneous hollow Cu20 octahedral nanostructures have been fabricated by a facile onepot reduction reaction at roomtemperature. The microscope analysis revealed that the edges of as-prepared hollow structures were around 200 nm with a wall thickness of about 20 nm. To investigate the influence factors and formation mechanism of the hollow octahedral structure, samples subjected to different reaction conditions were studies. The results showed that the morphology and structures of Cu20 particles were greatly affected by the concentration of pH value of the reaction environment and the reaction time. Ostwald ripening process is orooosed to exolain the growth mechanism of the hollow octahedral nanostructures.
基金Project supported by National Natural Science Foundation of China(Grant No.51920105011)the Key R&D Program of Liaoning Province of China(Grant No.2020JH2/10300079)。
文摘Using an effective field theory with correlations, magnetic properties of an octahedral chain described by a mixed spin Ising model are investigated. Unique phenomena such as multiple hysteresis loops, saturation magnetization, and reverse flip of the magnetization plateaus occur when certain typical parameters are applied. These results may be helpful to further investigate the magnetic properties of one-dimensional systems and could potentially be utilized in the design of spin devices.
基金Consejo Nacional de Ciencia y Tecnología of México (CONACYT) for her Doctoral scholarshippostgraduate studies department at CIMAVMonterrey for fellowship support。
文摘The tremendous potential of triboelectric generators-TENGs for converting mechanical energy into electrical energy places them as one of the most promising energy harvesting technologies. In this work, the fabrication of enhanced performance TENGs using Ag octahedron nano-assemblies on ITO as electrodes significantly increases the electric charge collection of the induced tribocharges. Thereby, nanostructured electrical contacts coated with Ag macroscale nano-assemblies with octahedral features were obtained by the electrodeposition technique on flexible PET/ITO substrates. Consequently, the nanostructured triboelectric generator-TENG exhibited 65 times more maximum output power, and almost 10 times more open circuit output voltage than that of a TENG with non-nanostructured contacts passing from μW to m W capabilities, which was attributed to the increment of intrinsic interface states due to a higher effective contact area in the former. Likewise, output performances of TENGs also displayed an asymptotic behavior on the output voltage as the operating frequency of the mechanical oscillations increased, which is attributed to a decrement in the internal impedance of the device with frequency. Furthermore, it is shown that the resulting electrical output power can successfully drive low power consumption electronic devices. On that account, the present research establishes a promising platform which contributes in an original way to the development of the TENGs technology.
文摘The structural, magnetic and electronic properties of the double perovskite Ba2SmNbO6 （for the simple cubic structure where no octahedral tilting exists anymore） are studied using the density functional theory within the generalized gradient approximation as well as taking into account the on-site Coulomb repulsive interaction. The total energy, the spin magnetic moment, the band structure and the density of states are calculated. The optimization of the lattice constants is 8.5173 A, which is in good agreement with the experimental value 8.5180 A. The calculations reveal that Ba2SmNbO6 has a stable ferromagnetic ground state and the spin magnetic moment per molecule is 5.00μB/f.u. which comes mostly from the Sin3＋ ion only. By analysis of the band structure, the compound exhibits the direct band gap material and half-metallic ferromagnetic nature with 100% spin-up polarization, which implies potential applications of this new lanthanide compound in magneto-electronic and spintronic devices.
基金Funded by National Natural Science Foundation of China(Nos.51502005,51602005,11647001 and 11404005)Key Foundation for Young Talents in College of Anhui Province(Nos.gxyq ZD2016081,2013SQRL026ZD)Open Foundation for Cooperative Innovation Research Center for Weak Signal-Detecting Materials and Devices Integration(No.01001795-201403)
文摘Octahedral CoO with nanostructures decorated with Ag nanoparticles was prepared via a facile solvothermal approach. After being annealed at 500 ℃ for 1 h, an electrochemical capacitor material of Co3O4 decorated with Ag2O was obtained. The cyclic voltammetry and galvanostatic charge-discharge were used to evaluate the electrochemical properties of the as-prepared products. The results indicated that the as-prepared samples exhibited fine pseudo-capacitive performance, and the surface modifications of Ag2O can significantly increase the capacitance of the Co3O4 material. The specific capacitance of Ag2O/Co3O4 composite electrode was up to 217.6 F·g^-1, which was 3.35 times as high as that of pure Co3O4. Moreover, Ag2O/Co3O4 composite showed an excellent cycle performance, and 65.3% of specific capacitance was maintained after 200 cycles.
基金the support from the National Natural Science Foundation of China(22278329,92472124)the High-level Innovation and Entrepreneurship Talent Project of Qinchuangyuan(OCYRCXM-2022-308)+4 种基金the State Key Laboratory for Electrical Insulation and Power Equipment(EIPE23125)the“Young Talent Support Plan”of Xi'an Jiaotong Universitythe Postdoctoral Innovation Talents Support Program(BX20230291)the China Postdoctoral Science Foundation(2024M762607)the Shaanxi Province Postdoctoral Research Funding Program。
文摘Recycling spent lithium-ion batteries is essential for alleviating resource shortages and environmental pollution,with cathode material recovery being especially significant due to its high content of valuable elements.Relithiation is crucial for the direct regeneration of spent cathodes,and defective structures(Li vacancies,spinel/rock salt)in layered cathodes can only be completely repaired in an environment with adequate Li.However,cathode materials recycled by relithiation suffer the formation of dense spinel/rock salt structure,induced by the migration of transition metals(TMs)to the Li layer and resulting in the creation of TMO_(6)octahedron,which hinders Li^(+)transport between adjacent LiO_(4)tetrahedra,and further greatly impedes the relithiation of the spent cathodes.Here,we regulated lattice stress at the defect structures to break the lattice symmetry of the unfavorable TMO_(6)octahedron and consequently form a quasi LiO_(6)octahedral sites with a low Li^(+)transport energy barrier.This approach ensures a Li-sufficient environment,facilitating the effective relithiation and structural repair of spent cathodes.The combination of theoretical calculations and experimental approaches proves the advantage of symmetry breaking over the traditional relithiation process in repairing the structure of spent cathodes.The proposed repair strategy paves the way for the exploration of more efficient repair methods for spent cathode materials.
基金supported by the National Natural Science Foundation of China(Nos.21805191 and 22205084)Project funded by China Postdoctoral Science Foundation(No.2023M741039)+3 种基金Project funded by National&Local Joint Engineering Research Center for Mineral Salt Deep Utilization(SF202303)Project Funded by Yangzhou University(137013308),Guangdong Basic and Applied Basic Research Foundation(No.2020A1515010982)Shenzhen Stable Support Project(No.20200812122947002),the Innovative Science and Technology Platform Project of Cooperation between Yangzhou City and Yangzhou UniversityPostgraduate Research&Practice Innovation Program of Jiangsu Province(Yangzhou University,No.XKYCX20_014)。
文摘In this study,the truncated octahedral CeO_(2)(CeO_(2)-to)with special morphology was prepared by the solvothermal method with oleic acid(OA)and oleamine(OM)as the morphology-directing agents.High-resolution transmission electron microscopy(HRTEM)results show that CeO_(2)-to exposes composite{100}and{111}facets,while CeO_(2)cubic(CeO_(2)-c)and CeO_(2)octahedral(CeO_(2)-o)only expose single crystal facets of{100}plane and{111}plane,respectively.Interestingly,this CeO_(2)-to photocatalyst exhibits remarkable photooxidation performance of gaseous acetaldehyde(CH_(3)CHO)degradation,in which CO_(2)generation value reaches 1.78 and 7.97-times greater than that of CeO_(2)-c and CeO_(2)-o,respectively.In addition,the active species trapping experiment signifies that superoxide(·O_(2)^(-))and holes(h^(+))are the main reactive substances during the CH_(3)CHO degradation process,and the electron paramagnetic resonance(EPR)spectra indicates that the former is the major contributor.Notably,the electron transfer mechanism between CeO_(2)-to{100}and{111}facets and the surface oxygen adsorption ability are revealed via density functional theory(DFT)calculations.It is also confirmed that{100}facets are more conducive to the absorption of acetaldehyde than{111}facets.Finally,a reasonable mechanism for improved photocatalytic CH_(3)CHO degradation on CeO_(2)-to is proposed based on relevant experiments and DFT calculations.This study demonstrates that the systematic development of surface homojunction structured photocatalysts can efficiently increase the degradation activity for volatile organic compounds(VOCs).It also offers additional direction for optimizing the photocatalytic activity of other ceriumbased photocatalysts.
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The work was supported by the National Natural Science Foundation(Nos.51625101,51431009,5180118&and 51701202)the State Key Development Program for Basic Research of China(No.2015CB921401)+3 种基金the Fundamental Research Funds for the Central University Universities of China(No.FRF-TP-16-001C2)the China Postdoctoral Science Foundation(No.2018M632792)Startup Research Fund of Zhengzhou University(No.32210815)Bejing Natural Science Foundation(No.Z180014).
文摘Pt-based magnetic nano catalysts are one of the most suitable cand idates for electrocatalytic materials due to their high electrochemistry activity and retrievability.Unfortunately,the inferior durability prevents them from being scaled-up,limiting their commercial applications.Herein,an antiferromagnetic element Mn was introduced into PtCo nanostructured alloy to synthesize uniform Mn-PtCo truncated octahedral nanoparticles(TONPs)by one-pot method.Our results show that Mn can tune the blocking temperature of Mn-PtCo TONPs due to its an tiferromag netism.At low temperatures,Mn-PtCo TONPs are ferromag netic,and the coercivity in creases gradually with in creasi ng Mn contents.At room temperature,the Mn-PtCo TONPs display superparamag netic behavior,which is greatly helpful for in dustrial recycling.Mn doping can not only modify the electronic structure of PtCo TONPs but also enhanee electrocatalytic performance for methanol oxidation reaction.The maximum specific activity of Mn-PtCo-3 reaches 8.1 A`m^-2,3.6 times of commercial Pt/C(2.2 A·m^-2)and 1.4 times of PtCo TONPs(5.6 A`m^-2),respectively.The mass activity decreases by only 30%after 2,000 cycles,while it is 45%and 99%(nearly inactive)for PtCo TONPs and commercial Pt/C catalysts,respectively.
基金by the National Basic Research Program of China(2007CB925101)National Science Foundation of China(20671087).
文摘Submicrometer sized pure cubic phase,Eu^(3+)doped,and Yb^(3+)/Er^(3+)co-dopedα-NaYF4 particles with octahedral morphology have been prepared in acetic acid.The acetate anion plays a critical role in the formation of such symmetric octahedral structures through its selective adsorption on the(111)faces of the products.The size of the as-prepared octahedra can be tuned by varying the amount of sodium acetate added to the acetic acid.A possible formation mechanism for these octahedra has been proposed.The dopedα-NaYF_(4) octahedral submicrometer particles show down-conversion and up-conversion photoluminescence typical of these materials.
基金supported by the National Natural Science Foundation of China (21571038 and 21361005)the Open Fund of the Key Lab of Organic Optoelectronics & Molecular Engineering (Tsinghua University)+1 种基金the Foundation for Excellent Young Scientific and Technological Talents of Guizhou Province (2019-5666)the Special Fund for Natural Science of Guizhou University (201801)
文摘The synthesis of surface composition-tunable Pt-based octahedral nanoalloys is key to unravel the structureproperty relationship in fuel cells. Herein, we report a facile route to prepare composition-tunable Pt Cu octahedral nanoalloys by using halogen ions(Br-or/and I-) as composition modulators. Among these Pt Cu octahedral nanoalloys,Pt59 Cu41 octahedron exhibits the highest catalytic activity and durability in alkaline solution. The specific activity/mass activity of Pt59 Cu41 octahedron is 20.25 m A cm^-2/3.24 A mg^-1 Pt,which is 6.64/5.3 times higher than commercial Pt black in 0.5 mol L^-1 CH3 OH, respectively. In the case of using ethanol(0.5 mol L^-1) as fuel source, Pt59 Cu41 octahedron shows much better catalytic activity, that is 34.84 m A cm^-2/5.58 A mg^-1 Pt for specific activity/mass activity, which is 9.16/7.34 times higher than commercial Pt black, respectively. In situ Fourier transform infrared spectroscopy is employed to detect the intermediate species and products for methanol/ethanol oxidation reaction and a plausible mechanism is proposed to explain the improved activity and durability of Pt59 Cu41 octahedron toward methanol/ethanol oxidation in alkaline medium.
基金the National Natural Science Foundation of China (NSFC) (Grant No. 51972130)Startup Fund of Huazhong University of Science and Technology, and Director Fund of Wuhan National Laboratory for Optoelectronics.
文摘Halide perovskites have attracted tremendous attention as semiconducting materials for various optoelectronic applications.The functional metal-halide octahedral units and their spatial arrangements play a key role in the optoelectronic properties of these materials.At present,most of the efforts for material exploration focus on substituting the constituent elements of functional octahedral units,whereas designing the spatial arrangement of the functional units has received relatively little consideration.In this work,via a global structure search based on density functional theory(DFT),we discovered a metastable three-dimensional honeycomb-like perovskite structure with the functional octahedral units arranged through mixed edge-and comer-sharing.We experimentally confirmed that the honeycomb-like perovskite structure can be stabilized by divalent molecular cations with suitable size and shape,such as 2,2’-bisimidazole(BIM).DFT calculations and experimental characterizations revealed that the honeycomb-like perovskite with the formula of BIMPb2l6,synthesized through a solution process,exhibits high electronic dimensionality,a direct allowed bandgap of 2.1 eV,small effective masses for both electrons and holes,and high optical absorption coefficients,which indicates a significant potential for optoelectronic applications.The employed combination of DFT and experimental study provides an exemplary approach to explore prospective optoelectronic semiconductors via spatially arranging functional units.
