The interdependence of electrical parameters has long inhibited the progress of bismuth telluride(Bi_(2)Te3),limiting its widespread application in thermoelectric cooling and power generation.This work investigates th...The interdependence of electrical parameters has long inhibited the progress of bismuth telluride(Bi_(2)Te3),limiting its widespread application in thermoelectric cooling and power generation.This work investigates the n-type Bi_(2)Te_(2.79)Se_(0.21)I_(0.004)(Bi_(2)(Te,Se)_(3),BTS)system with light Zn doping,revealing that Zn addition simultaneously enhances the Seebeck coefficient(S)and electrical conductivity(σ)through the modulation of defect composition and multi-level band regulation.The substitution of Zn atoms at Bi sites enhances S via bandgap(E_(g))widening,band flattening,and band splitting effects,contributing to a competitive power factor(PF)of∼60μW⋅cm^(−1)⋅K^(−2).Additionally,thermal conductivity is maintained at a low level,leading to an extraordinary figure-of-merit(ZT)value of∼1.3 at room temperature.Furthermore,the Bi_(2)Zn_(0.01)Te_(2.79)Se_(0.21)I_(0.004) system demonstrates impressive thermoelectric device performance,with a maximum cooling temperature difference(ΔT_(max))of∼70.0 K at 300 K,rising to∼78.0 K at 323 K and∼85.7 K at 343 K,as well as a maximum conversion efficiency(η_(max))of∼6.2%under aΔT of 200 K.This study clarifies the mechanism of Zn doping and presents a cost-effective strategy for enhancing the performance of n-type BTS thermoelectrics and their devices.展开更多
Efficient photocatalytic CO_(2)reduction to valuable fuels is an ideal strategy for addressing the energy and environmental crisis.Herein,we developed the Zn-incorporated hollow nanocages,assembled by NiCo-layered dou...Efficient photocatalytic CO_(2)reduction to valuable fuels is an ideal strategy for addressing the energy and environmental crisis.Herein,we developed the Zn-incorporated hollow nanocages,assembled by NiCo-layered double hydroxide ultrathin nanosheets(NiCoZnx-LDH),as highly efficient photocatalysts.Spectroscopic characterization and theoretical calculations demonstrate that Zn doping leads to an upshift of the d-band center of Ni-Co dual sites,increasing unoccupied antibonding orbitals and enhancing the binding strength of adsorbates.Therefore,NiCoZn_(0.10)-LDH with the upgrade of d-band shows a lower·CO_(2)-formation energy,resulting in a more effective stabilization of the rate-limiting·CO_(2)-intermediate.This boosts the overall CO_(2)photoreduction performance over NiCoZn_(0.10)-LDH,resulting in a high CO yield of 158.1μmol·g^(-1)·h^(-1)with 92.1%selectivity.Our findings enrich the fundamental understanding of the CO_(2)activation mechanism and provide additional insights into the d-band center theory to enhance the photocatalytic activity for overall CO_(2)reduction.展开更多
The thermoelectric performance of CdO ceramics was enhanced by simultaneously optimizing the electrical and thermal transport properties via a small amount of Zn doping （≤3%）. The introduction of Zn can obviously i...The thermoelectric performance of CdO ceramics was enhanced by simultaneously optimizing the electrical and thermal transport properties via a small amount of Zn doping （≤3%）. The introduction of Zn can obviously increase the electrical conductivity of CdO due to the simultaneous increase of carrier concentration and mobility, and eventually results in an improvement in power factor. Zn doping is also effective in suppressing the thermal conductivity of CdO because of stronger phonon scatterings from point defects, Zn-riched second phase, and grain boundaries. A best ZT of about 0.45 has been achieved in the Cd1-xZnxO systems at about 1000 K, which is comparable to the highest values reported for other n-type oxide TE materials.展开更多
To optimize the electronic structure of photocatalyst,a facile one‐step approach is developed for the simultaneous realization of Zn‐doping and surface oxygen vacancies(SOVs)formation on SnO_(2).The Zn‐doped SnO_(2...To optimize the electronic structure of photocatalyst,a facile one‐step approach is developed for the simultaneous realization of Zn‐doping and surface oxygen vacancies(SOVs)formation on SnO_(2).The Zn‐doped SnO_(2)with abundant SOVs exhibits efficient and stable performance for photocatalytic degradation of toluene under both low and high relative humidity.Experimental and theoretical calculations results show that the synergistic effects of Zn‐doping and SOVs on SnO_(2)can considerably boost the charge transfer and separation efficiency.Utilizing the in situ DRIFTS and theoretical calculations methods,it is revealed that the benzene ring of toluene is opened at benzoic acid on the SnO_(2)surface and selectively at benzaldehyde on the Zn‐doped SnO_(2)surface.This implies that Zn‐doped SnO_(2)photocatalysts shorten the pathway of toluene degradation,and toxic intermediates can be significantly inhibited.This work could provide a promising and sustainable route for safe and efficient removal of aromatic VOCs with photocatalytic technology.展开更多
The poor film formation of Cd Se/Zn S quantum dots(QDs) during spin-coating makes a substantial impact on the device performance of quantum dot light-emitting diodes(QLEDs). This work proposes a method to improve the ...The poor film formation of Cd Se/Zn S quantum dots(QDs) during spin-coating makes a substantial impact on the device performance of quantum dot light-emitting diodes(QLEDs). This work proposes a method to improve the morphology of the quantum dot light-emitting layer(EML) by adding small organic molecular 4,4'-Bis(9 H-carbazol-9-yl) biphenyl(CBP) into the layer. Its surface roughness reduces from 6.21 nm to 2.71 nm, which guarantees a good contact between hole transport layer(HTL) and EML. Consequently, the Cd Se/Zn S QDs:CBP based QLED achieves maximum external quantum efficiency(EQE) of 5.86%, and maximum brightness of 10 363 cd/m^(2). It is demonstrated that the additive of small organic molecules could be an effective way to improve the brightness and the efficiency of QLEDs.展开更多
Low cost co-precipitation method was used to synthesize Cu(0-0.05)doped MgO samples with fixed concertation of Zn=0.01.X-ray diffraction(XRD)spectra confirmed the phase purity of the samples for 0≤Cu≤0.03 doping con...Low cost co-precipitation method was used to synthesize Cu(0-0.05)doped MgO samples with fixed concertation of Zn=0.01.X-ray diffraction(XRD)spectra confirmed the phase purity of the samples for 0≤Cu≤0.03 doping concentration.The secondary phase for 0.04≤Cu≤0.05 exhibited the formation of mixed metal oxides.The crystallite size was found to increase from 17.5 to 23.5 nm for 0≤Cu≤0.03 and then decreased from 22 to 18.5 nm for 0.04≤Cu≤0.05.The estimated bandgap first reduced from 5.48 to 4.88 eV and then increased from 5.21 to 5.36 eV.The morphology of the samples transformed from spheroidal shape to star-like shape.The obtained results reveal that the structural and optical property are in good agreement with the morphological transition.The peak shifting towards the lower values of vibrational frequency from 694 to 579 cm^(-1) confirms the incorporation of Cu/Zn in Mg-O lattice.The tuning of optical bandgap and structural properties with varying dopant concentration in MgO nanomaterials can be used for multifunctional modern energy storage and optoelectronic devices.展开更多
Zn(Ⅱ)-doped graphitic carbon nitride(g-C3N4)with high photodegradation activity was prepared by one facile step.The morphology and structure of the prepared Zn(Ⅱ)-doped g-C3N4 were investigated,and the results showe...Zn(Ⅱ)-doped graphitic carbon nitride(g-C3N4)with high photodegradation activity was prepared by one facile step.The morphology and structure of the prepared Zn(Ⅱ)-doped g-C3N4 were investigated,and the results showed that Zn(Ⅱ)could self-disperse during the pyrolysis process and Zn–N bond was formed between g-C3N4 and Zn.The dope of Zn(Ⅱ)influenced the structure of g-C3N4.The performance of photocatalytic activity of Zn(Ⅱ)-doped g-C3 N4 series indicated that the doped g-C3N4 with a small quantity of Zn(0.10 wt%)exhibits the best photocatalytic performance.The photodegradation activity for methyl orange was 2 times higher than that of pure g-C3N4.However,the photocatalytic activity decreased with the further increased content of Zn,which may be attributed to the structure change of g-C3N4 and the interaction of Zn–N bond between Zn and g-C3N4.Moreover,Zn(Ⅱ)-doped g-C3N4 showed good recycling photocatalytic stability.展开更多
In the present work,a solution-based co-precipitation method has been adopted to synthesize pure and cobalt-doped ZnS quantum dots and characterized by XRD,SEM,TEM with EDX,FTIR and gas sensing properties.XRD analysis...In the present work,a solution-based co-precipitation method has been adopted to synthesize pure and cobalt-doped ZnS quantum dots and characterized by XRD,SEM,TEM with EDX,FTIR and gas sensing properties.XRD analysis has shown a single phase of ZnS quantum dots having a zinc blend structure.TEM and XRD line broadening indicated that the average crystallite size in the sample is in the range of 2 to 5 nm.SEM micrographs show spherical-shaped quantum dots.FTIR studies show that cobalt has been successfully doped into the ZnS cubic lattice.EDX spectra have analyzed the elemental presence in the samples and it is evident that the spectra confirmed the presence of cobalt(Co),zinc(Zn),oxygen(O),and sulphur(S)elements only and no other impurities are observed.The ZnS-based quantum dot sensors reveal high sensitivity towards 50 ppm of ammonia vapors at an operating temperature of 70℃.Hence,ZnS-based quantum dots can be a promising and quick traceable sensor towards ammonia sensing applications with good response and recovery time.展开更多
Effect of divalent dopants, Zn2＋ ion, on the high-order photon avalanche （PA） upconversion （UC） emission of Er3＋ doped BiOCl microcrystals was investigated. XRD results indicated that Zn2＋ ion dopants would mos...Effect of divalent dopants, Zn2＋ ion, on the high-order photon avalanche （PA） upconversion （UC） emission of Er3＋ doped BiOCl microcrystals was investigated. XRD results indicated that Zn2＋ ion dopants would mostly enter into the lattice space at low and moderate doping concentration, and began to substitute Bi3＋ ion gradually at heavily doping level. Under exaction at 980 nm, the PA UC of violet, green and red emission of Er3＋ ions could be observed, and the UC emission intensity increased with increasing the Zn2＋ addition below 8 mol.%, then decreased with further addition. Power dependence study showed that the dopant concentration of Zn2＋ had no obviously negative effect on the occurrence of PA emission. On the bases of results investigated herein, we considered that the lattice distortion by Zn2＋ doping could not directly change the special PA emission of BiOCI：Er3＋, but would improve the emission intensity when used as lattice modifier.展开更多
Nano-scale Ni（OH）2 doped with Zn was prepared by precipitation transformation method and characterized by XRD and TEM. The electrochemical performance was investigated by cyclic voltammetry （CV） and constant curre...Nano-scale Ni（OH）2 doped with Zn was prepared by precipitation transformation method and characterized by XRD and TEM. The electrochemical performance was investigated by cyclic voltammetry （CV） and constant current technology. The measurement results indicate that the lattice parameters of nano-scale Ni（OH）2 are changed and the agglomeration of particles becomes obvious with the increased Zn-doped content. Compared with un-doped one, the discharge specific capacities ofnano-scale Ni（OH）2 doped with 10% Zn are enhanced by 8% and 6%, respectively, at the discharge rate of 0.2C and 3C. After 110 cycles, the discharge specific capacity of the sample doped with 10% zinc is still above 85% of its initial capacity discharged at 0.2C. Therefore, a suitable Zn-doped content is beneficial to improving the discharge performance of nano-scale Ni（OH）2.展开更多
CuInSe_(2)and Cu_(0.9)In_(0.9)Zn_(0.2)Se_(2)(CIZS)thin films were deposited by Radio-Frequency(RF)magnetron sputtering process.X-ray diffraction(XRD)results indicate CIZS film deposited at 300℃(CIZS-300)is(220)pre-fe...CuInSe_(2)and Cu_(0.9)In_(0.9)Zn_(0.2)Se_(2)(CIZS)thin films were deposited by Radio-Frequency(RF)magnetron sputtering process.X-ray diffraction(XRD)results indicate CIZS film deposited at 300℃(CIZS-300)is(220)pre-ferred orientation which is different from(112)preferred orientation of other films.Cu-poor and appropriate tempera-ture are major factors for(220)preferred orientation of grains.The Raman spectra show a strong peak around 171 cm1 and a weak peak around 206 cm1,which corresponding to A1 and B2 modes.Substitution of Zn for Cu leads to a broadening and blue-shift of A1 Raman mode.The band gap Eopt of CIZS film increases due to a reduced Se p-Cu d interband repulsion with Zn doping.Scanning electron microscope(SEM)measurement demonstrates that the surface morphology of CIZS is more compact and smoother than that of CIS thin films.展开更多
Zn is a frequently used and sometimes even an inevitably involved element (when zeolitic imidazolate framework-8 (ZIF-8) is adopted as the precursor) for preparing high-performance Fe-N-C oxygen reduction reaction (OR...Zn is a frequently used and sometimes even an inevitably involved element (when zeolitic imidazolate framework-8 (ZIF-8) is adopted as the precursor) for preparing high-performance Fe-N-C oxygen reduction reaction (ORR) catalysts. However, how the Zn element affects the physicochemical architecture of the catalysts, how it enhances the catalytic activity and whether Zn atoms serve as the active centers remain unclear. Herein, we proposed a novel route that adopted pyrrole as the precursor and flexibly controlled the addition of exogenous Zn and Fe dopants before pyrrole polymerization. In this way, a series of nitrogen-carbon catalysts with or without Zn or Fe doping were synthesized. The detailed characterization revealed the role of Zn and Fe doping in the catalyst morphology, pore structure, active site configurations, ORR catalytic activity and fuel cell performance. Importantly, the findings revealed that Zn doping has little effect on the ORR mechanism and pathway. It enhances ORR activity primarily by increasing the number of active sites via introducing more micro- and meso-pores, rather than by creating new active sites. While Fe doping participated in forming both pores and active site centers. Moreover, the catalyst that co-doped with Zn and Fe atoms (Zn-FeNC), synthesized via this simple and template-free route we proposed, presented a unique hollow and hierarchical pore structure with highly boosted ORR activity. It exhibited a 40 mV higher E 1/2 value than Pt/C in alkaline media, along with a rapid current response in air-cathode of the direct formate fuel cell. These results are valuable in guiding the synthesis of high-performance Fe-N-C catalysts.展开更多
Un-doped and Cu-doped ZnS（ZnS：Cu） thin films were synthesized by Successive Ion Layer Absorption and Reaction（SILAR） method. The UV–visible absorption studies have been used to calculate the band gap values of t...Un-doped and Cu-doped ZnS（ZnS：Cu） thin films were synthesized by Successive Ion Layer Absorption and Reaction（SILAR） method. The UV–visible absorption studies have been used to calculate the band gap values of the fabricated ZnS：Cu thin films. It was observed that by increasing the concentration of Cu^2＋ ions, the Fermi level moves toward the edge of the valence band of ZnS. Photoluminescence spectra of un-doped and Cu-doped ZnS thin films was recorded under 355 nm. The emission spectrum of samples has a blue emission band at 436 nm.The peak positions of the luminescence showed a red shift as the Cu^2＋ C ion concentration was increased, which indicates that the acceptor level（of Cu^2＋） is getting close to the valence band of ZnS.展开更多
Electrochemical conversion of water into oxygen and hydrogen gas is a highly efficient method to meet the energy requirement on a global scale and solve the global warming problem arising from the mass consumption of ...Electrochemical conversion of water into oxygen and hydrogen gas is a highly efficient method to meet the energy requirement on a global scale and solve the global warming problem arising from the mass consumption of fossil sources.Therefore,it is important to develop a catalyst with excellent oxygen reduction reaction(OER)activity.In this paper,we adopted the cocrystallization technology to synthesize Zn_(1-x)Co_(x)-ZIF composites.Then,the Zn_(1-x)Co_(x)-ZIF composites were used as precursors to prepare the Zn_(1-x)Co_(x)/NC electrocatalyst(NC is N-doped carbon).The influence of the Zn element on the Zn_(1-x)Co_(x)/NC electrocatalyst for the oxygen reduction reaction has been explored.All as-prepared samples were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),and X-ray photoelectron spectroscopy(XPS).The results show that Zn_(1-x)Co_(x)/NC electrocatalysts exhibit excellent OER activity.And the doping of Zn has a great influence on the structure and OER efficiency of the Zn_(1-x)Co_(x)/NC electrocatalyst.After the pyrolysis process,the organic ligands of Zn_(1-x)Co_(x)-ZIF are transformed into porous carbon and Zn and Co nanoparticles are formed inside the carbon.Among these Zn_(1-x)Co_(x)/NC electrocatalysts,Zn_(0.2)Co_(0.8)/NC shows the highest OER activity.The carbon nanowires appearing on the surface of Zn_(0.2)Co_(0.8)/NC nanoparticles are much more compared to that on others.The overpotential and Tafel slope of Zn_(0.2)Co_(0.8)/NC are 1.52 V and 98 eV dec-1,respectively.Zn_(0.2)Co_(0.8)/NC also exhibits outstanding long-term electrochemical durability.This finding can not only extend the application of MOFs,but can also present a new method for fabricating highly efficient OER electrocatalysts.展开更多
Correction for‘Influence of Zn and Co co-doping on oxygen evolution reaction electrocatalysis at MOF-derived N-doped carbon electrodes’by Xiaobing Yang et al.,Inorg.Chem.Front.,2019,DOI:10.1039/c9qi00334g.The author...Correction for‘Influence of Zn and Co co-doping on oxygen evolution reaction electrocatalysis at MOF-derived N-doped carbon electrodes’by Xiaobing Yang et al.,Inorg.Chem.Front.,2019,DOI:10.1039/c9qi00334g.The authors regret that an error is present within Fig.4.In Fig.4(b),we inadvertently re-used a figure that was published in our previous paper.1 The correct version of Fig.4 is shown below.展开更多
Mixed electronic and oxide ionic conduction was introduced in InGe_(2)O_(7)containing isolated Ge_(2)O_(7)units through the substitution of Zn^(2+)for In^(3+).The solid solution limit of Zn doping in In_(2−x)Zn_(x)Ge_...Mixed electronic and oxide ionic conduction was introduced in InGe_(2)O_(7)containing isolated Ge_(2)O_(7)units through the substitution of Zn^(2+)for In^(3+).The solid solution limit of Zn doping in In_(2−x)Zn_(x)Ge_(2)O_(7−0.5x)is 0–0.2,as confirmed by Rietveld refinements and systematic experiments.展开更多
The bimetallic nickel-cobalt phosphide (NiCoP) has been confirmed as an efficient electrocatalyst in water splitting. But little attention is paid to the selectivity and affinity of metal sites on hydrogen evolution r...The bimetallic nickel-cobalt phosphide (NiCoP) has been confirmed as an efficient electrocatalyst in water splitting. But little attention is paid to the selectivity and affinity of metal sites on hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Herein, we report a trace-Zn-doping (2.18 wt.%) NiCoP (Zn-NiCoP) whereby the nanoparticles self-aggregated to form elongated nanoneedles. We discover that both Co and Ni sites can be replaced by Zn. The Co substitution improves HER, while the Ni substitution dramatically reduces the energy barrier of the rate-determining step (*O → *OOH). The negative shift of d-band centers after Zn doping ameliorates the intermediate desorption. Therefore, Zn-NiCoP demonstrates superior electrocatalytic activity with overpotentials of 48 and 240 mV for HER and OER at 10 and 50 mA·cm^(−2), respectively. The cell voltage with Zn-NiCoP as both anode and cathode in water splitting was as low as 1.35 V at 10 mA·cm^(−2).展开更多
The main challenge of ZnO-based photodetectors is correlated with the diffculty of achieving both high photodetection performance and good environmental stability due to the deteriorated effect of photo corrosion unde...The main challenge of ZnO-based photodetectors is correlated with the diffculty of achieving both high photodetection performance and good environmental stability due to the deteriorated effect of photo corrosion under light illumination.Here,we presented the potential solution by applying Cu^(2+)-doped ZnS as protective coatings on ZnO nanorods based on solution synthesis,where the systematic investigations on such core/shell nanostructures were performed by conducting crystallographic,morphological,com positional,photoluminescent,and light-absorption characterizations.In addition,the designed Cu^(2+)-doped ZnS/ZnO-based photodetector demonstrated the substantial improvement of the specific detec tivities reaching 99.3×10^(12)and 127.2×10^(12)cm Hz^(1/2)W^(−1)under the light illuminations of 365 nm and 420 nm,which were more than 22 times and 45 times beyond those of bare ZnO,respectively.It should be noted that the improved environmental stability for long-term utilization was revealed,where the photoresponsivity was sustained to be above 95.4%for lasting 60 days.Significantly,the present study provided a facile approach to advance the development of high-performance,broadband and reliable photodetector designs.展开更多
Transition metal sulfides have been emerging as one of the most attractive and prospective catalysts for the direct conversion of solar energy into chemical fuels.Their intriguing compositional and electronic characte...Transition metal sulfides have been emerging as one of the most attractive and prospective catalysts for the direct conversion of solar energy into chemical fuels.Their intriguing compositional and electronic characteristics and their feasibility for integration in porous architectures endow metal sulfide materials with superior activity for photochemical catalysis.In the present work,high-surface-area Cu-doped ZnS nanocrystal(NC)-linked mesoporous frameworks are successfully synthesized for use as cost-effective catalysts for photochemical hydrogen evolution.Benefiting from the suitable band-edge alignment and enhanced visible light absorption resulting from the interfacial charge transfer between ZnS and Cu_(2)S NCs,there is a spatial separation of charge carriers which leads to excellent activity for photocatalytic hydrogen production.Moreover,the results obtained here show that surface defect passivation through a wet-chemical sulfidation process effectively increases the photochemical performance of the composite catalysts by improving the transport efficiency of electrons at the Cu_(2)S/ZnS interface and changing the Helmholtz layer potential drop at the ZnS/Cu_(2)S/electrolyte junction.Thus,a remarkable improvement of 1 mmol h^(−1)g_(cat)^(−1)for hydrogen evolution is observed with the sulfide-treated Cu_(2)S/ZnS catalyst containing 5 mol%Cu,which is associated with a 17.6%apparent quantum yield under 410 nm irradiation.This work provides an interesting strategy for enhancing the interface charge transfer properties and hydrogen evolution activity of metal sulfides by surface defect engineering with sulfide ions.展开更多
基金supported by the National Key Research and Development Program of China (Grant No.2024YFA1210400)the National Science Fund for Distinguished Young Scholars (Grant No.52525101)+3 种基金the National Natural Science Foundation of China (Grant Nos.52450001 and 22409014)the International Cooperation and Exchange of the National Natural Science Foundation of China (Grant No.52411540237)the Tencent Xplorer Prizethe support of the National High-Level Talent Special Support Programs—Young Talents。
文摘The interdependence of electrical parameters has long inhibited the progress of bismuth telluride(Bi_(2)Te3),limiting its widespread application in thermoelectric cooling and power generation.This work investigates the n-type Bi_(2)Te_(2.79)Se_(0.21)I_(0.004)(Bi_(2)(Te,Se)_(3),BTS)system with light Zn doping,revealing that Zn addition simultaneously enhances the Seebeck coefficient(S)and electrical conductivity(σ)through the modulation of defect composition and multi-level band regulation.The substitution of Zn atoms at Bi sites enhances S via bandgap(E_(g))widening,band flattening,and band splitting effects,contributing to a competitive power factor(PF)of∼60μW⋅cm^(−1)⋅K^(−2).Additionally,thermal conductivity is maintained at a low level,leading to an extraordinary figure-of-merit(ZT)value of∼1.3 at room temperature.Furthermore,the Bi_(2)Zn_(0.01)Te_(2.79)Se_(0.21)I_(0.004) system demonstrates impressive thermoelectric device performance,with a maximum cooling temperature difference(ΔT_(max))of∼70.0 K at 300 K,rising to∼78.0 K at 323 K and∼85.7 K at 343 K,as well as a maximum conversion efficiency(η_(max))of∼6.2%under aΔT of 200 K.This study clarifies the mechanism of Zn doping and presents a cost-effective strategy for enhancing the performance of n-type BTS thermoelectrics and their devices.
基金supported by the Beijing Natural Science Foundation(No.2232053)the National Natural Science Foundation of China(No.52002029)+1 种基金Natural Science Foundation of Guangdong Province(No.2022A1515011918)Research and Development Project of Henan Academy of Sciences China(No.20250618006).
文摘Efficient photocatalytic CO_(2)reduction to valuable fuels is an ideal strategy for addressing the energy and environmental crisis.Herein,we developed the Zn-incorporated hollow nanocages,assembled by NiCo-layered double hydroxide ultrathin nanosheets(NiCoZnx-LDH),as highly efficient photocatalysts.Spectroscopic characterization and theoretical calculations demonstrate that Zn doping leads to an upshift of the d-band center of Ni-Co dual sites,increasing unoccupied antibonding orbitals and enhancing the binding strength of adsorbates.Therefore,NiCoZn_(0.10)-LDH with the upgrade of d-band shows a lower·CO_(2)-formation energy,resulting in a more effective stabilization of the rate-limiting·CO_(2)-intermediate.This boosts the overall CO_(2)photoreduction performance over NiCoZn_(0.10)-LDH,resulting in a high CO yield of 158.1μmol·g^(-1)·h^(-1)with 92.1%selectivity.Our findings enrich the fundamental understanding of the CO_(2)activation mechanism and provide additional insights into the d-band center theory to enhance the photocatalytic activity for overall CO_(2)reduction.
基金supported by the National Natural Science Foundation of China(Grant No.51372064)the Natural Science Foundation of Hebei Province,China(Grant Nos.A2014201176 and E2017201209)+1 种基金the Outstanding Doctoral Cultivation Project of Hebei University(Grant No.YB201502)the Hebei Province Universities Science and Technology Program funded by the Hebei Provincial Education Department,China(Grant Nos.ZD2014018 and QN2017017)
文摘The thermoelectric performance of CdO ceramics was enhanced by simultaneously optimizing the electrical and thermal transport properties via a small amount of Zn doping （≤3%）. The introduction of Zn can obviously increase the electrical conductivity of CdO due to the simultaneous increase of carrier concentration and mobility, and eventually results in an improvement in power factor. Zn doping is also effective in suppressing the thermal conductivity of CdO because of stronger phonon scatterings from point defects, Zn-riched second phase, and grain boundaries. A best ZT of about 0.45 has been achieved in the Cd1-xZnxO systems at about 1000 K, which is comparable to the highest values reported for other n-type oxide TE materials.
文摘To optimize the electronic structure of photocatalyst,a facile one‐step approach is developed for the simultaneous realization of Zn‐doping and surface oxygen vacancies(SOVs)formation on SnO_(2).The Zn‐doped SnO_(2)with abundant SOVs exhibits efficient and stable performance for photocatalytic degradation of toluene under both low and high relative humidity.Experimental and theoretical calculations results show that the synergistic effects of Zn‐doping and SOVs on SnO_(2)can considerably boost the charge transfer and separation efficiency.Utilizing the in situ DRIFTS and theoretical calculations methods,it is revealed that the benzene ring of toluene is opened at benzoic acid on the SnO_(2)surface and selectively at benzaldehyde on the Zn‐doped SnO_(2)surface.This implies that Zn‐doped SnO_(2)photocatalysts shorten the pathway of toluene degradation,and toxic intermediates can be significantly inhibited.This work could provide a promising and sustainable route for safe and efficient removal of aromatic VOCs with photocatalytic technology.
基金supported by the Fundamental Research Funds for the Central Universities of China (No.JD2019JGPY0020)the National Natural Science Foundation of China (No.51573036)the Industry-University-Research Cooperation Project of Aviation Industry Corporation of China (No.CXY2013HFGD20)。
文摘The poor film formation of Cd Se/Zn S quantum dots(QDs) during spin-coating makes a substantial impact on the device performance of quantum dot light-emitting diodes(QLEDs). This work proposes a method to improve the morphology of the quantum dot light-emitting layer(EML) by adding small organic molecular 4,4'-Bis(9 H-carbazol-9-yl) biphenyl(CBP) into the layer. Its surface roughness reduces from 6.21 nm to 2.71 nm, which guarantees a good contact between hole transport layer(HTL) and EML. Consequently, the Cd Se/Zn S QDs:CBP based QLED achieves maximum external quantum efficiency(EQE) of 5.86%, and maximum brightness of 10 363 cd/m^(2). It is demonstrated that the additive of small organic molecules could be an effective way to improve the brightness and the efficiency of QLEDs.
文摘Low cost co-precipitation method was used to synthesize Cu(0-0.05)doped MgO samples with fixed concertation of Zn=0.01.X-ray diffraction(XRD)spectra confirmed the phase purity of the samples for 0≤Cu≤0.03 doping concentration.The secondary phase for 0.04≤Cu≤0.05 exhibited the formation of mixed metal oxides.The crystallite size was found to increase from 17.5 to 23.5 nm for 0≤Cu≤0.03 and then decreased from 22 to 18.5 nm for 0.04≤Cu≤0.05.The estimated bandgap first reduced from 5.48 to 4.88 eV and then increased from 5.21 to 5.36 eV.The morphology of the samples transformed from spheroidal shape to star-like shape.The obtained results reveal that the structural and optical property are in good agreement with the morphological transition.The peak shifting towards the lower values of vibrational frequency from 694 to 579 cm^(-1) confirms the incorporation of Cu/Zn in Mg-O lattice.The tuning of optical bandgap and structural properties with varying dopant concentration in MgO nanomaterials can be used for multifunctional modern energy storage and optoelectronic devices.
基金financially supported by the National Natural Science Foundation of China(No.51574071)
文摘Zn(Ⅱ)-doped graphitic carbon nitride(g-C3N4)with high photodegradation activity was prepared by one facile step.The morphology and structure of the prepared Zn(Ⅱ)-doped g-C3N4 were investigated,and the results showed that Zn(Ⅱ)could self-disperse during the pyrolysis process and Zn–N bond was formed between g-C3N4 and Zn.The dope of Zn(Ⅱ)influenced the structure of g-C3N4.The performance of photocatalytic activity of Zn(Ⅱ)-doped g-C3 N4 series indicated that the doped g-C3N4 with a small quantity of Zn(0.10 wt%)exhibits the best photocatalytic performance.The photodegradation activity for methyl orange was 2 times higher than that of pure g-C3N4.However,the photocatalytic activity decreased with the further increased content of Zn,which may be attributed to the structure change of g-C3N4 and the interaction of Zn–N bond between Zn and g-C3N4.Moreover,Zn(Ⅱ)-doped g-C3N4 showed good recycling photocatalytic stability.
文摘In the present work,a solution-based co-precipitation method has been adopted to synthesize pure and cobalt-doped ZnS quantum dots and characterized by XRD,SEM,TEM with EDX,FTIR and gas sensing properties.XRD analysis has shown a single phase of ZnS quantum dots having a zinc blend structure.TEM and XRD line broadening indicated that the average crystallite size in the sample is in the range of 2 to 5 nm.SEM micrographs show spherical-shaped quantum dots.FTIR studies show that cobalt has been successfully doped into the ZnS cubic lattice.EDX spectra have analyzed the elemental presence in the samples and it is evident that the spectra confirmed the presence of cobalt(Co),zinc(Zn),oxygen(O),and sulphur(S)elements only and no other impurities are observed.The ZnS-based quantum dot sensors reveal high sensitivity towards 50 ppm of ammonia vapors at an operating temperature of 70℃.Hence,ZnS-based quantum dots can be a promising and quick traceable sensor towards ammonia sensing applications with good response and recovery time.
基金Project supported by the National Natural Science Foundation of China(61465006,61265007)
文摘Effect of divalent dopants, Zn2＋ ion, on the high-order photon avalanche （PA） upconversion （UC） emission of Er3＋ doped BiOCl microcrystals was investigated. XRD results indicated that Zn2＋ ion dopants would mostly enter into the lattice space at low and moderate doping concentration, and began to substitute Bi3＋ ion gradually at heavily doping level. Under exaction at 980 nm, the PA UC of violet, green and red emission of Er3＋ ions could be observed, and the UC emission intensity increased with increasing the Zn2＋ addition below 8 mol.%, then decreased with further addition. Power dependence study showed that the dopant concentration of Zn2＋ had no obviously negative effect on the occurrence of PA emission. On the bases of results investigated herein, we considered that the lattice distortion by Zn2＋ doping could not directly change the special PA emission of BiOCI：Er3＋, but would improve the emission intensity when used as lattice modifier.
基金Project(BK2008591) supported by the Natural Science Foundation of Jiangsu Province,ChinaProject(2009RFQXG065) supported by Harbin Special Foundation of Technological Innovation Talent,China
文摘Nano-scale Ni（OH）2 doped with Zn was prepared by precipitation transformation method and characterized by XRD and TEM. The electrochemical performance was investigated by cyclic voltammetry （CV） and constant current technology. The measurement results indicate that the lattice parameters of nano-scale Ni（OH）2 are changed and the agglomeration of particles becomes obvious with the increased Zn-doped content. Compared with un-doped one, the discharge specific capacities ofnano-scale Ni（OH）2 doped with 10% Zn are enhanced by 8% and 6%, respectively, at the discharge rate of 0.2C and 3C. After 110 cycles, the discharge specific capacity of the sample doped with 10% zinc is still above 85% of its initial capacity discharged at 0.2C. Therefore, a suitable Zn-doped content is beneficial to improving the discharge performance of nano-scale Ni（OH）2.
基金Shanghai Committee of Science and Technology(11ZR1411400,10JC1404600)National Natural Science Foundation of China(61106064,60990312,61076060)
文摘CuInSe_(2)and Cu_(0.9)In_(0.9)Zn_(0.2)Se_(2)(CIZS)thin films were deposited by Radio-Frequency(RF)magnetron sputtering process.X-ray diffraction(XRD)results indicate CIZS film deposited at 300℃(CIZS-300)is(220)pre-ferred orientation which is different from(112)preferred orientation of other films.Cu-poor and appropriate tempera-ture are major factors for(220)preferred orientation of grains.The Raman spectra show a strong peak around 171 cm1 and a weak peak around 206 cm1,which corresponding to A1 and B2 modes.Substitution of Zn for Cu leads to a broadening and blue-shift of A1 Raman mode.The band gap Eopt of CIZS film increases due to a reduced Se p-Cu d interband repulsion with Zn doping.Scanning electron microscope(SEM)measurement demonstrates that the surface morphology of CIZS is more compact and smoother than that of CIS thin films.
基金supported by the National Natural Science Foundation of China(No.52306248)Natural Science Foundations of Hunan Province of China(Nos.2024JJ6387 and 2024JJ6370)+1 种基金Scientific Research Foundation of the University of South China(Nos.230XQD020 and 230XQD021)Natural Science Foundation of Chongqing of China(No.CSTB2023NSCQ-MSX0926).
文摘Zn is a frequently used and sometimes even an inevitably involved element (when zeolitic imidazolate framework-8 (ZIF-8) is adopted as the precursor) for preparing high-performance Fe-N-C oxygen reduction reaction (ORR) catalysts. However, how the Zn element affects the physicochemical architecture of the catalysts, how it enhances the catalytic activity and whether Zn atoms serve as the active centers remain unclear. Herein, we proposed a novel route that adopted pyrrole as the precursor and flexibly controlled the addition of exogenous Zn and Fe dopants before pyrrole polymerization. In this way, a series of nitrogen-carbon catalysts with or without Zn or Fe doping were synthesized. The detailed characterization revealed the role of Zn and Fe doping in the catalyst morphology, pore structure, active site configurations, ORR catalytic activity and fuel cell performance. Importantly, the findings revealed that Zn doping has little effect on the ORR mechanism and pathway. It enhances ORR activity primarily by increasing the number of active sites via introducing more micro- and meso-pores, rather than by creating new active sites. While Fe doping participated in forming both pores and active site centers. Moreover, the catalyst that co-doped with Zn and Fe atoms (Zn-FeNC), synthesized via this simple and template-free route we proposed, presented a unique hollow and hierarchical pore structure with highly boosted ORR activity. It exhibited a 40 mV higher E 1/2 value than Pt/C in alkaline media, along with a rapid current response in air-cathode of the direct formate fuel cell. These results are valuable in guiding the synthesis of high-performance Fe-N-C catalysts.
文摘Un-doped and Cu-doped ZnS（ZnS：Cu） thin films were synthesized by Successive Ion Layer Absorption and Reaction（SILAR） method. The UV–visible absorption studies have been used to calculate the band gap values of the fabricated ZnS：Cu thin films. It was observed that by increasing the concentration of Cu^2＋ ions, the Fermi level moves toward the edge of the valence band of ZnS. Photoluminescence spectra of un-doped and Cu-doped ZnS thin films was recorded under 355 nm. The emission spectrum of samples has a blue emission band at 436 nm.The peak positions of the luminescence showed a red shift as the Cu^2＋ C ion concentration was increased, which indicates that the acceptor level（of Cu^2＋） is getting close to the valence band of ZnS.
基金the Fujian Key Laboratory of Advanced Materials,Educational Research Projects for Young and Middle-aged Teachers in Fujian Province(JT180549)the Natural Science Foundation of Fujian Province(2019J01020797)+1 种基金The Project of Fujian Provincial Key Laboratory of Eco-Inductrial Green Technology(WYKF2018-8)the Program for Outstanding Young Scientific Research Talents in Fujian Province University(MinKeJiao,2018,No 47).
文摘Electrochemical conversion of water into oxygen and hydrogen gas is a highly efficient method to meet the energy requirement on a global scale and solve the global warming problem arising from the mass consumption of fossil sources.Therefore,it is important to develop a catalyst with excellent oxygen reduction reaction(OER)activity.In this paper,we adopted the cocrystallization technology to synthesize Zn_(1-x)Co_(x)-ZIF composites.Then,the Zn_(1-x)Co_(x)-ZIF composites were used as precursors to prepare the Zn_(1-x)Co_(x)/NC electrocatalyst(NC is N-doped carbon).The influence of the Zn element on the Zn_(1-x)Co_(x)/NC electrocatalyst for the oxygen reduction reaction has been explored.All as-prepared samples were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),and X-ray photoelectron spectroscopy(XPS).The results show that Zn_(1-x)Co_(x)/NC electrocatalysts exhibit excellent OER activity.And the doping of Zn has a great influence on the structure and OER efficiency of the Zn_(1-x)Co_(x)/NC electrocatalyst.After the pyrolysis process,the organic ligands of Zn_(1-x)Co_(x)-ZIF are transformed into porous carbon and Zn and Co nanoparticles are formed inside the carbon.Among these Zn_(1-x)Co_(x)/NC electrocatalysts,Zn_(0.2)Co_(0.8)/NC shows the highest OER activity.The carbon nanowires appearing on the surface of Zn_(0.2)Co_(0.8)/NC nanoparticles are much more compared to that on others.The overpotential and Tafel slope of Zn_(0.2)Co_(0.8)/NC are 1.52 V and 98 eV dec-1,respectively.Zn_(0.2)Co_(0.8)/NC also exhibits outstanding long-term electrochemical durability.This finding can not only extend the application of MOFs,but can also present a new method for fabricating highly efficient OER electrocatalysts.
文摘Correction for‘Influence of Zn and Co co-doping on oxygen evolution reaction electrocatalysis at MOF-derived N-doped carbon electrodes’by Xiaobing Yang et al.,Inorg.Chem.Front.,2019,DOI:10.1039/c9qi00334g.The authors regret that an error is present within Fig.4.In Fig.4(b),we inadvertently re-used a figure that was published in our previous paper.1 The correct version of Fig.4 is shown below.
基金National Natural Science Foundation of China(grant number 22090043)Guangxi Natural Science Foundation(grant number 2019GXNSFGA245006)for the financial support+4 种基金J.S.thanks National Natural Science Foundation of China(grant number 21527803,21621061)Ministry of Science and Technology of China(grant number 2016YFA0301004)for the financial supportJ.X.Thanks National Natural Science Foundation of China(grant number 21965008)Guangxi Natural Science Foundation(grant number 2021GXNSFFA220002)for the financial supportX.L.acknowledges funding from China Postdoctoral Science Foundation(grant number 8206300392).
文摘Mixed electronic and oxide ionic conduction was introduced in InGe_(2)O_(7)containing isolated Ge_(2)O_(7)units through the substitution of Zn^(2+)for In^(3+).The solid solution limit of Zn doping in In_(2−x)Zn_(x)Ge_(2)O_(7−0.5x)is 0–0.2,as confirmed by Rietveld refinements and systematic experiments.
基金supported by the National Natural Science Foundation of China(Nos.22179077 and 22479091)Shanghai Science and Technology Commission’s “2020 Science and Technology Innovation Action Plan”(No.20511104003)+4 种基金Natural Science Foundation in Shanghai(No.21ZR1424200)the National Natural Science Foundation of China(No.52334009)the Science and Technology Commission of Shanghai Municipality(No.21DZ1208900)Project of ShangHai Gas Turbine Union Innovation Center(No.GYQ1-2023-1-06)Postdoctoral Fellowship Program of CPSF(No.GZC20231536).
文摘The bimetallic nickel-cobalt phosphide (NiCoP) has been confirmed as an efficient electrocatalyst in water splitting. But little attention is paid to the selectivity and affinity of metal sites on hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Herein, we report a trace-Zn-doping (2.18 wt.%) NiCoP (Zn-NiCoP) whereby the nanoparticles self-aggregated to form elongated nanoneedles. We discover that both Co and Ni sites can be replaced by Zn. The Co substitution improves HER, while the Ni substitution dramatically reduces the energy barrier of the rate-determining step (*O → *OOH). The negative shift of d-band centers after Zn doping ameliorates the intermediate desorption. Therefore, Zn-NiCoP demonstrates superior electrocatalytic activity with overpotentials of 48 and 240 mV for HER and OER at 10 and 50 mA·cm^(−2), respectively. The cell voltage with Zn-NiCoP as both anode and cathode in water splitting was as low as 1.35 V at 10 mA·cm^(−2).
文摘The main challenge of ZnO-based photodetectors is correlated with the diffculty of achieving both high photodetection performance and good environmental stability due to the deteriorated effect of photo corrosion under light illumination.Here,we presented the potential solution by applying Cu^(2+)-doped ZnS as protective coatings on ZnO nanorods based on solution synthesis,where the systematic investigations on such core/shell nanostructures were performed by conducting crystallographic,morphological,com positional,photoluminescent,and light-absorption characterizations.In addition,the designed Cu^(2+)-doped ZnS/ZnO-based photodetector demonstrated the substantial improvement of the specific detec tivities reaching 99.3×10^(12)and 127.2×10^(12)cm Hz^(1/2)W^(−1)under the light illuminations of 365 nm and 420 nm,which were more than 22 times and 45 times beyond those of bare ZnO,respectively.It should be noted that the improved environmental stability for long-term utilization was revealed,where the photoresponsivity was sustained to be above 95.4%for lasting 60 days.Significantly,the present study provided a facile approach to advance the development of high-performance,broadband and reliable photodetector designs.
基金supported by the Hellenic Foundation for Research and Innovation(H.F.R.L.)under the“First Call for H.F.R.I.Research Projects to support Faculty members and Researchers and the procurement of high-cost research equipment grant”(Project Number:400)the Special Account for Research Funds of University of Crete(SARF UoC)(KA 10138).
文摘Transition metal sulfides have been emerging as one of the most attractive and prospective catalysts for the direct conversion of solar energy into chemical fuels.Their intriguing compositional and electronic characteristics and their feasibility for integration in porous architectures endow metal sulfide materials with superior activity for photochemical catalysis.In the present work,high-surface-area Cu-doped ZnS nanocrystal(NC)-linked mesoporous frameworks are successfully synthesized for use as cost-effective catalysts for photochemical hydrogen evolution.Benefiting from the suitable band-edge alignment and enhanced visible light absorption resulting from the interfacial charge transfer between ZnS and Cu_(2)S NCs,there is a spatial separation of charge carriers which leads to excellent activity for photocatalytic hydrogen production.Moreover,the results obtained here show that surface defect passivation through a wet-chemical sulfidation process effectively increases the photochemical performance of the composite catalysts by improving the transport efficiency of electrons at the Cu_(2)S/ZnS interface and changing the Helmholtz layer potential drop at the ZnS/Cu_(2)S/electrolyte junction.Thus,a remarkable improvement of 1 mmol h^(−1)g_(cat)^(−1)for hydrogen evolution is observed with the sulfide-treated Cu_(2)S/ZnS catalyst containing 5 mol%Cu,which is associated with a 17.6%apparent quantum yield under 410 nm irradiation.This work provides an interesting strategy for enhancing the interface charge transfer properties and hydrogen evolution activity of metal sulfides by surface defect engineering with sulfide ions.
