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| 1 | Direct Z-scheme WO_(3-x) nanowire-bridged TiO_(2) nanorod arrays for highly efficient photoelectrochemical overall water splitting显示文摘All-solid-state Z-scheme photocatalysts for overall water splitting to evolve H_(2) is a promising strategy for efficient conversion of solar energy.However,most of these strategies require redox mediators.Herein,a direct Z-scheme photoelectrocatalytic electrode based on a WO_(3-x)nanowire-bridged TiO_(2)nanorod array heterojunction is constructed for overall water splitting,producing H_(2).The as-prepared WO_(3-x)/TiO_(2)nanorod array heterojunction shows photoelectrochemical(PEC)overall water splitting activity evolving both H_(2) and O_(2)under UV-vis light irradiation.An optimum PEC activity was achieved over a 1.67-WO_(3-x)/TiO_(2)photoelectrode yielding maximum H_(2) and O_(2)evolution rates roughly 11 times higher than that of pure TiO_(2)nanorods without any sacrificial agent or redox mediator.The role of oxygen vacancy in WO_(3-x)in affecting the H_(2) production rate was also comprehensively studied.The superior PEC activity of the WO_(3-x)/TiO_(2)electrode for overall water splitting can be ascribed to an efficient Z-scheme charge transfer pathway between the WO_(3-x)nanowires and TiO_(2)nanorods,the presence of oxygen vacancies in WO_(3-x),and a bias potential applied on the photoelectrode,resulting in effective spatial charge separation.This study provides a novel strategy for developing highly efficient PECs for overall water splitting. | Sheng Lin He Ren Zhi Wu Lan Sun Xia-Guang Zhang Yu-Mei Lin Kelvin H.L.Zhang Chang-Jian Lin Zhong-Qun Tian Jian-Feng Li | 2021 | Journal of Energy Chemistry2021，30，8： | 2 |
| 2 | 查看详情显示文摘 | D.W.Zhu J.G.Bo H.L.Zhang | | 0，，： | 1 |
| 3 | Revealing the correlation between structure evolution and electrochemical performance of high-voltage lithium cobalt oxide显示文摘Lithium cobalt oxide(LCO)is the dominating cathode materials for lithium-ion batteries(LIBs)deployed in consumer electronic devices for its superior volumetric energy density and electrochemical performances.The constantly increasing demands of higher energy density urge to develop high-voltage LCO via a variety of strategies.However,the corresponding modification mechanism,especially the influence of the long-and short-range structural transitions at high-voltage on electrochemical performance,is still not well understood and needs further exploration.Based on ss-NMR,in-situ X-ray diffraction,and electrochemical performance results,it is revealed that the H3 to H1-3 phase transition dictates the structural reversibility and stability of LCO,thereby determining the electrochemical performance.The introduction of La and Al ions could postpone the appearance of H1-3 phase and induce various types of local environments to alleviate the volume variation at the atomic level,leading to better reversibility of the H1-3 phase and smaller lattice strain,and significantly improved cycle performance.Such a comprehensive long-range,local,and electronic structure characterization enables an in-depth understanding of the structural evolution of LCO,providing a guiding principle for developing high-voltage LCO for high energy density LIBs. | Jiajia Wan Jianping Zhu Yuxuan Xiang Guiming Zhong Xiangsi Liu Yixiao Li Kelvin H.L.Zhang Chaoyu Hong Jianming Zheng Kai Wang Yong Yang | 2021 | Journal of Energy Chemistry2021，30，3： | 1 |
| 4 | 查看详情显示文摘 | H.L.Zhang B.Johansson L.Vites | | 0，，22： | 1 |
| 5 | Correlating the electronic structure of perovskite La_(1-x)SrxCoO_(3) with activity for the oxygen evolution reaction:The critical role of Co 3d hole state显示文摘Perovskite LaCoO_(3) is being increasingly explored as an effective low-cost electrocatalyst for the oxygen evolution reaction(OER).Sr doping in LaCoO_(3)(La1-xSrxCoO_(3))has been found to substantially increase its catalytic activity.In this work,we report a detailed study on the evolution of the electronic structure of La1-xSrxCoO_(3) with 0≤x≤1 and its correlation with electrocatalytic activity for the OER.A combination of X-ray photoemission spectroscopy(XPS)and X-ray absorption spectroscopy(XAS)was used to unravel the electronic density of states(DOS)near the Fermi level(EF),which provide insights into the key electronic structure features for the enhanced OER catalytic activity.Detailed analysis on the Co L-edge XAS suggest that LaCoO_(3) has a low spin state with t_(2g)^(6) e_(g)^(0) configuration at room temperature.This implies that the high OER catalytic activity of LaCoO_(3) should not be rationalized by the occupancy of eg=1 descriptor.Substituting Sr^(2+) for La^(3+) in LaCoO_(3) induces Co4+oxidation states and effectively dopes hole states into the top of valence band.A semiconductor-to-metal transition is observed for x>0.2,due to the holeinduced electronic DOS at the EF and increased hybridization between Co 3 d and O 2 p.Such an electronic modulation enhances the surface adsorption of the*OH intermediate and reduces the energy barrier for interfacial charge transfer,thus improving the OER catalytic activity in La_(1-x)Sr_(x)CoO_(3).In addition,we found that the La_(1-x)Sr_(x)CoO_(3) surface undergoes amorphization after certain period of OER measurement,leading to a partial deactivation of the electrocatalyst.High Sr doping levels accelerated the amorphization process. | Zechao Shen Mei Qu Jueli Shi Freddy E.Oropeza Victor A.de la Peña O’Shea Giulio Gorni C.M.Tian Jan P.Hofmann Jun Cheng Jun Li Kelvin H.L.Zhang | 2022 | Journal of Energy Chemistry2022，31，2： | 1 |
| 6 | Solid solution strengthening of high-entropy alloys from first-principles study显示文摘Solid solution strengthening(SSS)is one kind of strengthening mechanisms and plays an important role in alloy design,in particular for single-phase alloys including high-entropy alloys(HEAs).The classical Labusch–Nabarro model and its expansions are most widely applicable to treating SSS of solid solution alloys including both conventional alloys(CAs)and HEAs.In this study,the SSS effects in a series of Febased CAs and HEAs are investigated by using the classical Labusch–Nabarro model and its expansions.The size misfit and shear modulus misfit parameters are derived from first-principles calculations.Based on available experimental data in combination with empirical SSS model,we propose fitting constants(i.e.,the ratio between experimental hardness and predicted SSS effect)for these two families of alloys.The predicted host/alloy family-dependent fitting constants can be used to estimate the hardness of these SSS alloys.General agreement between predicted and measured hardness values is satisfactory for both CAs and HEAs,implying that the proposed approach is reliable and successful. | H.L.Zhang D.D.Cai X.Sun H.Huang S.Lu Y.Z.Wang Q.M.Hu L.Vitos X.D.Ding | 2022 | Journal of Materials Science & Technology2022，，26： | 1 |
| 7 | Materials Research Advances towards High-Capacity Battery/Fuel Cell Devices(Invited paper)显示文摘The world has entered an era featured with fast transportations,instant communications,and prompt technological revolutions,the further advancement of which all relies fundamentally,yet,on the development of cost-effective energy resources allowing for durable and high-rate energy supply.Current battery and fuel cell systems are challenged by a few issues characterized either by insufficient energy capacity or by operation instability and,thus,are not ideal for such highly-demanded applications as electrical vehicles and portable electronic devices.In this mini-review,we present,from materials perspectives,a few selected important breakthroughs in energy resources employed in these applications.Prospectives are then given to look towards future research activities for seeking viable materials solutions for addressing the capacity,durability,and cost shortcomings associated with current battery/fuel cell devices. | wei-dong he lu-han ye ke-chun wen ya-chun liang wei-qiang lv gao-long zhu kelvin h.l.zhang | 2016 | Journal of Electronic Science and Technology2016，14，1： | 0 |
| 8 | Modulation of the electronic states of perovskite SrCrO3 thin films through protonation via low-energy hydrogen plasma implantation approaches显示文摘Hydrogenation of transition metal oxides offers a powerful platform to tailor physical functionalities as well as for potential applications in modern electronic technologies.An ideal nondestructive and efficient hydrogen incorporation approach is important for the realistic technological applications.We demonstrate the proton injection on SrCro3 thin films via an efficient low-energy hydrogen plasma implantation experiments,without destroying the original lattice framework.Hydrogen ions accumu-late largely at the interfacial regions with amorphous character which extend about one-third of the total thickness.The Hx.SrCro3(HSCO)thin films appear like exfoliated layers which however retain the fully strained state with distorted perovskite structure.Proton doping induces the change of Cr oxidation state from Cr^4+to Cr^3+in HSCO thin films and a transition from metallic to insulat-ing phase.Our investigations suggest an attractive platform in manipulating the electronic phases in proton-based approaches and may offer a potential peeling off strategy for nanoscale devices through low-energy hydrogen plasma implantation approaches. | Meng Wu Shanquan Chen Chuanwei Huang Xing Ye Haiping Zhou Xiaochun Huang Kelvin H.L.Zhang Wensheng Yan Lihua Zhang Kisslinger Kim Yingge Du Scott Chambers Jin-Cheng Zheng Hui-Qiong Wang | 2020 | Frontiers of physics2020，15，1： | 0 |
| 9 | Transparent conductive SnO_(2)thin films via resonant Ta doping显示文摘Transparent conductive oxide(TCO)thin films are highly desired as electrodes for modern flat-panel displays and solar cells.Alternative indium-free TCO materials are highly needed,because of the scarcity and the high price of indium.Based on the mechanism of resonant doping,Ta has been identified as an effective dopant for SnO_(2)to achieve highly conductive and transparent TCO.In this work,we fabricated a series of Ta-doped SnO_(2)thin films(Sn_(1-x)Ta_(x)O_(2),x=0.001,0.01,0.02,0.03)with high conductivity and high optical transparency via a low-cost sol-gel spin coating method.The Sn_(0.98)Ta_(0.02)O_(2)film achieves the highest electrical conductivity of 855 S cm-1with a carrier concentration of2.3×10^(20)cm^(-3)and high mobility of 23 cm^(2)V^(-1)s^(-1).The films exhibit a very high optical transparency of 89.5%in the visible light region.High-resolution X-ray photoemission spectroscopy and optical spectroscopy were combined to gain insights into the electronic structure of the Sn_(1-x)Ta_(x)O_(2)films.The optical bandgaps of the films are increased from 3.96 eV for the undoped SnO_(2)to 4.24 eV for the Sn_(0.98)Ta_(0.02)O_(2)film due to the occupation of the bottom of conduction band by free electrons,i.e.,the Burstein-Moss effect.Interestingly,a bandgap shrinkage is also directly observed due to the bandgap renormalization arising from many-body interactions.The double guarantee of transparency and conductivity in Sn_(1-x)Ta_(x)O_(2)films and the low-cost growth method provide a new platform for optoelectronic and solar cell applications. | Vedaste Uwihoreye Zhenni Yang Jia-Ye Zhang Yu-Mei Lin Xuan Liang Lu Yang Kelvin H.L.Zhang | 2023 | Science China Materials2023，66，1： | 0 |
| 10 | Enhanced mechanical performance of grain boundary precipitation-hardened high-entropy alloys via a phase transformation at grain boundaries显示文摘Grain-boundary(GB)precipitation has a significant adverse effect on plasticity of alloys,which easily leads to catastrophic intergranular failure in safety-critical applications under high external loading.Herein,we report a novel strategy that uses the local stress concentration induced by GB precipitates as a driving force to trigger phase transformation of preset non-equiatomic high-entropy solid-solution phase at GBs.This in situ deformation-induced phase transformation at GBs introduces a well-known effect:transformation-induced plasticity(TRIP),which enables an exceptional elongation to fracture(above 38%)at a high strength(above 1.5 GPa)in a GB precipitation-hardened high-entropy alloy(HEA).The present strategy in terms of'local stress concentration-induced phase transformations at GBs'may provide a fundamental approach by taking advantage of(rather than avoiding)the GB precipitation to gain a superior combination of high strength and high ductility in HEAs. | Y.L.Qi L.Zhao X.Sun H.X.Zong X.D.Ding F.Jiang H.L.Zhang Y.K.Wu L.He F.Liu S.B.Jin G.Sha J.Sun | 2021 | Journal of Materials Science & Technology2021，，27： | 0 |
| 11 | Adjusting oxygen vacancies in perovskite LaCoO_(3)by electrochemical activation to enhance the hydrogen evolution reaction activity in alkaline condition显示文摘Developing highly-active,earth-abundant non-precious-metal catalysts for hydrogen evolution reaction(HER)in alkaline solution would be beneficial to sustainable energy storage.Perovskite oxides are generally regarded as low-active HER catalysts,due to their inapposite hydrogen adsorption and water dissociation.Here,we report a detailed study on perovskite LaCoO_(3)epitaxial thin films as a model catalyst to significantly enhance the HER performance via an electrochemical activation process.As a result,the overpotential for the activation films to achieve a current density of 0.36 m A/cm^(2)is 238 m V,reduced by more than 200 m V in comparison with that of original samples.Structural characterization revealed the activation process dramatically increases the concentration of oxygen vacancies(Vo)on the surface of LaCoO_(3).We established the relationship between the electronic structure induced by Vo and the enhanced HER activity.Further theoretical calculations revealed that the Vo optimizes the hydrogen adsorption and dissociation of water on the surface of LaCoO_(3)thin films,thus improving the HER catalytic activity.This work may promote a deepened understanding of perovskite oxides for HER mechanism by Vo adjusting and a new avenue for designing highly active electrochemical catalysts in alkaline solution. | Chengrong Wu Yan Sun Xiaojian Wen Jia-Ye Zhang Liang Qiao Jun Cheng Kelvin H.L.Zhang | 2023 | Journal of Energy Chemistry2023，，1： | 0 |
| 12 | Vertically aligned Ni/NiO nanocomposites with abundant oxygen deficient hetero-interfaces for enhanced overall water splitting显示文摘The design of heterostructured transition metal-based electrocatalysts with controlled composition and interfaces is key to increasing the efficiency of the water electrolysis and the elucidation of reaction mechanisms.In this work,we report the synthesis of well-controlled vertically aligned Ni/NiO nanocomposites consisting of Ni nanoclusters embedded in NiO,which result in highly efficient electrocatalysts for overall water splitting.We show that such a high catalytic efficiency toward both the hydrogen evolution reaction(HER)and the oxygen evolution reaction(OER)originates from a synergetic effect at Ni/NiO interfaces that significantly reduces the energy barrier for water dissociation,and favours the formation of reactive H*intermediates on the Ni side of the interface,and OH_(ads) on the NiO side of the interface.A study of water chemisorption based on near-ambient pressure photoelectron spectroscopy indicates that the abundant hetero-interfaces in Ni/NiO nanocomposite promote the dissociation of water with a three-fold increase in the surface concentration of OH_(ads) compared with pure NiO.Density functional theory calculations indicate that Ni/NiO interface leads to the reduction of the water dissociation energy barrier due to a high concentration of oxygen vacancies at NiO side of the interface,whereas the formation of highly active metallic Ni sites with an optimal value of Gibbs free energy of H*(ΔG_(H*)=−0.16 eV)owes to a favourable adjustment of the electron energetics at the interface,thus accelerating the overall electrochemical water splitting. | Hongxia Wang Meiyan Cui Gaoliang Fu Jiaye Zhang Xingyu Ding Irene Azaceta Matthew Bugnet Demie M.Kepaptsoglou Vlado K.Lazarov Victor Ade la Peña O’Shea Freddy E.Oropeza Kelvin H.L.Zhang | 2022 | Science China Chemistry2022，65，10： | 0 |
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