Ce–Zr solid solution(CexZr1-xO2,CZO)was prepared by the citric acid sol–gel method.The CZO was then used as a support for Pd/CZO catalysts for the oxidative carbonylation of phenol to diphenyl carbonate.The Pd/CZO c...Ce–Zr solid solution(CexZr1-xO2,CZO)was prepared by the citric acid sol–gel method.The CZO was then used as a support for Pd/CZO catalysts for the oxidative carbonylation of phenol to diphenyl carbonate.The Pd/CZO catalyst showed enhanced activity and diphenyl carbonate selectivity compared with the Pd/CeO2 catalyst.The catalytic performance of Pd/CZO was influenced by the calcination temperature of the CZO support.X-ray diffraction,scanning electron microscopy,N2 adsorption–desorption measurements,X-ray photoelectron spectroscopy and H2 temperature-programmed reduction measurements were used to investigate the effects of Zr doping and calcination temperature.The catalytic performance of Pd/CZO and Pd/CeO2 for the oxidative carbonylation of phenol was affected by several factors,including the specific surface area,Ce^3+and/or oxygen vacancy content,oxygen species type and Pd(II)content of the catalyst.All these properties were influenced by Zr doping and the calcination temperature of the CZO support.展开更多
There has been a continuous effort to improve the thermal stability of subnanometric platinum(Pt)cluster(<2 nm) catalyst because Pt cluster on CeO_(2) support can be mobile and aggregated into nanoparticle on heati...There has been a continuous effort to improve the thermal stability of subnanometric platinum(Pt)cluster(<2 nm) catalyst because Pt cluster on CeO_(2) support can be mobile and aggregated into nanoparticle on heating at elevated temperatures,yet this great challenge remains.In this study,a strategy is reported to improve the thermal stability of subnanometric Pt cluster by hydrothermal deposition method.Based on this method,zirconium(Zr) was precisely doped on surface of Ce_(0.95)Zr_(0.05)O_(2) by accurately controlling Pt subnanometric cluster size.The surface doping of Zr is favorable for forming the Zr-O-Ce site and activating surface lattice oxygen atoms,which results in strong electronic interactions to stabilize the Pt subnanometric cluster.After high-temperature aging treatment at 1000℃/4 h,the single atom Pt supported on CeO_(2) is aggregated into larger sized(>3 nm) nanoparticle.In contrast,the single atom Pt supported on Ce_(0.95)Zr_(0.0)5O_(2) displays less agglomeration into subnanometric cluster with size of(1.4±0.3) nm.Moreover,the CO oxide catalytic performance of Ce_(0.95)Zr_(0.0)5O_(2)-Pt is 26% and 31%higher than that of CeO_(2)-Pt and commercial Al_(2)O_(3)-Pt catalysts,respectively.The experimental and density functional theory(DFT) calculations indicate that the Zr-O-Ce site and Pt subnanometric cluster interface have more defect sites and active oxygen species than CeO_(2)-Pt interface,which activate the Mars van Krevelen(MvK) mechanism,facilitating the catalytic performance.展开更多
Zr4＋ doped Bi2WO6 was prepared by a fast microwave-assisted hydrothermal method and used for photocatalytic degradation of organic dyes. The as-prepared samples were characterized by X-ray diffraction（XRD）, transmi...Zr4＋ doped Bi2WO6 was prepared by a fast microwave-assisted hydrothermal method and used for photocatalytic degradation of organic dyes. The as-prepared samples were characterized by X-ray diffraction（XRD）, transmission electron microscopy（TEM） and UV-Vis spectroscopy. The results indicate that cell volume of Bi2WO6 has a slight increase dependent on the substitution of W6＋ by Zr4＋ with increasing the Zr doping amount. The photocatalytic performance of Zr4＋ doped Bi2WO6 was evaluated by the photodegradation of MO under visible light irradiation. Compared with samples obtained with traditional hydrothermal method as well as pure Bi2WO6, an obviously improved photocatalytic efficiency of Zr4＋ doped Bi2WO6 is achieved by this microwave-assisted hydrothermal way. The 3% Zr doped Bi2WO6 sample exhibited the best photocatalytic activity, which is probably because of the appropriate proportion of components and optimum amount of oxygen vacancies of the sample.展开更多
Sulfide-based all-solid-state lithium batteries(ASSLBs) with nickel-rich oxide cathodes are emerging as primary contenders for the next generation rechargeable batteries,owing to their superior safety and energy densi...Sulfide-based all-solid-state lithium batteries(ASSLBs) with nickel-rich oxide cathodes are emerging as primary contenders for the next generation rechargeable batteries,owing to their superior safety and energy density.However,the all-solid-state batteries with nickel-rich oxide cathodes suffer from performance degradation due to the reactions between the highly reactive surface oxygen of the cathode and the electrolyte,as well as the instability of the bulk oxygen structure in the cathode.Herein,we propose a synergistic modification design scheme to adjust the oxygen activity from surface to bulk.The LiBO_(2)coating inhibits the reactivity of surface lattice oxygen ions.Meanwhile,Zr doping in the bulk phase forms strong Zr-O covalent bonds that stabilize the bulk lattice oxygen structure.The synergistic effect of these modifications prevents the release of oxygen,thus avoiding the degradation of the cathode/SE interface.Additionally,the regulation of surface-to-bulk oxygen activity establishes a highly stable interface,thereby enhancing the lithium ion diffusion kinetics and mechanical stability of the cathode.Consequently,cathodes modified with this synergistic strategy exhibit outstanding performance in sulfide-based ASSLBs,including an ultra-long cycle life of 100,000 cycles,ultra-high rate capability at 45C,and 85% high active material content in the composite cathode.Additionally,ASSLB exhibits stable cycling under high loading conditions of 82.82 mg cm^(-2),achieving an areal capacity of 17.90 mA h cm^(-2).These encouraging results pave the way for practical applications of ASSLBs in fast charging,long cycle life,and high energy density in the future.展开更多
Ni-rich cathodes exhibit appealing properties,such as high capacity density,low cost,and prominent energy density.However,the inferior ionic conductivity and bulk structural degradation become bottlenecks for Ni-rich ...Ni-rich cathodes exhibit appealing properties,such as high capacity density,low cost,and prominent energy density.However,the inferior ionic conductivity and bulk structural degradation become bottlenecks for Ni-rich cathodes and severely limit their commercial utilization.Traditional coating and doping methods suffer fatal drawbacks in functioning as a unit and cannot radically promote material performance to meet the needs of Li-ion batteries(LIBs).Herein,we successfully devised an ingenious and facile synthetic method to establish Ni-rich oxides with a La_(2)Zr_(2)O_(7) coating and Zr doping.The coating layer improves the ion diffusion kinetics and enhances Li-ion transportation while Zr doping effectively suppresses the phase transition of LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) cathode.Owing to the synergetic effect of Zr doping and La_(2)Zr_(2)O_(7) coating,the modified material shows prominent initial discharge capacity of 184.7 m Ah g^(-1) at 5℃ and maintains 177.5 m Ah g^(-1) after 100 cycles at 1℃.Overall,the proposed feasible electrode design method can have a far-reaching impact on further fabrication of advanced cathodes for high-performance LIBs.展开更多
Na-based layered transition metal oxides with O_(3)-type structure have been considered to be promising cathodes for Na-ion batteries. However, the intrinsically limited Na-ion conductivity induced by the Otype Na-coo...Na-based layered transition metal oxides with O_(3)-type structure have been considered to be promising cathodes for Na-ion batteries. However, the intrinsically limited Na-ion conductivity induced by the Otype Na-coordinate environment compromises their rate and cycle capability, hindering their practical application. Here, we report an interphase-structure tailoring strategy that improves the electrochemical properties of O_(3)-type layered cathodes achieved through surface coating and doping processes.Specifically, a Zr-doped interphase structure is designed in the model compound NaNi_(1/3)Mn_(1/3)Fe_(1/3)O_(2) using the ionic conductor Na_(3)Zr_(2)Si_(2)PO_(12) as the surface coating material and Zr-dopant provider. We discover that the modified NaNi_(1/3)Mn_(1/3)Fe_(1/3)O_(2)cathode shows a stable Na-storage structure as well as an enhanced rate/cycle capability. Combined with theoretical calculations, it is suggested that the superior electrochemical performances originate from the Zr-doped interphase structure, which has an enlarged Na layer spacing that forms favorable Na-ion diffusion channels. This work highlights a general material interface optimization method which opens a new perspective for fabricating high-performance electrodes for Na-ion batteries and beyond.展开更多
基金supported by the National Natural Science Foundation of China(21776057)the Natural Science Foundation of Tianjin City(Nos.17JCYBJC20100,18JCYBJC21500)the Fund Program for the Scientific Activities of Selected Returned Overseas Professionals in Hebei Province(CL201605)。
文摘Ce–Zr solid solution(CexZr1-xO2,CZO)was prepared by the citric acid sol–gel method.The CZO was then used as a support for Pd/CZO catalysts for the oxidative carbonylation of phenol to diphenyl carbonate.The Pd/CZO catalyst showed enhanced activity and diphenyl carbonate selectivity compared with the Pd/CeO2 catalyst.The catalytic performance of Pd/CZO was influenced by the calcination temperature of the CZO support.X-ray diffraction,scanning electron microscopy,N2 adsorption–desorption measurements,X-ray photoelectron spectroscopy and H2 temperature-programmed reduction measurements were used to investigate the effects of Zr doping and calcination temperature.The catalytic performance of Pd/CZO and Pd/CeO2 for the oxidative carbonylation of phenol was affected by several factors,including the specific surface area,Ce^3+and/or oxygen vacancy content,oxygen species type and Pd(II)content of the catalyst.All these properties were influenced by Zr doping and the calcination temperature of the CZO support.
基金supported by National Natural Science Foundation of China (52204376)Youth Foundation of Hebei Province (E2022103007)+1 种基金Open Project of Yunnan Precious Metals Laboratory Co.(YPML-20240502059)Young Elite Scientists Sponsorship Program by CAST (2021QNRC001)。
文摘There has been a continuous effort to improve the thermal stability of subnanometric platinum(Pt)cluster(<2 nm) catalyst because Pt cluster on CeO_(2) support can be mobile and aggregated into nanoparticle on heating at elevated temperatures,yet this great challenge remains.In this study,a strategy is reported to improve the thermal stability of subnanometric Pt cluster by hydrothermal deposition method.Based on this method,zirconium(Zr) was precisely doped on surface of Ce_(0.95)Zr_(0.05)O_(2) by accurately controlling Pt subnanometric cluster size.The surface doping of Zr is favorable for forming the Zr-O-Ce site and activating surface lattice oxygen atoms,which results in strong electronic interactions to stabilize the Pt subnanometric cluster.After high-temperature aging treatment at 1000℃/4 h,the single atom Pt supported on CeO_(2) is aggregated into larger sized(>3 nm) nanoparticle.In contrast,the single atom Pt supported on Ce_(0.95)Zr_(0.0)5O_(2) displays less agglomeration into subnanometric cluster with size of(1.4±0.3) nm.Moreover,the CO oxide catalytic performance of Ce_(0.95)Zr_(0.0)5O_(2)-Pt is 26% and 31%higher than that of CeO_(2)-Pt and commercial Al_(2)O_(3)-Pt catalysts,respectively.The experimental and density functional theory(DFT) calculations indicate that the Zr-O-Ce site and Pt subnanometric cluster interface have more defect sites and active oxygen species than CeO_(2)-Pt interface,which activate the Mars van Krevelen(MvK) mechanism,facilitating the catalytic performance.
基金supported by the China Postdoctoral Science Foundation(2014M550337)Natural Science Foundation of High Education School of Anhui Province(KJ2013A091)+1 种基金Science and Technology Project of Anhui Province(1604a0802122)Fund of Key Laboratory of Optoelectronic Materials Chemistry and Physics,Chinese Academy of Sciences
文摘Zr4＋ doped Bi2WO6 was prepared by a fast microwave-assisted hydrothermal method and used for photocatalytic degradation of organic dyes. The as-prepared samples were characterized by X-ray diffraction（XRD）, transmission electron microscopy（TEM） and UV-Vis spectroscopy. The results indicate that cell volume of Bi2WO6 has a slight increase dependent on the substitution of W6＋ by Zr4＋ with increasing the Zr doping amount. The photocatalytic performance of Zr4＋ doped Bi2WO6 was evaluated by the photodegradation of MO under visible light irradiation. Compared with samples obtained with traditional hydrothermal method as well as pure Bi2WO6, an obviously improved photocatalytic efficiency of Zr4＋ doped Bi2WO6 is achieved by this microwave-assisted hydrothermal way. The 3% Zr doped Bi2WO6 sample exhibited the best photocatalytic activity, which is probably because of the appropriate proportion of components and optimum amount of oxygen vacancies of the sample.
基金financially supported by the National Natural Science Foundation of China (52474338,22109084 and 52304338)the Hunan Provincial Key Research and Development Program (2024JK2093,2023GK2016)supported in part by the High Performance Computing Center of Central South University.
文摘Sulfide-based all-solid-state lithium batteries(ASSLBs) with nickel-rich oxide cathodes are emerging as primary contenders for the next generation rechargeable batteries,owing to their superior safety and energy density.However,the all-solid-state batteries with nickel-rich oxide cathodes suffer from performance degradation due to the reactions between the highly reactive surface oxygen of the cathode and the electrolyte,as well as the instability of the bulk oxygen structure in the cathode.Herein,we propose a synergistic modification design scheme to adjust the oxygen activity from surface to bulk.The LiBO_(2)coating inhibits the reactivity of surface lattice oxygen ions.Meanwhile,Zr doping in the bulk phase forms strong Zr-O covalent bonds that stabilize the bulk lattice oxygen structure.The synergistic effect of these modifications prevents the release of oxygen,thus avoiding the degradation of the cathode/SE interface.Additionally,the regulation of surface-to-bulk oxygen activity establishes a highly stable interface,thereby enhancing the lithium ion diffusion kinetics and mechanical stability of the cathode.Consequently,cathodes modified with this synergistic strategy exhibit outstanding performance in sulfide-based ASSLBs,including an ultra-long cycle life of 100,000 cycles,ultra-high rate capability at 45C,and 85% high active material content in the composite cathode.Additionally,ASSLB exhibits stable cycling under high loading conditions of 82.82 mg cm^(-2),achieving an areal capacity of 17.90 mA h cm^(-2).These encouraging results pave the way for practical applications of ASSLBs in fast charging,long cycle life,and high energy density in the future.
基金supported by the National Natural Science Foundation of China(Grant No.51974368)the Fundamental Research Funds for the Central Universities of Central South University(2019zzts251)。
文摘Ni-rich cathodes exhibit appealing properties,such as high capacity density,low cost,and prominent energy density.However,the inferior ionic conductivity and bulk structural degradation become bottlenecks for Ni-rich cathodes and severely limit their commercial utilization.Traditional coating and doping methods suffer fatal drawbacks in functioning as a unit and cannot radically promote material performance to meet the needs of Li-ion batteries(LIBs).Herein,we successfully devised an ingenious and facile synthetic method to establish Ni-rich oxides with a La_(2)Zr_(2)O_(7) coating and Zr doping.The coating layer improves the ion diffusion kinetics and enhances Li-ion transportation while Zr doping effectively suppresses the phase transition of LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) cathode.Owing to the synergetic effect of Zr doping and La_(2)Zr_(2)O_(7) coating,the modified material shows prominent initial discharge capacity of 184.7 m Ah g^(-1) at 5℃ and maintains 177.5 m Ah g^(-1) after 100 cycles at 1℃.Overall,the proposed feasible electrode design method can have a far-reaching impact on further fabrication of advanced cathodes for high-performance LIBs.
基金The University of Chinese Academy of Sciences,and the Scientific Instrument Developing Project of the Chinese Academy of Sciences (ZDKYYQ20170001):China the Guangdong Basic and Applied Basic Research Foundation (2019A1515111025) China the Japan Synchrotron Radiation Research Institute (2019B1096)Japan。
文摘Na-based layered transition metal oxides with O_(3)-type structure have been considered to be promising cathodes for Na-ion batteries. However, the intrinsically limited Na-ion conductivity induced by the Otype Na-coordinate environment compromises their rate and cycle capability, hindering their practical application. Here, we report an interphase-structure tailoring strategy that improves the electrochemical properties of O_(3)-type layered cathodes achieved through surface coating and doping processes.Specifically, a Zr-doped interphase structure is designed in the model compound NaNi_(1/3)Mn_(1/3)Fe_(1/3)O_(2) using the ionic conductor Na_(3)Zr_(2)Si_(2)PO_(12) as the surface coating material and Zr-dopant provider. We discover that the modified NaNi_(1/3)Mn_(1/3)Fe_(1/3)O_(2)cathode shows a stable Na-storage structure as well as an enhanced rate/cycle capability. Combined with theoretical calculations, it is suggested that the superior electrochemical performances originate from the Zr-doped interphase structure, which has an enlarged Na layer spacing that forms favorable Na-ion diffusion channels. This work highlights a general material interface optimization method which opens a new perspective for fabricating high-performance electrodes for Na-ion batteries and beyond.
