In the pursuit of stable,high performance Ni-based oxygen evolution reaction(OER)electrocatalysts,modifying the local chemical compositions or fabricating hybrid nanostructures to generate abundant interfaces for impr...In the pursuit of stable,high performance Ni-based oxygen evolution reaction(OER)electrocatalysts,modifying the local chemical compositions or fabricating hybrid nanostructures to generate abundant interfaces for improving the water oxidation activity of electrocatalysts has emerged as an effective strategy.Herein,we report the facile development of a Ni_(3)S_(2)-CeO_(2)hybrid nanostructure via an electrodeposition method.Benefiting from the strong interfacial interaction between Ni_(3)S_(2)and CeO_(2),the electron transfer is notably improved and the water oxidation activity of Ni_(3)S_(2)nanosheets is significantly enhanced.In 1.0 M KOH,the Ni_(3)S_(2)-CeO_(2)electrocatalyst achieves a current density of 20 mA cm-2 at a low overpotential of 264 mV,which is 92 mV lower than that of Ni_(3)S_(2).Moreover,Ni_(3)S_(2)-CeO_(2)exhibits superior electrochemical stability.Density functional theory calculations demonstrate that the enhanced OER electrocatalytic performance of Ni_(3)S_(2)-CeO_(2)can be ascribed to an increase in the binding strength of the reaction intermediates at the Ni_(3)S_(2)-CeO_(2)interface.展开更多
The present work is concerned with the voltammetric application of unmodified tricresyl phosphate carbon paste electrode （TCP-CPE） and in situ bismuth-film modified tricresyl phosphate-based carbon paste electrode ...The present work is concerned with the voltammetric application of unmodified tricresyl phosphate carbon paste electrode （TCP-CPE） and in situ bismuth-film modified tricresyl phosphate-based carbon paste electrode （BiF-TCP-CPE）. The TCP-CPE was examined with the main objective of using it for the differential pulse voltammetric analysis of some neonicotinoid insecticides in aqueous Britton-Robinson buffer solution pH 7.0 as supporting electrolyte. After comparing the performance of the TCP-CPE with that of silicone oil carbon paste electrode, quantitative analysis of imidacloprid, thiamethoxam and clothianidin was performed in model solutions and real samples （river water and commercial insecticide formulations）. The in situ prepared BiF-TCP-CPE was tested for a simultaneous detection of selected heavy metal ions （Cd^2＋ and Pb^2＋） at a μg/dm^3 concentration level, using square wave anodic stripping voltammetric technique. The influence of different electrochemical pretreatments of the working electrode on the bismuth deposition and analyte signals were investigated. Film formation was studied at untreated, pre-cathodized and pre-anodized TCP-CPEs in the acetic buffer solution pH 4.6, containing 1 μg/cm^3 Bi （III）.展开更多
In gaseous reduction of iron ore fines, alkaline earth oxides have profound effects on the precipitation behavior of fresh metal- lic iron on the particle surface. In this work, in situ observation was performed to re...In gaseous reduction of iron ore fines, alkaline earth oxides have profound effects on the precipitation behavior of fresh metal- lic iron on the particle surface. In this work, in situ observation was performed to reveal the influence of alkaline earth oxides on the precipitation morphology and micro-structure variation of fresh metallic iron from microscopic level by simulation of the gas-solid reaction condition on the surface of ore particles. Experimental results indicate that doping MgO in the particle surface can inhibit the reduction of iron oxide and however doping CaO, SrO and BaO promote; all alkaline earth oxides tested in this study can change the precipitation morphology of fresh metallic iron; minimum doping mole fraction of one oxide to inhibit iron whiskers growth （ NAO ） is related to its cation radius （ r：＋ ） and its extranuclear electronic layers（nAD ）, which can be expressed as NAO = 1.3 × 10^-5r^2AD,√nA^2.展开更多
Ir-based dectrocatalysts have been system- atically studied for a variety of applications, among which the electrocatalysis for oxygen evolution reaction （OER） is one of the most prominent. The investigation on surf...Ir-based dectrocatalysts have been system- atically studied for a variety of applications, among which the electrocatalysis for oxygen evolution reaction （OER） is one of the most prominent. The investigation on surface-micro- structure-sensitive catalytic activity in different pH media is of great significance for developing efficient electrocatalysts and corresponding mechanism research. Herein, shape-tunable Ir- Pd alloy nanocrystals, including nano-hollow-spheres （NHSs）, nanowires （NWs）, and nanotetrahedrons （NTs）, are synthe- sized via a facile one-pot solvothermal method, Electro- chemical studies show that the OER activity of the Ir-Pd alloy nanocatalysts exhibits surface-microstructure-sensitive en- hancement in acidic and alkaline media. Ir-Pd NWs and NTs show more than five times higher mass activity than com- mercial Ir/C catalyst at an overpotential of 0.25 V in acidic and alkaline media. Post-XPS analyses reveal that surface Ir（VI） oxide generated at surface defective sites of Ir-Pd nanocata- lysts is a possible key intermediate for OER. In acidic medium, the specific activity of Ir-Pd nanocatalysts has a positive cor- relation with the surface roughness of NWs 〉 NHSs 〉 NTs. However, the strong dissociation of surface Ir（VI） species （IrO42-） at surface defective sites is a possible obstacle for the formation of Ir（VI） oxide, which reverses the activity sequence for OER in alkaline medium.展开更多
文摘In the pursuit of stable,high performance Ni-based oxygen evolution reaction(OER)electrocatalysts,modifying the local chemical compositions or fabricating hybrid nanostructures to generate abundant interfaces for improving the water oxidation activity of electrocatalysts has emerged as an effective strategy.Herein,we report the facile development of a Ni_(3)S_(2)-CeO_(2)hybrid nanostructure via an electrodeposition method.Benefiting from the strong interfacial interaction between Ni_(3)S_(2)and CeO_(2),the electron transfer is notably improved and the water oxidation activity of Ni_(3)S_(2)nanosheets is significantly enhanced.In 1.0 M KOH,the Ni_(3)S_(2)-CeO_(2)electrocatalyst achieves a current density of 20 mA cm-2 at a low overpotential of 264 mV,which is 92 mV lower than that of Ni_(3)S_(2).Moreover,Ni_(3)S_(2)-CeO_(2)exhibits superior electrochemical stability.Density functional theory calculations demonstrate that the enhanced OER electrocatalytic performance of Ni_(3)S_(2)-CeO_(2)can be ascribed to an increase in the binding strength of the reaction intermediates at the Ni_(3)S_(2)-CeO_(2)interface.
文摘The present work is concerned with the voltammetric application of unmodified tricresyl phosphate carbon paste electrode （TCP-CPE） and in situ bismuth-film modified tricresyl phosphate-based carbon paste electrode （BiF-TCP-CPE）. The TCP-CPE was examined with the main objective of using it for the differential pulse voltammetric analysis of some neonicotinoid insecticides in aqueous Britton-Robinson buffer solution pH 7.0 as supporting electrolyte. After comparing the performance of the TCP-CPE with that of silicone oil carbon paste electrode, quantitative analysis of imidacloprid, thiamethoxam and clothianidin was performed in model solutions and real samples （river water and commercial insecticide formulations）. The in situ prepared BiF-TCP-CPE was tested for a simultaneous detection of selected heavy metal ions （Cd^2＋ and Pb^2＋） at a μg/dm^3 concentration level, using square wave anodic stripping voltammetric technique. The influence of different electrochemical pretreatments of the working electrode on the bismuth deposition and analyte signals were investigated. Film formation was studied at untreated, pre-cathodized and pre-anodized TCP-CPEs in the acetic buffer solution pH 4.6, containing 1 μg/cm^3 Bi （III）.
基金supported by the National Natural Science Foundation of China and Baosteel (Grant No.50834007)the National Basic Research Program of China (973 Program) (Grant No.2012CB720401)
文摘In gaseous reduction of iron ore fines, alkaline earth oxides have profound effects on the precipitation behavior of fresh metal- lic iron on the particle surface. In this work, in situ observation was performed to reveal the influence of alkaline earth oxides on the precipitation morphology and micro-structure variation of fresh metallic iron from microscopic level by simulation of the gas-solid reaction condition on the surface of ore particles. Experimental results indicate that doping MgO in the particle surface can inhibit the reduction of iron oxide and however doping CaO, SrO and BaO promote; all alkaline earth oxides tested in this study can change the precipitation morphology of fresh metallic iron; minimum doping mole fraction of one oxide to inhibit iron whiskers growth （ NAO ） is related to its cation radius （ r：＋ ） and its extranuclear electronic layers（nAD ）, which can be expressed as NAO = 1.3 × 10^-5r^2AD,√nA^2.
基金supported by the National Natural Science Foundation of China (21573005, 21771009 and 21621061)the National Key Research and Development Program (2016YFB0701100)Beijing Natural Science Foundation (2162019)
文摘Ir-based dectrocatalysts have been system- atically studied for a variety of applications, among which the electrocatalysis for oxygen evolution reaction （OER） is one of the most prominent. The investigation on surface-micro- structure-sensitive catalytic activity in different pH media is of great significance for developing efficient electrocatalysts and corresponding mechanism research. Herein, shape-tunable Ir- Pd alloy nanocrystals, including nano-hollow-spheres （NHSs）, nanowires （NWs）, and nanotetrahedrons （NTs）, are synthe- sized via a facile one-pot solvothermal method, Electro- chemical studies show that the OER activity of the Ir-Pd alloy nanocatalysts exhibits surface-microstructure-sensitive en- hancement in acidic and alkaline media. Ir-Pd NWs and NTs show more than five times higher mass activity than com- mercial Ir/C catalyst at an overpotential of 0.25 V in acidic and alkaline media. Post-XPS analyses reveal that surface Ir（VI） oxide generated at surface defective sites of Ir-Pd nanocata- lysts is a possible key intermediate for OER. In acidic medium, the specific activity of Ir-Pd nanocatalysts has a positive cor- relation with the surface roughness of NWs 〉 NHSs 〉 NTs. However, the strong dissociation of surface Ir（VI） species （IrO42-） at surface defective sites is a possible obstacle for the formation of Ir（VI） oxide, which reverses the activity sequence for OER in alkaline medium.
