In order to inhibit hydrogen evolution and enhance current efficiency of Zn-Fe alloy electrodeposition from alkaline zincate solution, hydrogen inhibitors composed of the sulfur group elements were optimized on the ba...In order to inhibit hydrogen evolution and enhance current efficiency of Zn-Fe alloy electrodeposition from alkaline zincate solution, hydrogen inhibitors composed of the sulfur group elements were optimized on the basis of atom structures analysis. The effects of hydrogen inhibitor on the current efficiency of Zn-Fe alloy electroplating and their electrochemical behaviors were studied. The results indicate that hydrogen inhibitor can increase the current efficiency of Zn-Fe alloy electroplating evidently, from 63.28% without hydrogen inhibitor up to 83.54% with a hydrogen inhibitor at a volume fraction of 2.0%, while it has a minor influence on that of pure Zn plating, which maintains at 80%. The optimum volume fraction of hydrogen inhibitor is 2.0%.展开更多
Ni睱a alloy coating was prepared by electrodeposition. The effect of cathodic current density on the La content of the alloy coatings was discussed. It is found that the content of La in the alloy increases with incre...Ni睱a alloy coating was prepared by electrodeposition. The effect of cathodic current density on the La content of the alloy coatings was discussed. It is found that the content of La in the alloy increases with increasing the cathodic current density. The microstructures and codeposition mechanism of Ni La alloy coatings were investigated by means of X ray diffraction (XRD) and cyclic voltammetry (CV). The results demonstrate that the Ni La alloy is FCC and codeposited by the induced mechanism. The hydrogen evolution reaction (HER) on the electrodeposited Ni La alloy electrodes in alkaline solution was evaluated by Tafel polarization curves. It is found that La Ni alloy coating exhibites much higher exchange current density for HER than pure Ni electrode, and that the exchange current density increases with increasing the La content of alloys. The good electrocatalytic activity for HER of this Ni La alloy is attributed to the synergism of the electronic structure of La and Ni. The electrodeposited La Ni alloys have a certain electrochemical hydrogen storage capacity of 34 ～ 143?mAh/g, which increases with increasing the La content of alloys.展开更多
A cobalt-iron alloy thin-film electrode-based electrochemical hydrogen-phosphate-ion sensor was prepared by electrodepositing on an Au-coated Al2O3 substrate from an aqueous solution of metal-salts. The use of a cobal...A cobalt-iron alloy thin-film electrode-based electrochemical hydrogen-phosphate-ion sensor was prepared by electrodepositing on an Au-coated Al2O3 substrate from an aqueous solution of metal-salts. The use of a cobalt-iron alloy electrode greatly improved the hydrogen-ion sensor response performance, i.e., the sensor worked stably for more than 7 weeks and showed a quick response time of several seconds. Among the cobalt and iron alloy systems tested, the electrodeposited Co58Fe42 thin-film electrode showed the best EMF response characteristics, i.e., the sensor exhibited a linear potentiometric response to hydrogen-phosphate ion at the concentration range between 1.0 × 10–5 and 1.0 × 10–2 M with the slope of –43 mV/decade at pH 5.0 and at 30℃. A sensing mechanism of the Co-based potentiometric hydrogen-phosphate ion sensor was proposed on the basis of results of instrumental analysis.展开更多
Ni-W alloys and their composite deposits are electroplated on the metals when an appropriate complex agent is selected on the base of the theories of electrochemistry and complex chemistry, and the principle of induce...Ni-W alloys and their composite deposits are electroplated on the metals when an appropriate complex agent is selected on the base of the theories of electrochemistry and complex chemistry, and the principle of induced codeposition. Effects of the bath composition, pH value, temperature and current density on the electrode position of Ni-W alloys and their composite deposits have been investigated, and the effect of heat treatment temperature on the hardness, structure and cohesive force of the amorphous Ni-W alloys and their composite deposits are also discussed. Results showed that the alloys containing more than 44 wt pct W content and the composite deposits containing 7.8 wt pct SiC content could be obtained by making use of the appropriate bath composition and plating conditions. Alloys and their composite deposits with over 44 wt pct W content show amorphous structure. The hardness of amorphous Ni-W alloys and their composite deposits increases obviously when heated, and can reach to 1350 HV and 1520 HV respectively for 46 wt pct W content. The cohesion on Cu, carbon steel and stainless steel is very good.展开更多
In this work,three-dimensional hierarchical nickel–cobalt alloy coating for hydrogen evolution cathode was fabricated by electrodeposition processes.The coatings’morphology evolves from sea cucumber-like nanostructu...In this work,three-dimensional hierarchical nickel–cobalt alloy coating for hydrogen evolution cathode was fabricated by electrodeposition processes.The coatings’morphology evolves from sea cucumber-like nanostructure to caterpillar-like one with the increase of cobalt content.A large amount of nanometric‘‘steps,’’served as the active sites for hydrogen evolution reaction,were observed.According to Tafel polarization measurements,the exchange current density of the as-synthesized coating with hierarchical nanostructure was 21.9 times compared with that of flat nickel coating.In addition,the hierarchical coating also displayed good electrochemical stability from the galvanostatic test.展开更多
Nanocrystalline Ni Mo Fe alloy deposits were obtained by electrodeposition. The structures of the alloy deposits were analyzed by X ray diffraction (XRD) and X ray photoelectron spectroscopy (XPS). The XRD results...Nanocrystalline Ni Mo Fe alloy deposits were obtained by electrodeposition. The structures of the alloy deposits were analyzed by X ray diffraction (XRD) and X ray photoelectron spectroscopy (XPS). The XRD results of nanocrystalline Ni Mo Fe alloy deposit show that many diffraction lines disappear, and that there is only one diffraction peak at 44.0°. The XPS results of nanocrystalline Ni Mo Fe alloy deposits indicate that the nickel, molybdenum and iron of the deposits exist in metallic state, and that the binding energy of the alloyed elements increases to some extent. The nanocrystalline Ni Mo Fe alloy deposit electrode may offer better electrocatalytic activity than the polycrystalline nickel electrode and the nanocrystalline Ni Mo alloy electrode. The electrochemical impedance spectra from the nanocrystalline Ni Mo Fe alloy electrode indicate that hydrogen evolution in 30% ( m/m ) KOH at lower overpotential is in accordance with the Volmer Tafel mechanism, but with the Volmer Heyrovsky mechanism at higher overpotential.展开更多
A new pretreatment method has been developed to improve the catalytic activity of the Ni-Fe-Mo-Co alloy electrode for hydrogen evolution reaction （HER）. The procedure involves pre-electrolyzing the Ni-Fe-Mo-Co alloy...A new pretreatment method has been developed to improve the catalytic activity of the Ni-Fe-Mo-Co alloy electrode for hydrogen evolution reaction （HER）. The procedure involves pre-electrolyzing the Ni-Fe-Mo-Co alloy electrode in 30% KOH solution containing 10% potassium sodium tartrate at 70℃ for 2 h, until some of the Mo and Fe elements are leached out. The surface morphology of the Ni-Fe-Mo-Co alloy demonstrates a unique hive-like structure after the pre- treatment, which has the pore size in a nanometer range （about 50 nm）, a very large real surface area, and good stability. The results of the electrochemical studies show that compared to other similar electrode materials and the treated Ni-Fe-Mo-Co electrode by leaching method, the pre-treated Ni-Fe-Mo-Co electrode has a much lower overpotential and much higher exchange current density for HER. In addition, a long-term continuous electrolysis test with a current interruption shows that the Ni-Fe-Mo-Co alloy has excellent catalytic stability.展开更多
Mechanism of electrodeposition nickelcobalt alloy and electrocatalytic properties of hydrogen evolution of nickelcobalt obtained in a sulfate bath with or without rare earth compounds were studied.The experimental...Mechanism of electrodeposition nickelcobalt alloy and electrocatalytic properties of hydrogen evolution of nickelcobalt obtained in a sulfate bath with or without rare earth compounds were studied.The experimental results showed that the process of nickelcobalt alloy belonged to"anomalous codeposition".By measuring the cathodic polarization curves,the surface structure and the components of nickelcobalt alloy,when a small amount of rare earth compounds was added to the bath,the cathodic polarization of electrodepositing process was decreased,the alloy coatings gained from the bath containing Ce(SO4)2 became higher in the electrocatalytic properties of hydrogen evolution in 7mol·L-1 KOH and roaser in grain size and less in cobalt content.展开更多
基金Project(50274073) supported by the National Natural Science Foundation of China
文摘In order to inhibit hydrogen evolution and enhance current efficiency of Zn-Fe alloy electrodeposition from alkaline zincate solution, hydrogen inhibitors composed of the sulfur group elements were optimized on the basis of atom structures analysis. The effects of hydrogen inhibitor on the current efficiency of Zn-Fe alloy electroplating and their electrochemical behaviors were studied. The results indicate that hydrogen inhibitor can increase the current efficiency of Zn-Fe alloy electroplating evidently, from 63.28% without hydrogen inhibitor up to 83.54% with a hydrogen inhibitor at a volume fraction of 2.0%, while it has a minor influence on that of pure Zn plating, which maintains at 80%. The optimum volume fraction of hydrogen inhibitor is 2.0%.
文摘Ni睱a alloy coating was prepared by electrodeposition. The effect of cathodic current density on the La content of the alloy coatings was discussed. It is found that the content of La in the alloy increases with increasing the cathodic current density. The microstructures and codeposition mechanism of Ni La alloy coatings were investigated by means of X ray diffraction (XRD) and cyclic voltammetry (CV). The results demonstrate that the Ni La alloy is FCC and codeposited by the induced mechanism. The hydrogen evolution reaction (HER) on the electrodeposited Ni La alloy electrodes in alkaline solution was evaluated by Tafel polarization curves. It is found that La Ni alloy coating exhibites much higher exchange current density for HER than pure Ni electrode, and that the exchange current density increases with increasing the La content of alloys. The good electrocatalytic activity for HER of this Ni La alloy is attributed to the synergism of the electronic structure of La and Ni. The electrodeposited La Ni alloys have a certain electrochemical hydrogen storage capacity of 34 ～ 143?mAh/g, which increases with increasing the La content of alloys.
文摘A cobalt-iron alloy thin-film electrode-based electrochemical hydrogen-phosphate-ion sensor was prepared by electrodepositing on an Au-coated Al2O3 substrate from an aqueous solution of metal-salts. The use of a cobalt-iron alloy electrode greatly improved the hydrogen-ion sensor response performance, i.e., the sensor worked stably for more than 7 weeks and showed a quick response time of several seconds. Among the cobalt and iron alloy systems tested, the electrodeposited Co58Fe42 thin-film electrode showed the best EMF response characteristics, i.e., the sensor exhibited a linear potentiometric response to hydrogen-phosphate ion at the concentration range between 1.0 × 10–5 and 1.0 × 10–2 M with the slope of –43 mV/decade at pH 5.0 and at 30℃. A sensing mechanism of the Co-based potentiometric hydrogen-phosphate ion sensor was proposed on the basis of results of instrumental analysis.
文摘Ni-W alloys and their composite deposits are electroplated on the metals when an appropriate complex agent is selected on the base of the theories of electrochemistry and complex chemistry, and the principle of induced codeposition. Effects of the bath composition, pH value, temperature and current density on the electrode position of Ni-W alloys and their composite deposits have been investigated, and the effect of heat treatment temperature on the hardness, structure and cohesive force of the amorphous Ni-W alloys and their composite deposits are also discussed. Results showed that the alloys containing more than 44 wt pct W content and the composite deposits containing 7.8 wt pct SiC content could be obtained by making use of the appropriate bath composition and plating conditions. Alloys and their composite deposits with over 44 wt pct W content show amorphous structure. The hardness of amorphous Ni-W alloys and their composite deposits increases obviously when heated, and can reach to 1350 HV and 1520 HV respectively for 46 wt pct W content. The cohesion on Cu, carbon steel and stainless steel is very good.
基金sponsored by National Natural Science foundation of China(No.21303100)Shanghai Natural Science Foundation(No.13ZR1420400)
文摘In this work,three-dimensional hierarchical nickel–cobalt alloy coating for hydrogen evolution cathode was fabricated by electrodeposition processes.The coatings’morphology evolves from sea cucumber-like nanostructure to caterpillar-like one with the increase of cobalt content.A large amount of nanometric‘‘steps,’’served as the active sites for hydrogen evolution reaction,were observed.According to Tafel polarization measurements,the exchange current density of the as-synthesized coating with hierarchical nanostructure was 21.9 times compared with that of flat nickel coating.In addition,the hierarchical coating also displayed good electrochemical stability from the galvanostatic test.
基金theNationalNaturalScienceFoundationofChina (No .2 0 0 73 0 3 7)theMajorStateBasicResearchDevelopmentProgram (No .2 0 0 2CBZ 1180 0 )
文摘Nanocrystalline Ni Mo Fe alloy deposits were obtained by electrodeposition. The structures of the alloy deposits were analyzed by X ray diffraction (XRD) and X ray photoelectron spectroscopy (XPS). The XRD results of nanocrystalline Ni Mo Fe alloy deposit show that many diffraction lines disappear, and that there is only one diffraction peak at 44.0°. The XPS results of nanocrystalline Ni Mo Fe alloy deposits indicate that the nickel, molybdenum and iron of the deposits exist in metallic state, and that the binding energy of the alloyed elements increases to some extent. The nanocrystalline Ni Mo Fe alloy deposit electrode may offer better electrocatalytic activity than the polycrystalline nickel electrode and the nanocrystalline Ni Mo alloy electrode. The electrochemical impedance spectra from the nanocrystalline Ni Mo Fe alloy electrode indicate that hydrogen evolution in 30% ( m/m ) KOH at lower overpotential is in accordance with the Volmer Tafel mechanism, but with the Volmer Heyrovsky mechanism at higher overpotential.
文摘A new pretreatment method has been developed to improve the catalytic activity of the Ni-Fe-Mo-Co alloy electrode for hydrogen evolution reaction （HER）. The procedure involves pre-electrolyzing the Ni-Fe-Mo-Co alloy electrode in 30% KOH solution containing 10% potassium sodium tartrate at 70℃ for 2 h, until some of the Mo and Fe elements are leached out. The surface morphology of the Ni-Fe-Mo-Co alloy demonstrates a unique hive-like structure after the pre- treatment, which has the pore size in a nanometer range （about 50 nm）, a very large real surface area, and good stability. The results of the electrochemical studies show that compared to other similar electrode materials and the treated Ni-Fe-Mo-Co electrode by leaching method, the pre-treated Ni-Fe-Mo-Co electrode has a much lower overpotential and much higher exchange current density for HER. In addition, a long-term continuous electrolysis test with a current interruption shows that the Ni-Fe-Mo-Co alloy has excellent catalytic stability.
文摘Mechanism of electrodeposition nickelcobalt alloy and electrocatalytic properties of hydrogen evolution of nickelcobalt obtained in a sulfate bath with or without rare earth compounds were studied.The experimental results showed that the process of nickelcobalt alloy belonged to"anomalous codeposition".By measuring the cathodic polarization curves,the surface structure and the components of nickelcobalt alloy,when a small amount of rare earth compounds was added to the bath,the cathodic polarization of electrodepositing process was decreased,the alloy coatings gained from the bath containing Ce(SO4)2 became higher in the electrocatalytic properties of hydrogen evolution in 7mol·L-1 KOH and roaser in grain size and less in cobalt content.
