Studies On Preparation And Oxygen Evolution Properties Of Carbon Supported Noble Metal-oxide Composite Anodes For Water Electrolysis

The Hydrogen production by the means of alkaline water electrolysis has been widely used. However, one of the major problems for the water electrolysis is the high potential associated with an oxygen evolution reaction (OER) that occurs at the anode. The higher energy consumpution is the main obstacle for the industrialization of alkaline water electrolysis, over20%of which is consumed to overcome the overpotential An effective electrocatalyst can reduce the overpotential and thus enhance the energy effciency. And the study and development of anode electrocatalyst with high performance is probably the best way to solve the problems. In the present work, carbon supported noble metal, carbon supported oxide and carbon supported noble metal-oxide electrocatalyst were prepared by chemical deposition method and intermittent microwave heating method, respectively. The electrocatalytic activity for the oxygen evolution reaction was evaluated using electrochemical analytic methods.The Pt/C, Pd/C and Au/C electrocatalysts were prepared by chemical deposition noble metal nanoparticles on carbon black using excess0.01M NaBH4solution. The ratios of metal and carbon black were1.3:2and2.3:2. The NiO/C, Co3O4/C and Mn3O4/C electrodes also were prepared by intermittent microwave heating method. The ratios of oxide and carbon black were1.3:2and2.3:2. The metal-oxide/C electrocatalysts were prepared by chemical deposition noble metal nanoparticles on oxide/C powder. All these electrocatalysts were characterized by XRD, TEM and EDS. LSV and chronoamperometry at0.7V revealed that the order of catalytic activity is Pd/C>Pt/C>Au/C and NiO/C>Co3O4/C>Mn3O4/C. Besides, the Au-Co3O4/C(wt1.3:1:2), Au-NiO/C(wt1.3:1:2) and Pt-Mn3O4/C(wt1.3:1:2) electrocatalysts shows the superior catalytic activity for OER during water electrolysis.The onset potential and Oxygen evolution overpotential at2mA cm-2on Au-Co3O4/C(wt1.3:1:2) are0.332V and0.389V respectively, which are74mV and83mV more negative than that on Co3O4/C(wt1:2). At the end of the chronoamperometry at0.7V, the residual current on Au-Co3O4/C(wt1.3:1:2) is4.54mA cm-2, which is4times more than that on Co3O4/C(wt1:2).Similarly, the onset potential and Oxygen evolution overpotential at2mA cm-2on Au-NiO/C(wt1.3:1:2) are0.343V and0.382V respectively, which are6mV and23mV more negative than that on NiO/C(wt1:2). At the end of the chronoamperometry at0.7V, the residual current on Au-NiO/C(wt1.3:1:2) is still6.13mA cm-2, which is1.8times more than that on NiO/C(wt1:2).The onset potential and Oxygen evolution overpotential at2mA cm-2on Pt-Mn3O4/C(wt1.3:1:2) are0.322V and0.391V respectively, which are111mV and120mV more negative than that on Mn3O4/C(wt1:2). At the end of the chronoamperometry at0.7V, the residual current on Pt-Mn3O4/C(wt1.3:1:2) is1.12mA cm-2, which is3times more than that on Mn3O4/C(wt1:2).