Dealloying Preparation Of Copper-based Catalysts And Electrocatalytic Oxygen Evolution Performance Research

Oxygen evolution reaction(OER)is the control step in water electrolysis system.The development of transition metal OER catalysts with high activity,high specific surface area and high stability is of great significance.At present,the reported OER activity of Cu-based catalysts is still significantly weaker than that of Ni,Co metal oxides.Therefore,it is still a challenge to develop efficient and stable copper-based oxygen evolution catalysts.The dealloying method can effectively improve the catalyst structure,expose more active sites and improve the catalytic performance.In this essay,self-supporting porous copper-based catalysts was prepared by dealloying method,and its OER catalyst performance was studied.By etching Mg72Cu28,Mg61Cu28Cd11,Mg61Cu28Y11 and further electrochemical anodization,we successfully prepared a series of self-supported porous Cu nanowires(p-CuNWs).SEM shows the electrode surface of p-CNWs was evenly distributed nanowires.XRD and XPS were used to characterize the crystal structure and valence state of the catalyst,which demonstrated the samples were mainly Cu-based hydroxide.The OER activity of p-CuNWs was assessed by electrochemical methods.Among them,Linear scanning voltammetry(LSV)suggested p-CuNWs prepared from Mg72Cu28 owe the highest catalytic activity,With an overpotential of 310 mV to reach a current density of 10 mA cm-2 and a Tafel slope of 85 mV dec-1,besides it can sustainable catalysis for 10 h.Besides,we demonstrated that the morphology of p-CuNWs can be controlled by doping Cd and Y elements.Furthermore,cyclic voltammetry(CV)was used to electrochemically etch Al60Cu36CO4 and Al60Cu40 to prepare p-CuCoOx and p-CuOx catalysts.SEM shows the doping of Co had a significant effect on the morphology of porous Cu-based catalyst,and p-CuCoOx presented a remarkably uniform nano-needle structure.EDS analysis shows that the ratio of Cu and Co atoms of p-CuCoOx electrode is 7:1.The p-CuCoOx catalyst has better OER activity than p-CuOx Under alkaline conditions,when the overpotential is 310 mV,the current density of p-CuCoOx reaches 50 mA cm-2,which is 10 times higher than p-CuOx.Its excellent OER activity is mainly attributed to the "synergy" between Cu and Co.