Efficient Methanol Electrooxidation Catalyzed by Potentiostatically Grown Cu-O/OH(Ni) Nanowires: Role of Inherent Ni Impurity

Complete electrooxidation of methanol in alkaline conditions is catalyzed efficiently by 3d transition metal-based oxides and hydroxides with no issues of mass-transport limitations. Among them, the oxides and hydroxides of Cu prepared using various methods were said to be exceptional. In this work, the methanol oxidation reaction (MOR) activity of such a copper oxide/hydroxide catalyst is advanced by making use of the three-dimensional (3D) configuration of the Cu foam substrate and inherent Ni impurity present in it. The 3D configuration of the Cu foam substrate enabled a larger active surface area per unit geometrical area. The MOR current densities 110 and 310 mA cm(-2) at 0.60 and 0.75 V vs Hg/HgO, respectively, testify the outstanding MOR activity of Cu-O/OH nanowires with Ni impurity (Cu-O/OH(Ni)). Excellent chronoamperometric stability at 0.55 V vs Hg/HgO and relatively lower activation energy at all potentials in the catalytic turnover region further ascertain the superiority of Cu-O/OH(Ni). Specific activity measurements implied that Cu-O/OH(Ni) benefited from intrinsic activity enhancement by the presence of inherent Ni impurity. This work, thus, reveals a facile way of enhancing the MOR activity of Cu-based MOR electrocatalysts.

Automated summary

Efficient catalysis of methanol electrooxidation in alkaline conditions was achieved using 3d transition metal-based oxides and hydroxides, with copper oxides and hydroxides demonstrating exceptional activity. By utilizing the 3D configuration of a copper foam substrate and the inherent nickel impurity present, the copper oxide/hydroxide catalyst showed outstanding methanol oxidation reaction (MOR) activity, as evidenced by high current densities and excellent stability. The presence of nickel impurity led to intrinsic activity enhancement, showcasing the potential for facile enhancement of Cu-based MOR electrocatalysts.