Phase transition in V-doped cobalt hydroxide for efficient oxygen evolution and urea oxidation reaction

Abstract

In this work, many kinds of V doped Co(OH)2 electrodes were in situ synthesized on Ni foam by a one-step typical hydrothermal process. It is worth noting that the phase transition composition of the V doped Co(OH)2 material can be modulated by the difference of the amount of the V introduced. Different crystal phase compositions show different water oxidation activities. It is worth noting that the V2–Co(OH)2/NF electrode shows better oxygen evolution performance (Overpotential of 320 mV@50 mA cm−2) compared with Co(OH)2/NF (450 mV@50 mA cm−2), V1–Co(OH)2/NF (340 mV@50 mA cm−2) and V3–Co(OH)2/NF (350 mV@50 mA cm−2) electrodes. The experimental results show that not all doping can improve the electrochemistry performance of electrodes, such as the oxidation of urea. Density functional theory calculation further proves that the doping of the V is favorable to the adsorption of water and inhibits the adsorption of urea. This study provides a new idea for the development of efficient overall water splitting catalysts.