Preparation of nickel-manganese based bimetallic hydroxide nanosheets for enhanced electrocatalytic oxygen evolution reaction

This paper uses a common one-step hydrothermal method to prepare NiMn-LDH/NF (Layered Double Hydroxide, LDH) oxygen evolution catalyst with outstanding performance. The NiMn-LDH grows into a nanosheet array structure on nickel foam (NF) and it has a big surface area and exceptional ion transport function that could accelerate the diffusion rate of electrocatalytic products. It attempted to modulate the molar proportion of Ni and Mn to explore the oxygen evolution reaction (OER) performance of the NiMn-LDH/NF catalysts. It was found that when Ni:Mn=4:1 (molar ratio, hereinafter), the nanosheets grew more densely and had better OER performance and stability. The electrochemical test results show that the Ni4Mn-LDH/NF catalyst exhibits an overvoltage of 341 mV at a current density of 10 mA cm−2, and the Tafel slope is only 98.99 mV dec−1.