Controlled synthesis of M doped NiMoO4 (M = Co, Cu and Fe) for urea, freshwater and seawater oxidation reaction

Electrocatalytic splitting of urea or seawater for hydrogen production has become one of the most promising methods. In this paper, different foreign ions M (M = Co, Cu and Fe) are introduced into this NiMoO4 material by hydrothermal and impregnation methods. Their electrocatalytic properties were investigated in different electrolytes, such as urea, pure water and seawater. What is noteworthy is that the Co-NiMoO4/NF electrode exhibited superior urea oxidation properties (1.32 V @ 10 mA cm−2). The different reaction mechanisms result in the superior water oxidation performance of this Fe3+-NiMoO4/NF material. What is noteworthy is that the durability of the material needs to be improved. The promoted performance is attributed to rapid electron transfer and improved electrical conductivity. Density functional theory (DFT) also shows that this Fe-NiMoO4/NF electrode presents optimal water adsorption energy and improved electrical conductivity, thus improving the catalytic activity of the material because of introduction of Fe. The work provides novel views for the design of environmentally friendly and inexpensive multifunctional catalysts for urea, freshwater and seawater splitting reaction.