Mott Schottky CoSx-MoOx@NF heterojunctions electrode for H2 production and urea-rich wastewater purification

The sluggish kinetics of oxygen evolution reaction (OER) is the bottleneck of alkaline water electrolysis. The urea oxidation reaction (UOR) with much faster kinetics was to replace OER. To further promote UOR, a heterojunction structure assembled of CoSx and MoOx was established, and then its superior catalytic activity was predicted by DFT calculation. After that, an ultra-thin CoSx-MoOx@nickel foam (CoSx-MoOx@NF) electrode with a Mott-Schottky structure was prepared via a facile hydrothermal method, followed by a low-temperature vulcanization. Results highlighted CoSx-MoOx@NF electrode presented a superior performance toward UOR, OER, and H2 evolution reaction (HER). Notably, it exhibited excellent electrocatalytic performance for OER (1.32 V vs. RHE, 10 mA cm-2), UOR (1.305 V vs. RHE, 10 mA cm-2), and urea-assisted overall water splitting with a low voltage (1.38 V, 10 mA cm-2) when CoSx-MoOx@NF electrode served as both anode and cathode. It is promising to use CoSx-MoOx@NF in an electrochemical system integrated with H2 generation and urea-rich wastewater purification.