Sulfur Recovery Assisted Electrochemical Water Splitting for H2 Production Using CoMo-Based Nanorod Arrays Catalysts

Swapping the sluggish oxygen evolution reaction (OER) for the thermodynamically advantageous sulfur ion oxidation reaction (SOR) makes it possible to produce low-energy hydrogen. We report here on an electrocatalytic SOR-coupled HER system that allows for the joint production of sulfur and hydrogen. We prepare a CoMoO4 nanoarray on nickel foam (NF) for anodic SOR and N-doped CoMoO4/NF, CoMoN/NF, for cathodic HER. The current density of 100 mA cm–2 was obtained at 0.29 V (vs RHE) in the SOR process. After nitridation, the electrode can achieve a current density of 10 mA cm–2 in HER at a voltage of only 32 mV (vs RHE). The coupling system (SOR//HER) can run steadily for 150 h. Detailed exploration and discussion were conducted on the pathways of SOR. This work develops an energy-efficient mixed water electrolysis system for H2, providing a viable option for toxic waste treatment.