Binder-free bifunctional SnFe sulfide/oxyhydroxide heterostructure electrocatalysts for overall water splitting

Developing robust non-noble catalysts towards hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is vital for large-scale hydrogen production from electro-chemical water splitting. Here, we synthesize Sn-and Fe-containing sulfides and oxy-hydroxides anchored on nickel foam (SnFeSxOy/NF) using a solvothermal method, in which a heterostructure is generated between the sulfides and oxyhydroxides. The SnFeSxOy/NF exhibits low overpotentials of 85,167, 249, and 324 mV at 10,100, 500 and 1000 mA cm-2 for the HER, respectively, and a low overpotential of only 281 mV at 100 mA cm-2 for the OER. When it serves as both anode and cathode to assemble an electrolyzer, the cell voltage is only 1.69 V at 50 mA cm-2. The sulfides should be the efficient active species for the HER, while the oxyhydroxides are highly active for the OER. The unique sulfide/oxyhydroxide heterostructure facilitates charge transfer and lowers reaction barrier, thus promoting electrocatalytic processes.(c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.