Self-standing 2D tin-sulfide-based heterostructured nanosheets: An efficient overall urea oxidation catalyst

In this work, SnS/SnS₂ heterostructured film on a nickel foam (NF) through solution process was grown and employed directly as cathode and anode to the urea oxidation reaction (UOR). The as-fabricated SnS/SnS₂ film achieves high efficiency toward UOR with a lower potential of 1.38 V vs RHE to deliver 50 mA cm⁻², which is approximately 200 mV less than the potential demanded for the oxygen evolution reaction (OER). More importantly, the electrolyzer consisting of two identical electrodes with the SnS/SnS₂/NF ǁ SnS/SnS₂/NF vs RHE assembly oxidizes urea at a lower potential of 1.36, 1.38, and 1.39 V vs RHE to deliver a current density of 10, 50, and 100 mAcm⁻², respectively. The superior UOR performance of the SnS/SnS₂-based electrode is attributed to the combined merits of the SnS and SnS₂ phases in the heterostructure, enhancing the catalytic active sites and providing the easy charge transport between the electrode and electrolyte.