Metal nanoparticles decorated CoFe-(oxy)hydroxysulfides nanosheets fabricated by a general strategy for electrocatalytic water splitting

This study presents a novel method to fabricate metal-decorated, sulfur-doped layered double hydroxides (M/SLDH) through spontaneous redox and sulfurization processes. The developed Ag/SLDH and Pt/SLDH catalysts with abundant heterogeneous interfaces and hierarchical nanostructures demonstrated outstanding oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) performance, achieving low overpotentials of 212 and 35 mV at 10 mA cm −2 in 1 M KOH, respectively. As both anode and cathode in water splitting, they required only 1.47 V to reach 10 mA cm −2 and exhibited high structural robustness, maintaining stability at 1000 mA cm −2 for 300 h. In-situ Raman analysis revealed that the synergistic effects of metal nanoparticles and S doping significantly promote the transformation into the S-Co 1− x Fe x OOH layer, which serves as the active phase for water oxidation. Additionally, ultraviolet photoelectron spectroscopy (UPS) and density functional theory (DFT) analyses indicated that incorporating metal nanoparticles and S doping increase electron density near the Fermi level and reduce reaction energy barriers, thus enhancing intrinsic OER and HER activities. This study provides a scalable strategy for synthesizing high-performance electrocatalysts for water splitting, with promising potential for broader applications.