Metal atom-modified nickel hydroxysulfide for highly efficient electrocatalytic overall water splitting

Abstract

The design and fabrication of high-performance, low-cost, and durable bifunctional electrocatalysts are crucial for addressing energy crises. However, significant challenges remain. In this study, we employ an oxidation-etching strategy to synthesize metal atom-modified nickel hydroxysulfide (NiSOH) (M = Fe, Cu, Co, Mn, Ce), offering advantages in simplicity, cost-effectiveness, and efficiency. Experimental results demonstrate that metal doping significantly enhances the catalytic performance of NiSOH. Notably, the bifunctional Cu–NiSOH electrode exhibits low overpotentials of 238 mV (η₁₀₀) for the hydrogen evolution reaction (HER) and 289 mV (η₁₀₀) for the oxygen evolution reaction (OER). Structural characterization using TEM, SEM, XRD, and XPS reveals that metal doping optimizes the microstructure, increasing the contact area between the catalyst and the electrolyte, thereby facilitating electrolyte infiltration and gas release. Additionally, DFT calculations and experimental data confirm that the incorporation of Cu atoms significantly enhances electrocatalytic activity. This work highlights the crucial role of metal atoms in improving catalytic performance and presents an effective strategy for designing metal-doped hydroxysulfides as high-performance electrocatalysts.