Anchoring ruthenium single atoms into the carbon nanotubes-supported nickel-based sulfides for enhanced electrocatalytic oxygen evolution.

Engineering single atoms anchored on nanoparticles with maximal atom utilization efficiency and tunable coordination character holds a great promise for applications in water splitting and energy storage. Herein, Ruthenium (Ru) single atoms embedded in nickel subsulfide‑nickel sulfide (NiS-NiS) nanoparticles supported on carbon nanotubes (CNTs) are fabricated via economical approach and utilized as chemical catalysts towards oxygen evolution reaction (OER). The unique architecture of Ru@NiS-NiS/CNTs provides substantial surface area exposure, facilitating electron transport and revealing numerous active sites. In particular, Ru@NiS-NiS/CNTs demonstrates remarkable OER catalytic capability, with a reduced overpotential of 221 mV at 10 mA cm and decreased Tafel slope of 74.1 mV dec in alkaline electrolyte, outstripping commercially available Ir/C catalyst. The atomically dispersed Ru sites were identified and the Ru single atoms confined within the NiS-NiS lattice of it to induce Ru-S-Ni bonding, serving as catalytic centers to elevate the inherent activity towards OER. Furthermore, the electronic characteristic of NiS-NiS was modulated with the doping of isolated Ru atoms. Density functional theory (DFT) calculations have illustrated the presence of atomically dispersed Ru into NiS-NiS strengthens both chemical adsorption and OER catalytic activities. This study broadens significant insights into the field of single-atom catalysts and offers valuable perspectives for designing advanced materials in sustainable energy applications.