Unveiling the Ni–S synergy in 3D porous carbon-supported NiS nanoparticles for enhanced oxygen evolution

Abstract

Despite the remarkable intrinsic activity and cost-effectiveness of nickel-sulfur (Ni–S) diatomic electrocatalysts, their widespread industrial adoption in water splitting systems remains hindered by an incomplete understanding of the synergistic interplay between nickel and sulfur species. To address this challenge, we developed a facile NaCl-template-assisted strategy combined with sequential carbonization and sulfidation processes, yielding three-dimensional porous carbon nanosheets embedded with NiS nanoparticles (NiS/PCNs). The optimized NiS/PCNs catalyst demonstrates superior alkaline oxygen evolution reaction (OER) performance, achieving a current density of 10 mA cm⁻² at a low overpotential of 210 mV in 1 M KOH, accompanied by a favorable Tafel slope of 69 mV dec⁻¹ and exceptional durability (99 % activity retention over prolonged operation). Moreover, DFT calculations reveal an innovative “aggregation-rebalance” mechanism governing Ni–S interactions. This dynamic process induces electron redistribution across metallic surfaces, facilitating charge convergence and transfer dynamics. Consequently, the energy barrier of the OER rate-determining step is substantially reduced, rationalizing the enhanced catalytic efficiency of NiS nanoparticles. This work achieves dual advancements: A scalable synthesis route for constructing three-dimensional porous architectures with optimized mass/charge transport capabilities; Fundamental elucidation of atomic-level Ni–S synergy through computational-experimental integration. The proposed design paradigm extends beyond Ni–S systems, offering a universal framework for developing transition metal chalcogenide electrocatalysts.