Nd-Doped MoS₂Nanosheets with Sulfur Vacancies as Catalysts for Hydrogen Evolution

A key challenge in the field of the hydrogen evolution reaction (HER) is to develop catalysts that not only perform well in pure alkaline conditions but also maintain high efficiency in simulated seawater, which poses additional complexities due to the presence of salts. This study introduces Nd-doped MoS 2 nanosheets on carbon cloth (Mo 1– x Nd x S 2 ⊥CC) as a high-performance electrocatalyst tailored for the HER in both saltwater and alkaline water. The optimized catalyst demonstrates an exceptional overpotential of 112 mV at a current density of 10 mA/cm 2, which is significantly lower than the 235 mV exhibited by pristine MoS 2 under the same conditions. Density functional theory (DFT) calculations and experimental data indicate that Nd doping enhances the catalytic performance by creating oxophilic sites that improve water adsorption and dissociation, as well as by modulating the electronic structure of MoS 2 to accelerate both the alkaline Volmer and Heyrovsky reaction kinetics. Additionally, sulfur vacancy (Sv) further strengthens the interaction between Nd and S, enhancing water activation and lowering the dissociation barrier. The catalyst maintains over 95% of its initial activity after 48 h of operation in simulated seawater, underscoring its excellent stability and effectiveness. These advancements in catalyst design not only address the pressing need for robust HER catalysts in variable electrolytes but also underscore the broader applicability of metal-doped MoS 2 to other transition metals like Ru, Mn, and Fe, potentially enhancing HER across diverse operational environments.