Interface Engineering of AuCu Bimetallic Nanoparticles/1T-MoS2 Electrocatalyst for Enhanced Hydrogen Evolution Reaction Activity in Natural Seawater and Alkaline Freshwater

Developing robust, high-performance electrochemical catalysts for hydrogen production from natural seawater or alkaline freshwater presents a significant challenge. Herein, we report an electrocatalyst system of AuCu bimetallic nanoparticles (NPs) supported on 1T-MoS2 (AuCu/1T-MoS2) synthesized via hydrothermal/solvothermal methods followed by controlled electrochemical deposition. Experimental electrochemical measurements combined with density functional theory (DFT) calculations reveal that the AuCu/1T-MoS2 catalyst exhibits superior hydrogen evolution reaction (HER) activity in alkaline freshwater compared with natural seawater. DFT indicates that adsorption of Na+ or Cl– on the active Au sites makes the Gibbs free energy of hydrogen adsorption (ΔGH) more negative, thereby disfavoring H2 desorption and reducing activity in seawater. Experimentally and theoretically, the introduction of AuCu NPs increases the density of accessible active sites by activating the otherwise inert basal planes of 1T-MoS2. The Cu component facilitates water dissociation and lowers ΔGH, while Au improves the electrical conductivity. The orbital hybridization between the d states of AuCu and those of Mo in 1T-MoS2 results in a higher density of states at the Fermi level, thereby improving conductivity and reducing ΔGH. Charge redistribution at the AuCu/1T-MoS2 interface produces a synergistic enhancement of HER kinetics. Our findings offer design principles for bimetallic/2D hybrid electrocatalysts tailored for seawater and alkaline electrolysis.