Interfacial Sulfur-Sensitization of PtNi Nanoalloy for Efficient Electrocatalytic Hydrogen Production in Alkaline Simulated Seawater

Optimization of the electronic structure and surface physicochemical properties of PtNi nanoalloys by incorporation of sulfur (S) is an effective strategy for improving the efficiency of the electrocatalytic hydrogen evolution reaction (HER). However, few studies have been carried out to assess the seawater electrocatalytic performance of PtNi by incorporation of interfacial S from CdS nanocrystals. In this study, a simple method is developed to prepare CdS/PtNi, composed of a PtNi alloy supported with CdS quantum dots (QDs). Experimental data demonstrate that interfacial S-sensitization enhances the electron density of PtNi nanoalloy in CdS/PtNi. Therefore, CdS/PtNi exhibits superior performance toward HER in seawater. Specifically, CdS/PtNi displays a low overpotential of 22 mV at a current density of 10 mA cm–2, a higher specific activity of 24.7 mA cm–2 at −0.07 V, and superior durability in seawater, all of which metrics exceed those of commercial Pt/C. Theoretical calculations provide additional evidence that interfacial S-sensitization of PtNi alloy raises electron densities, lowers the d-band center, facilitates water molecule adsorption, resistances to Cl–, and reduces the hydrogen adsorption Gibbs free energy of PtNi alloy. This study provides new opportunities for the design of efficient and stable electrocatalysts for large-scale production of hydrogen from seawater.