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

Abstract

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.

Hydrogen evolution descriptors of 55-atom PtNi nanoclusters and interaction with graphite

“…PtNi alloy nanoparticles are interesting candidates for reducing the amount of Pt in HER catalysts as PtNi/C nanoparticles have been reported to outperform the HER activity of Pt/C benchmark under alkaline conditions [31][32][33]. The incorporation of sulphur to PtNi nanoalloys can enhance HER activity and durability of PtNi catalyst in alkaline seawater [34]. In addition, PtNi alloy nanoparticles have been shown to increase the catalytic activity in oxygen reduction reactions (ORRs) compared to pure platinum [35][36][37], and PtNi clusters have been reported to be highly efficient catalysts for methane dehydrogenation [38].…”

Enhanced d–π overlap in a graphene supported Ni/PtNi heterojunction for efficient seawater hydrogen evolution

“…4–7 In the group investigated thus far, Pt-based materials have been found to possess superior H adsorption properties that make them the most efficient catalyst for the cathodic hydrogen evolution reaction (HER). 8–10 However, it is commonly observed that the alkaline seawater splitting performance of Pt-based catalysts is substantially lower than that in alkaline media, primarily owing to chloride ion-promoted corrosion associated with metal chloride/hydroxide formation (eqn (1)–(3)). 11–13 This highlights an urgent need for new strategies to design high-performance and durable Pt-based electrocatalysts for seawater HER.Pt + Cl − → PtCl ads + e − PtCl ads + Cl − → PtCl x − PtCl x + OH − → Pt(OH) x + Cl − …”