S-doped Au/Pd/Pt aerogels becoming superior HER catalysts by constructing an atomic-scale Pd diffuse interface

Abstract

In this work, an S_6.5-doped Au_77.6/Pd_0.8/Pt_15.1 aerogel with a structure composed of an Au core, an atomic-scale Pd diffuse interface and a Pt shell was successfully prepared by adopting an unconventionally low Pd-to-Pt precursor molar ratio of 1 : 20. It was found that the atomic-scale Pd diffuse interface in the aerogel greatly promoted the electron transfer from Au and Pt, which optimized the desorption ability of the active sites to H* by properly downshifting the d-band center of Pt. Besides this effect, an appropriate amount of PtS doped in the Pt shell achieved the construction of a local acidic-like environment during the alkaline HER process and significantly accelerated H₂O-dissociation. Accordingly, the as-prepared S_6.5-doped Au_77.6/Pd_0.8/Pt_15.1 aerogel showed excellent performance towards both the alkaline HER (η₁₀ = 9 mV, Δη₁₀ = 65 mV vs. commercial Pt/C catalysts and Tafel slope = 26.5 mV dec⁻¹) and the acidic HER (η₁₀ = 2 mV, Δη₁₀ = 27 mV vs. commercial Pt/C catalysts and Tafel slope = 12.3 mV dec⁻¹). Moreover, it displayed an outstanding long-term durability towards the alkaline and acidic HERs.