Controllable synthesis of Pt-rich shell/Mx core [M = Ni, Fe, Co] metal aerogels as efficient electrocatalysts for hydrogen evolution reaction

Abstract

Water electrolysis for hydrogen production offers a solution to the fossil fuel crisis, relying heavily on electrocatalysts for the hydrogen evolution reaction (HER). Fortunately, metal aerogels (MAs) with three-dimensional network structures reveal great potential as HER electrocatalysts. However, their simple synthesis and widespread application still present significant challenges. Here, PtNix MAs electrocatalysts, by controlling the Ni/Pt feeding ratio and using NaBH4 reduction, are prepared via a simple one-step method. Notably, PtNi4 MAs with Pt-rich shell/Ni core structure exhibit excellent HER property, showing a low overpotential of 16.3 mV at 10 mA cm−2 and a mass activity density of 2.28 A mgPt-1 at 70 mV. The outstanding HER properties of PtNi4 MAs are ascribed to the synergistic catalytic effect of Pt and Ni, the core–shell structure of the sample, and the abundant three-dimensional network porosity. Density functional theory (DFT) demonstrates that PtNi4 MAs’ core–shell structure have the lowest dissociation energy of H2O and ΔGH* on the catalyst surface. Furthermore, the replacement of non-precious metal (Ni/Fe/Co) does not affect the formation of the Pt-rich shell structure. Opposite the substitution of reducing agent species affects the formation of Pt-rich shell structure. This work can offer valuable insights for the future sustainable energy applications of MAs materials.