Galvanic replacement-induced preparation of bloom-like Pt23Ni77 for methanol coupled efficient hydrogen production

Abstract

Galvanic replacement reaction (GRR) leverages the difference in metal reduction potentials to regulate the structure of nanomaterials. The crucial aspect of constructing highly active catalysts lies in the precise manipulation of both the oxidative dissolution of sacrificial template metals and reductive deposition of alternate metals. Herein, we investigated the morphological transformation of metal Ni as a sacrificial template in the presence of different amounts of H₂PtCl₆ solution and the Pt⁴⁺ substitution of Ni to achieve the redistribution of elements on the catalyst surface, which provides superior performance in both the methanol oxidation reaction (MOR) and hydrogen evolution reaction (HER). The uniform distribution of Pt on a three-dimensional transition metal Ni substrate allows for the complete exposure of the noble metal to the catalyst surface. This distribution increases the reaction area, facilitating easy access for reactants and promoting electron transfer. Meanwhile, Pt (1.39 Å) has a larger atomic radius compared to Ni (1.24 Å), and the substitution reaction in the transition metal phase induces strong compressive strain, which effectively regulates the electronic structure of Ni.