Tuning the Local Environment of Atomic Pt Shells of Pt3Fe@Pt Nanoparticles Enables Energy-Saving Hydrogen Production

Abstract

In this work, small-sized, core-shell structured Pt₃Fe nanoparticles (NPs) with a Pt shell thickness of ~2-3 atomic layers were successfully fabricated. These NPs were oxygen-bridged with abundant Fe single atoms (SAs) and loaded in carbon materials (denoted as CS Pt₃Fe@Pt NP-O-A-Fe SA/C catalyst). The presence of abundant Fe SAs O-bridged to Pt shells of CS Pt3Fe@Pt NP in the CS Pt₃Fe@Pt NP-O-A-Fe SA/C catalyst can tune the local environment of atomic Pt shells. This not only improves their anti-CO poisoning ability during the methanol oxidation reaction (MOR) by reducing the CO adsorption sites and rapidly removing CO from Pt shells, but also enhances the alkaline hydrogen evolution reaction (HER) performance by creating an optimally local acidic environment near the Pt shells. Moreover, the overpotential at a current density of 10 mA cm^-2 (η₁₀) of the CS Pt₃Fe@Pt NP-O-A-Fe SA/C catalyst for the alkaline HER is only 10 mV, which is 30 mV lower than that (40 mV) of the commercial Pt/C catalyst. Furthermore, in the MOR//HER-configured overall water splitting system, an ultra-low cell voltage of 0.574 V at 10 mA cm^-2 for hydrogen production was achieved, with a Faraday efficiency approaching 100%.