Ultralow Pt-Loaded Pt/Fe2O3 with Pt−Fe Pair Sites for Efficient Seawater Hydrogen Production

Abstract

Seawater electrolysis for green hydrogen production urgently demands high-performance electrocatalysts that simultaneously deliver fast reaction kinetics with robust chloride ion (Cl−) resistance. Herein, we report an ultralow Pt-loaded (<1 wt %) Pt/Fe2O3 catalyst rich in Pt−Fe atomic pairs synthesized via a photoreduction synthetic strategy. Photogenerated electrons drive the selective reduction of Pt precursors at low-coordinate Fe3+ sites on α-Fe2O3 (012) facets, constructing Pt−Fe pair interfaces that enable directional electron transfer from Fe-dz2 to Pt-dz2 orbitals. This electronic modulation optimizes the Gibbs free energy of hydrogen adsorption, weakens the intrinsic affinity of active sites toward Cl−, and accelerates water dissociation. The as-synthesized catalyst achieves ultralow overpotentials of 9 and 51 mV at 10 and 100 mA cm−2 respectively in alkaline simulated seawater, with a slight potential decay of only 0.08 mV h−1 over 1000 h of continuous operation, outperforming most state-of-the-art electrocatalysts. When integrated into an anion exchange membrane electrolyzer, it delivers a low cell voltage of 2.0 V at 500 mA cm−2 and maintains stable operation for 200 h at 100 mA cm−2.