Preparation of Highly Efficient All-pH Bifunctional Water Electrolysis Catalysts Through a Surface Modification Strategy

Abstract

Electrolytic hydrogen production from water is a very promising technology, and catalysts capable of efficient operation over a wide pH range are essential for energy storage and conversion. Herein, a trace Ru catalytic core restructures nickel foam (NF) under polymeric protection, with temperature gradient control forming HER-active metal monomers at low temperatures and OER-suitable oxides at high temperatures. It is demonstrated that the surface modification strategy can help NF to maintain its own backbone structure during the carbonation process and that the resulting catalysts possess excellent properties. The synthesized catalysts-Ru@NF-KPDA-550 exhibit the lowest OER overpotentials of 183 mV in 0.5 M H₂SO₄ and 151 mV in 1.0 M KOH, and Ru@NF-KPDA-350 exhibits the lowest HER overpotentials of 11.8 mV in 0.5 M H₂SO₄ and 13.4 mV in 1.0 M KOH for Ru@NF-KPDA-350 at 10 mA cm⁻². The DFT simulations show that the synergistic interaction between Ru and Ni components, which optimizes their d-band centers, enhances the HER and OER pathways, thereby lowering activation barriers and boosting catalytic performance. This work provides a viable strategy for the design of pH-universal electrocatalysts for the overall water splitting.