Phosphorus-induced interfacial electric field reconstruction enhances pH-universal hydrogen evolution on Ru/TiO2

Abstract

Ruthenium (Ru) is a promising alternative to platinum for the hydrogen evolution reaction (HER), but its activity is hindered by strong hydrogen adsorption in acid and sluggish water dissociation in alkali. Here we present a phosphorus (P)-doped Ru/TiO2 catalyst (P–Ru/TiO2) that achieves pH-universal HER activity through coupled electronic and electrostatic modulation. P incorporation forms Ru–P and P–O–Ti linkages, enriching Ru with electrons and reorganizing the interfacial electric double layer (EDL). The strengthened EDL enhances proton accessibility and hydrogen spillover under acidic conditions, while facilitating water activation and continuous OH- removal in alkaline media. Differential capacitance, zeta potential, in situ Raman, and density functional theory analyses reveal that P doping optimizes interfacial charge distribution and hydration structure. The catalyst also exhibits excellent stability, sustaining over 100 h of continuous operation in both proton exchange membrane and anion exchange membrane water electrolyzers, highlighting its potential for durable, pH-universal hydrogen production.