Asymmetric Ru─O sites in self-activated catalysts for efficient electrochemical methanol oxidation and industrial-scale hydrogen generation

Abstract

Electrochemical water splitting is a promising strategy for sustainable, large-scale hydrogen production. However, the commercialization of this technology is hindered by the sluggish kinetics and high overpotential of the oxygen evolution reaction (OER) at the anode, leading to elevated energy consumption. Replacing OER with the methanol oxidation reaction (MOR) offers a more energy-efficient alternative, yet the development of electrocatalysts that deliver high activity, selectivity, and long-term stability at ampere-level current densities remains a notable challenge. Here, we report an interface-engineered RuO_x@Mo(Mn)O_x [RuO_x nanoparticles deposited on a Mo(Mn)O_x matrix] catalyst featuring Ru─O sites with an asymmetric coordination environment, which enables optimized electron transfer and stabilization of highly active Ru species. This structural innovation allows for efficient methanol electrooxidation at industrially relevant current densities [1000 milliamperes per square centimeter (mA cm⁻²) at 1.41 volts versus reversible hydrogen electrode], achieving high selectivity (>98% Faradaic efficiency) and low anodic potentials. The RuO_x@Mo(Mn)O_x-based two-electrode electrolyzer maintains 1000 mA cm⁻² at a low cell voltage of 1.58 volts and remains stable for over 300 hours. Furthermore, in an anion exchange membrane electrolyzer, the catalyst demonstrates stable operation at 1000 mA cm⁻² and a cell voltage of only 1.87 volts, highlighting its potential for industrial coproduction of green hydrogen and value-added chemicals. This work demonstrates how interface engineering at the atomic level can enable industrial-scale electrochemical processes with Ru-based catalysts, offering a scalable solution for the advancement of sustainable energy and chemical manufacturing.