High Performance Hydrogen Evolution Reaction Catalyst Based on Single-Walled Carbon Nanotubes Decorated by RuO_x Nanoparticles

We report a cathode material based on plasma-treated single-walled carbon nanotubes decorated by RuO_x nanoparticles using atomic layer deposition. We have examined cathode performance towards hydrogen evolution reaction by tailoring material wettability, conductivity yielded by plasma treatment, and the catalyst loading. We discuss that nucleation of particles is facilitated by the appearance of carboxylic and hydroxyl groups triggered by oxygen plasma action. The best performance is associated with samples containing RuO_x particles of 4–5 nm, which show hydrogen evolution onset potential to be about −5 mV (vs. RHE) in 0.5 M H₂SO₄ measured at a current density of −1 mA cm⁻² and Tafel slope of 47.5 mV/dec. The material possesses stable performance at −10 mA cm⁻² with a potential of about −160 mV.