Direct methanol oxidation at low overpotentials using Ptnanoparticles electrodeposited at ultrathin conductive RuO2 nanoskins

Abstract

Small (primarily 2–4 nm) Pt nanoparticles electrodeposited at Ti-supported RuO₂ nanoskins, designated as Pt/RuO₂(Ti), are highly active for electrocatalytic oxidation of methanol (CH₃OH) in acid electrolyte, with peak potentials among the lowest reported anywhere for RuO₂-supported Pt. The Pt-modified RuO₂ nanoskin is equally effective for CH₃OH oxidation whether one or both sides of the Ti-foil substrate is coated or whether the RuO₂ nanoskin is electrolessly deposited at the Ti substrate as a single layer or in multiple layers. Current densities for methanol oxidation are ∼2× lower than previously reported, owing to a bimodal distribution of both highly active (2–4 nm) and less active larger (> 5 nm) Pt particles. The methods reported here comprise a means of expressing highly active, nanostructured, bifunctional electrocatalytic coatings on substrates of essentially any geometry and minimizing the quantity of RuO₂ necessary.