Modification of the Electrochemical Surface Oxide Formation and the Hydrogen Oxidation Activity of Ruthenium by Strong Metal Support Interactions

A major hurdle for the wide spread commercialization of proton exchange membrane based fuel cells (PEMFCs) and water electrolyzers are the durability and high cost of noble metal catalysts. Here, alternative support materials might offer advantages, as they can alter the properties of a catalyst by means of a strong metal support interaction (SMSI) that has been shown to prevent platinum oxidation and suppress the oxygen reduction reaction on titanium oxide supported platinum nanoparticles deposited on a carbon support (Pt/TiOx/C). Herein, we report a novel Ru/TiOx/C catalyst that according to tomographic transmission electron microscopy analysis consists of partially encapsulated Ru particles in a Ru/TiOx-composite matrix supported on a carbon support. It is shown by cyclic voltammetry and X-ray photoelectron spectroscopy that ruthenium oxidation is mitigated by an SMSI between Ru and TiOx after reductive heat-treatment (Ru/TiOx/C-2(400 degrees C,H) ). As a result, the catalyst is capable of oxidizing hydrogen up to the onset of oxygen evolution reaction, in stark contrast to a Ru/C reference catalyst. PEMFC-based hydrogen pump measurements confirmed the stabilization of the hydrogen oxidation reaction (HOR) activity on Ru/TiOx/C-2(400 degrees C,H) and showed a approximate to 3-fold higher HOR activity compared to Ru/C, albeit roughly two orders of magnitude less active than Pt/C.

Automated summary

The commercialization of PEMFCs and water electrolyzers is hindered by the durability and high cost of noble metal catalysts. Alternative support materials can alter the properties of a catalyst through SMSI, which can prevent platinum oxidation and suppress oxygen reduction. This study reports a novel Ru/TiOx/C catalyst with partially encapsulated Ru particles in a Ru/TiOx-composite matrix supported on a carbon support. After reductive heat-treatment, the catalyst shows improved stability and activity for the hydrogen oxidation reaction compared to a reference catalyst.