Importance of Surface IrO in Stabilizing RuO for Oxygen Evolution.

The high precious metal loading and high overpotential of the oxygen evolution reaction (OER) prevents the widespread utilization of polymer electrolyte membrane (PEM) water electrolyzers. Herein we explore the OER activity and stability in acidic electrolyte of a combined IrO/RuO system consisting of RuO thin films with submonolayer (1, 2, and 4 Å) amounts of IrO deposited on top. Operando extended X-ray absorption fine structure (EXAFS) on the Ir L-3 edge revealed a rutile type IrO structure with some Ir sites occupied by Ru, IrO being at the surface of the RuO thin film.

Operando XAS Study of the Surface Oxidation State on a Monolayer IrO on RuO and Ru Oxide Based Nanoparticles for Oxygen Evolution in Acidic Media.

Herein we present surface sensitive operando XAS L-edge measurements on IrO/RuO thin films as well as mass-selected RuO and Ru nanoparticles. We observed shifts of the white line XAS peak toward higher energies with applied electrochemical potential. Apart from the case of the metallic Ru nanoparticles, the observed potential dependencies were purely core-level shifts caused by a change in oxidation state, which indicates no structural changes.

Oxygen evolution on well-characterized mass-selected Ru and RuO nanoparticles.

Oxygen evolution was investigated on model, mass-selected RuO nanoparticles in acid, prepared by magnetron sputtering. Our investigations include electrochemical measurements, electron microscopy, scanning tunneling microscopy and X-ray photoelectron spectroscopy. We show that the stability and activity of nanoparticulate RuO is highly sensitive to its surface pretreatment.

Enabling direct H2O2 production through rational electrocatalyst design.

Future generations require more efficient and localized processes for energy conversion and chemical synthesis. The continuous on-site production of hydrogen peroxide would provide an attractive alternative to the present state-of-the-art, which is based on the complex anthraquinone process. The electrochemical reduction of oxygen to hydrogen peroxide is a particularly promising means of achieving this aim.