Gas phase synthesis and controlled atmosphere electrochemical analysis of oxygen evolution electrocatalysis of CaxSr1‑xFe2O6‑δ perovskites where δ = 0-1, will be discussed. This system exhibits a wide range of activity depending on the A site composition. Our results suggest that surface and subsurface oxygen content controls the oxygen evolution catalysis. Although, current understanding from the d-orbital electron count (eg occupancy) predicts low OER activities for such a system, under specific solution conditions, some of the compounds in the Sr2-xCaxFe2O6-δ series exhibit higher activity than LaCoO3. We particularly use results of in-situ vibrational spectroscopy and electrochemical analysis to elucidate vacancy content and ordering effects on catalysis.
We will also discuss the influence of surface and subsurface structures of model Pt-M (M = Cu and Ni) surface alloys and bilayers during hydrogen adsorption relevant to hydrogen evolution reaction (HER). We use electrochemical measurements and in-situ surface stress analysis of these systems to elucidate activity trends from hydrogen adsorption affinities. Our results exhibit a correlation between the energetics of hydrogen underpotential deposition and HER catalytic activity.