Atomically engineered core-shell OER catalysts from free‐standing oxide membranes

Major efforts in recent years to develop catalysts for the oxygen evolution reaction (OER) have shown that perovskites and spinels have significant catalytic activity, making them a promising materials class for water-splitting for hydrogen production. However, so far these complex oxides have displayed limited stability, which prevents realizing their potential. This activity-stability dilemma is compounded by the fact that most progress on ‘rational catalyst design and property engineering’ so far has focused on model-catalysts, whereas we lack effective strategies to transfer optimized electrocatalysts into realistic electrode assemblies.In ScrambledOxs I propose to overcome these major challenges through a novel approach based on free-standing, core-shell heterostructure catalysts produced by atomically engineered oxide epitaxy. This core-shell heterostructure concept, which I will implement as epitaxial trilayers, will enable me to engineer (with atomic control) a catalytically active core-layer sandwiched between stabilizing shell-layers that enhance the chemical stability, to thereby address the activity-stability dilemma. Crucially, using recently established delamination techniques, which I will further develop in this project, I aim to ‘peel off’ optimized trilayers into freestanding oxide membranes. This will provide two crucial capabilities. First, I will be able conduct detailed operando characterization of the electrochemical processes to enable a knowledge-driven catalyst design. Second, I will be able to fabricate (scramble) the freestanding oxides into atomically defined, core-shell-like nanoflakes that I will integrate into carbon-based inks, to thereby demonstrate transfer of the optimized electrocatalysts from model-system into real electrode environment.In this way, ScrambledOxs will overcome the classical activity-stability dilemma of single phase OER catalysts and bridge the gap between model-catalyst research and applied catalysts research.