High Throughput Exsolution Design of CO2 Reduction Reaction Interface in a Copper/High-Entropy Oxide Tandem Electrode

Abstract The entropy design paradigm is yielding advanced materials for many societally crucial applications. While most work focuses on single-phase materials, there are vast opportunities to integrate entropy-designed materials into novel composites. Here we develop a nanocomposite design strategy using exsolution-self-assembly to fabricate Cu nanorods in an entropy-stabilized oxide. Atomic-scale electron probes and energetic calculations elucidate how exsolution-self-assembly is tunable using knowledge of point defect interactions. We leverage this to then demonstrate a high-throughput synthesis and screening strategy to fabricate a library of Cu-ESO tandem CO2 reduction reaction (CO2RR) electrodes. Electrocatalytic mapping and localized physicochemical analyses reveal structure-property relationships between local Cu valence and CO2RR activity, identifying operating potentials and electrode surface chemistries that favor CO2RR over competitive hydrogen evolution. This high-throughput synthesis-screening approach can accelerate development of advanced electrocatalysts and nanocomposite materials for many applications given its compatibility with entropy-designed materials and physical vapor deposition at/near silicon volume manufacturing temperatures.