A High Entropy Oxide Designed to Catalyze CO Oxidation Without Precious Metals.

The chemical complexity of single-phase multicationic oxides, commonly termed high entropy oxides (HEOs), enables the integration of conventionally incompatible metal cations into a single-crystalline phase. However, few studies have effectively leveraged the multicationic nature of HEOs for optimization of disparate physical and chemical properties. Here, we apply the HEO concept to design robust oxidation catalysts in which multicationic oxide composition is tailored to simultaneously achieve catalytic activity, oxygen storage capacity, and thermal stability. Unlike conventional catalysts, HEOs maintain single-phase structure, even at high temperature, and do not rely on the addition of expensive platinum group metals (PGM) to be active. The HEOs are synthesized through a facile, relatively low temperature (500 °C) sol-gel method, which avoids excessive sintering and catalyst deactivation. Nanostructured high entropy oxides with surface areas as high as 138 m