Copper Oxide Unlocks Cryogenic Carbon Monoxide Oxidation

Performing oxidation reactions at low temperatures using earth-abundant materials is crucial for advancing solutions for sustainable chemistry. Carbon monoxide (CO) oxidation serves as a benchmark reaction to characterize oxidation and to advance fundamental concepts in surface chemistry. While there are several examples of CO oxidation occurring on metal oxides at low temperatures, from 300 K to ~200 K, reactivity in the cryogenic temperature regime typically requires a metal nanoparticle on a metal oxide.

A recent breakthrough has challenged this conventional wisdom. Researchers have demonstrated that oxygen atoms on the (111) facet of cuprous oxide (Cu₂O) react with carbon monoxide to form carbon dioxide at temperatures below 100 K. This discovery, combining spectroscopic experimental evidence with calculations, proposes a low barrier path for CO oxidation at reconstructed surface sites on Cu₂O(111).

This finding is particularly significant because it addresses the challenge of achieving cryogenic reactivity with earth-abundant materials. As lead author Karagoz notes in the paper, "This finding is a rare example of an earth-abundant metal oxide, in this case copper, that can provide highly reactive multifunctional sites, enabling both adsorption and reaction fundamental steps toward the efficient heterogeneous oxidation of chemicals." This demonstration of Cu₂O's capacity to facilitate both adsorption and reaction steps points towards new strategies for efficient heterogeneous oxidation, offering a more sustainable and cost-effective approach to chemical processing than systems typically requiring precious metals.