CO₂ Reduction Using Chalcogen-Modified Copper Materials and Nanoclusters: Progress and Challenges

Surface modification with chalcogens has emerged as a powerful means of controlling catalyst activity and selectivity in copper-based catalysts. For example, incorporation of chalcogens has led to enhanced selectivity in CO₂ electroreduction to high-value, high-density liquid products including ethanol, propanol, acetic acid, and methanol. There are few other catalysts capable of producing these products at such high selectivities, highlighting the significance of chalcogen doping for these transformations. Still, further improvements remain challenging because of the difficulties in obtaining active site uniformity and gaining an atomically precise structural and mechanistic understanding about the active sites. As such, much recent research has been devoted to the development of atomically precise nanoclusters for use in catalysis. Despite significant advances in the synthesis and application of gold nanoclusters for catalysis, catalytic studies of copper nanoclusters remain underexplored. Herein, we summarize recent progress and challenges associated with the development of both chalcogen-modified copper surfaces and copper nanoclusters for the electro- and photocatalytic reduction of CO₂.