Non-noble metal single-atom catalysts: controllable fabrication and electrocatalytic CO₂ reduction activity

The electrochemical CO₂ reduction reaction (eCO₂RR) was recognized as a pivotal carbon emission reduction technology, as it can couple with renewable energy to convert CO₂ into high-value-added products. With their ultrahigh atomic utilization efficiency, well-defined active sites, and tunable electronic structures, single-atom catalysts (SACs) have demonstrated remarkable catalytic merits and thus exhibited enormous development potential in this field. This minireview summarizes the latest advances in SACs for eCO₂RR. First, the state-of-the-art characterization techniques for single-atom catalysts were discussed, followed by an elaboration on the influence of different synthetic strategies on their performance. Subsequently, the focus was placed on various non-noble metal SACs, with an analysis of the role of catalytic site structures in optimizing the adsorption/desorption energies of intermediates and suppressing the hydrogen evolution side reaction (HER). Finally, the current challenges and prospects of SACs in eCO₂-RR were addressed.