Exclusive CO₂-to-formate conversion over single-atom alloyed Cu-based catalysts

Electrochemical CO₂ reduction reaction (CO₂RR), powered by renewable energy sources, provides an appealing approach to convert emitted CO₂ to value-added chemicals and fuels and achieve a carbon-neutral cycle. Among various carbon-based products, formic acid (HCOOH) has been considered as a promising liquid hydrogen storage material due to its high energy density and hydrogen content. However, so far, the reported HCOOH-selective catalysts (e.g., Bi, Sn, In, Pb and Pd) have failed in either activity (< 500 mA cm^-2) or stability (< 20 h), which significantly inhibits the industrialized feasibility of CO₂RR. In contrast, Cu takes the advantages of excellent activity and low cost, making it more commercially viable. To date, one of the most challenging issues of Cu-based catalysts lies in unsatisfactory selectivity, that is, tending to produce mixed products rather than specific one, due to the complicated reaction paths involved. Very recently, Zheng et al. have developed a single-atom alloy (SAAs) strategy for the exclusive CO₂-to-formate conversion over Cu-based catalysts. The as-prepared Pb single-atom alloyed Cu catalyst (Pb₁Cu) (Fig. 1a) exhibited near unity selectivity towards HCOOH and impressive stability, providing the prospect of industrial production of HCOOH from CO₂.