N-doped carbon nanocage-anchored bismuth atoms for efficient CO reduction.

Electrochemical CO reduction (CORR) is a prospective but challenging method to decrease the CO concentration in the current atmosphere; in particular, the poor selectivity of the target product CO and large overpotentials limit its efficiency. Herein, we propose a top-down route to synthesize Bi single atoms (SAs) anchored by N-doped carbon (NC) nanoboxes starting from BiOCl nanoplates as the hard templates. In the CORR, the obtained Bi single-atom catalyst possesses remarkably-enhanced catalytic performance, achieving a maximal Faraday efficiency (FE) of 91.7% at -0.6 V, which is much higher than that of NC-supported Bi nanoparticles (NPs). Further investigations point out that the enhancement can be attributed to the unique coordination structure of the Bi SAs, as well as the fascinating properties of NC that can efficiently promote the electron transfer during the electro-catalysis.