Bioinspired Electrocatalytic CO2 Reduction by Bovine Serum Albumin-Capped Silver Nanoclusters Mediated by [-SiW12O40]4-

Silver nanoclusters capped with bovine serum albumin (AgNC@BSA) were synthesized and applied for the electrocatalytic reduction of CO2. Inspired by the fact that many enzymes function only in the presence of coenzymes/cofactors that transfer electrons/protons or other groups, an electron transfer mediator was introduced to facilitate the electrical communication between the electrode and the strongly protected catalyst. The AgNC@BSA catalyst mediated by [-SiW12O40](4-) anions showed high electrocatalytic activity for CO2 reduction, which was not observed with either component on its own, in dimethylformamide containing 1% (v/v) water. CO was the major product with excellent faradaic efficiency (>75%). The onset potential for this catalytic CO2 reduction process is about 400mV more positive than that found at a bulk silver electrode. This mediator-enhanced catalysis concept provides a general approach to investigate the electrocatalytic activities of nanoclusters, which remain largely unexplored.