Silk fibroin-derived carbon aerogels embedded with copper nanoparticles for efficient electrocatalytic CO-to-CO conversion.

Metal-carbon matrix catalyst has attracted a great deal of interest in electrochemical carbon dioxide reduction reaction (CORR) due to its excellent electrocatalytic performance. However, the design of highly active metal-carbon matrix catalyst towards CORR using natural biomass and cheap chemical precursors is still under challenge. Herein, a self-assembly strategy, along with CO gas as acidifying agent, to fabricate silk fibroin (SF) derived carbon aerogels (CA) combining trace copper nanoparticles (SF-Cu/CA) is developed. Zinc nitrate was introduced as a pore-forming agent to further optimize the pore structure of the as-prepared catalysts to form SF-Cu/CA-1. The rich mesoporous structure and unique constitute of SF-Cu/CA-1 is conducive to exposed numerous active sites, fast electron transfer rate, and the desorption of *CO intermediate, thus leading to the electrocatalytic CORR of SF-Cu/CA-1 catalyst with an excellent current density of 29.4 mA cm, Faraday efficiency of 83.06% towards carbon monoxide (CO), high the ratio value of CO/H (19.58), and a long-term stability over a 10-hour period. This performance is superior to that of SF-Cu/CA catalyst (13.0 mA cm, FE=58.43%, CO/H = 2.16). This work not only offers a novel strategy using natural biomass and cheap chemicals to build metal-carbon matrix catalyst for electrocatalytic CO-to-CO conversion, but also is expected to promote the industrial-scale implementations of CO electroreduction.