Sn-based redox cycle mediated microenvironment regulation of Cu sites on poly(ionic liquid) enhance electrocatalytic CO-to-C2+ conversion

Electrocatalytic CO reduction provides a sustainable route for high-value CO utilization. To promote the selectivity of C2+ products (FEC2+) at high reaction rates, the electronic structure and the microenvironment of Cu sites in Cu@PIL were regulated by introducing a Sn-mediated redox cycle. The obtained Cu@PIL@Sn-x hybrids provided high FEC2+ (> 70%) within a wide current density (j) range from –100 to −700 mA cm–2. Particularly, an excellent FEC2+ of 96.8 % with a high jC2+ of −484.2 mA cm–2 was obtained on Cu@[email protected]. Besides, it exhibited high tolerance of diluted CO gas at −250.0 mA cm–2. Mechanistic studies demonstrated the rich high-valence Cu species and the adjacent Sn-Cl species at the Cu@PIL@Sn-x hybrids jointly account for the local enrichment of oxygen-containing species on Cu surface during the electrolysis of CO, even at high overpotentials, which enables the C–C coupling at high reaction rates.