Beyond Leverage in Activity and Stability toward CO₂ Electroreduction to Formate over a Bismuth Catalyst

Abstract

The direct production of formate from CO2 over Bi-based catalysts offers a promising route for producing important chemicals using renewable electricity. Nevertheless, limited by the unstable structure and states of catalysts under electrochemical conditions, electroreduction of CO2 to formate is still facing a trade-off between activity and stability, especially at high current densities. Herein, we reported a metal–carbon interfacial modulation strategy to synthesize the cross-linked and defective carbon-modified Bi nanoparticle (Bi-DC) catalyst with a stable spatial structure and a unique CO2-philic and hydrophobic interface. As a result, the Bi-DC featured a remarkable ability for CO2 electroreduction to formate in a near neutral electrolyte (1 M KHCO3) and was even comparable to the CO2-to-formate activity in the strongly basic systems, along with a high partial current density and formation rate for formate of −378 mA cm–2 and 7 mmol cm–2 h–1, respectively. Also, it achieved a stable electrolysis for 120 h at 0.4 A in a membrane electrode assembly reactor and even operated stably at an industrial large current of 5 A. The carbon species promoted the reconstruction and dispersion of active component Bi, together with a spatial confinement effect that facilitated the formation of formate and achieved stable long-term electrolysis.