Acidic CO2 Electroreduction to formic acid at low overpotential over Cu modified by dual sites polymer

Abstract

Acidic CO2 electroreduction to HCOOH provides a promising strategy for renewable energy storage and CO2 recycling. However, under acidic condition, it typically exhibits poor selectivity at low overpotential. Here, we report the first work that the CO2 can be efficiently reduced into HCOOH over Cu catalyst by modifying with a dual sites polymer at acidic condition. The selectivity of HCOOH is significantly enhanced at low overpotential, the Faradaic efficiency (FE) of HCOOH can reach 87.4% with an energy efficiency (EE) of 56%. This is the highest EE for HCOOH at acidic condition to date. Experiments and density functional theory (DFT) calculations revealed that the dual sites in polymer can promote CO2 reduction and stabilize the key intermediate *OCHO, resulting in high selectivity of HCOOH at low overpotential.