Photoanode driven photoelectrocatalytic system for CO2 reduction to formic acid based on lattice-dislocated Bi nanosheets cathode

Abstract

In the context of carbon neutrality, the efficient conversion of CO₂ is an ideal approach to solving current environmental deterioration and energy shortages. Conversion of CO₂ to HCOOH through a photoelectrochemical (PEC) approach is efficient and green. However, achieving efficient PEC reduction of CO₂ to HCOOH within a wide potential window remains a challenge. In this work, the photoelectrochemical system was constructed using a C_xN_y/BiVO₄ photoanode and lattice-dislocated Bi (LD-Bi) nanosheets to achieve efficient and stable PEC reduction of CO₂ to HCOOH. The PEC tests indicated that the Faraday efficiency of HCOOH (FE_HCOOH) of the system was up to 93.8% at a cell voltage of −2.2 V, and FE_HCOOH still maintained 85.7% after five cycles of experiments. Under the optimal cell voltage of −2.2 V, the system achieved excellent stability for 10 h. In addition, a series of electrochemical characterization techniques indicated that the improvement of water oxidation performance is conducive to the efficient reduction of CO₂ to HCOOH. Based on Bi-based nanomaterials, the work achieves an efficient reduction of CO₂ to HCOOH through the synergistic effect of photoanode and cathode, which provides certain ideas for efficient conversion of CO₂.