Photoelectrocatalytic reduction of CO₂ to methanol over CuFe₂O₄@PANI photocathode

The present study was aimed to convert CO₂ into methanol which not only addresses the potential solution for controlling the CO₂ concentration level in the atmosphere but also offers an alternative approach for the production of renewable energy source. In this perspective, a hybrid photocatalyst, PANI@CuFe₂O₄ was synthesized, characterized and used as a photocathode for photoelectrocatalytic (PEC) reduction of CO₂ to methanol in aqueous medium at an applied potential of −0.4 V vs NHE under visible light irradiation. The combination of PANI with CuFe₂O₄ greatly increased the PEC CO₂ reduction to methanol owing to enhance the CO₂ chemisorption capacity by the photocathode surface and at the same time facilitated the separation of photogenerated electron-hole (e⁻/h⁺) pairs. The incident photon to current efficiency (IPCE) and quantum efficiency (QE) for methanol formation in PEC CO₂ reduction could be achieved as 7.1 and 24.0% respectively. The rate of formation of methanol in PEC CO₂ reduction was found as 49.3 μmol g⁻¹h⁻¹ with 73% Faradaic efficiency. Compared to photocatalytic reaction, the PEC results demonstrated that the applied potential could effectively separate the photogenerated e⁻/h⁺ pairs and therefore, enhanced the PEC CO₂ reduction activity of the hybrid photocatalyst.