Anode Photovoltage Compensation‐Enabled Synergistic CO2 Photoelectrocatalytic Reduction on a Flower‐Like Graphene‐Decorated Cu Foam Cathode

Abstract An interconnected and hierarchically structured electrode composed of a Cu nanoparticle‐modified flower‐like reduced graphene oxide‐decorated copper foam (Cu NP/f‐RGO/CF) is crafted and exploited for photoelectrocatalytic (PEC) reduction of CO 2 in a TiO 2 nanotube photoanode‐driven PEC cell. Anode photovoltage compensation confers a more negative cathode potential for CO 2 reduction, thus leading to a synergistic effect between photocatalysis (PC) and electrocatalysis (EC). CO 2 reduction rate under PEC condition is 5.4× higher than that of the simple sum under PC and EC processes. The well‐defined flower structure of RGO in the CF scaffold effectively prevents its self‐agglomeration, which increases its adsorption towards CO 2 with improved electron‐transfer kinetics due to the 3D interconnected structure with abundant electron transfer pathways. DFT calculations further reveal the absorption and activation of CO 2 on Cu NP/f‐RGO capitalize on the CC bond with RGO and OCu bond with Cu NPs, thereby leading to a bended and stretched structure. The enhanced CO 2 adsorptivity and activation on the hierarchical Cu NP/f‐RGO/CF electrode significantly improve CO 2 reduction and facilitate the conversion of C1 products to high‐order products. This research highlights the great prospect of anode photovoltage compensation enables synergistic photoelectrocatalysis and 3D hierarchical electrode for CO 2 drastic reduction into high‐order products.