Construction of light-sensitive Cu 2 O/Fe 2 O 3 heterostructures to promote photocatalytic CO 2 reduction and photo-assisted charge storage

Designing high-performance bifunctional materials for photo-assisted electrochemical charge storage and photocatalysis is challenging due to the difficulty in balancing electroactivity and photo-to-electric efficiency. Herein, copper foam (CF) supported three-dimensional nanoarrays (3D NAs) composed of copper oxide/iron oxide (Cu 2 O/Fe 2 O 3 ) heterostructures were constructed as bifunctional materials for the photocatalytic CO 2 reduction reaction (CO 2 RR) and photo-assisted supercapacitors. These Cu 2 O/Fe 2 O 3 3D NAs have demonstrated high electroactivity and good light adsorption with high photocurrent responses. As a result, the optimized Cu 2 O/Fe 2 O 3 photocatalyst delivered a high methane (CH 4 ) production rate of 38.6 μmol h −1 g −1 with good cycling stability for the CO 2 RR. When used for photo-assisted supercapacitors, the optimized Cu 2 O/Fe 2 O 3 photoelectrode exhibited a maximum photo-capacitance of 595 F g −1 , delivering an enhancement of 17.3% over the capacitance obtained without light (507 F g −1 ). This work provides a unique approach to utilizing light energy directly to promote electrochemical and photocatalytic properties.