Optimal Design of Copper-Doped ZnO Heterostructures for Photocatalytic and Photoeletrochemical Performance: A Combined Experimental and DFT Study

Development of heterojunction materials is an efficient approach for enhancing photocatalytic and photoelectrochemical processes. We develop a ZnO/CuO heterojunction via Cu doping into a ZnO matrix. Structural characterization confirmed that Cu was effectively incorporated into ZnO without any structural changes. The improved optical properties and reduced charge carrier recombination of the doped samples were confirmed by PL, EIS, and TRPL analyses. DFT was used to characterize the modified electronic properties of the materials. The optimal sample (ZnO with 3 wt % Cu) exhibited a photocurrent density of 2.05 mA/cm 2 at the onset potential of 0.60 V vs Ag/AgCl (1.21 V vs RHE), which is four times superior to that of bare ZnO. As an application, a complete photocatalytic degradation of methylene blue dye was observed by the optimal sample, attributed to synergy between ZnO and CuO, induced by appropriate Cu-doping.