Synthesis of copper and cobalt co-doped ZnO nanomaterials: effect of optical property tuning on visible light-driven photocatalytic activity

Doping or co-doping can improve the optoelectronic and structural characteristics of metal oxide semiconductors. Here, the Cu and Co co-doped ZnO nanoparticles (CCZ NPs) were synthesized using the self-propagation approach, which occurs after passing the sol-gel synthesis method. The XRD pattern peak shifts confirmed the doping of Cu and Co in ZnO crystal nanoparticles. The HRTEM d-spacing analysis (0.26 nm (002) and 0.15 nm (220)) indicates the existence of ZnO and CuO crystals as a heterojunction, respectively. The EDS analysis shows the decent distribution of copper and cobalt dopant elements on the ZnO host surface. The improvement in optical properties of the CCZ NPs is verified using UV-vis DRS and PL analyses. The CCZ NPs at a low dopant concentration level demonstrate a higher capability for degrading methylene blue (MB) dye with a rate constant k value of 0.089 min -1 , compared to the pure ZnO NPs ( k = 0.051 min -1 ). The increased performance of the CCZ NPs is mainly attributed to the effective charge separation and enhanced visible light harvesting properties. Thus, CCZ NPs show great potential for the environmental cleanup and decontamination of various pollutants.