Construction of Visible light Driven Z-Scheme 1D/1D p-CuBi2O4/n-CdWO4 Heterojunction Nanocomposite for Effective Degradation of Organic Pollutants

The effective separation and harnessing of photoinduced charge carriers in photocatalysis are significant challenges. The present study aims to overcome this obstacle by developing a Z-scheme heterojunction between a ptype CuBi2O4 (CBO) and a n-type CdWO4 (CWO) through a straightforward heat treatment method. The powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and High-resolution transmission electron microscopy (HRTEM) results revealed the successful formation of heterostructures. The photocatalytic efficiency of the materials was assessed by selecting an anionic methyl orange (MO) and cationic Rhodamine-B (Rh-B) dyes under visible light irradiation. Among all the materials, 85 wt% CBO + 15 wt% CWO (CBO/CWO-15) heterostructure exhibited superior photocatalytic activity (90 %) corresponding to 90 and 45 times higher than the pristine CBO and CWO, respectively. The positively charged photocatalyst surface attracts a greater number of MO dye molecules than Rh-B, thereby enhancing the degradation of MO over Rh-B. The scavenger results confirmed the involvement of hydroxy (OH center dot) and superoxide (O-2(-center dot)) radicals in the degradation of MO. The rate constant of CBO/CWO-15 (0.01061 min(-1)) was 64 and 39 times higher than those of CBO (0.00016 min(-1)) and CWO (0.00027 min(-1)), respectively. The photoluminescence (PL) and electrochemical impedance spectroscopy (EIS) analyses substantiated the improved charge separation in the CBO/CWO-15 composite, establishing the Z-scheme mechanism. Cycling experiments over four cycles demonstrated consistent stability of the CBO/CWO-15 composite. The study provides an in-detail plausible mechanism of MO degradation. This type of Z-scheme composite material has potential applications in environmental remediation for the effective removal of organic pollutants and antibiotics from wastewater.