A Z-scheme CdS/BiVO4 photocatalysis towards Eriochrome black T: An experimental design and mechanism study

Abstract

The synergistic photocatalytic activity was obtained when CdS and BiVO4 nanoparticles (NPs) were coupled. The samples were characterized by XRD, FTIR, SEM-EDX, and UV-DRS techniques, and their pHpzc was also estimated. The crystallite size of the coupled sample was estimated at 37.3 and 12.5 nm by the Scherrer and Williamson-Hall equations, respectively. The band gaps and the potential positions of VB and CB levels of the semiconductors used were determined. The highest boosted photocatalytic activity was obtained when the CdS: BiVO4 mole ratio was 1:1. RSM studied the simultaneous interactions between the selected variables, and the model F-value of 110.61> F0.05, 14, 13 = 2.4 accompanied by the LOF F-value of 5.20 < F0.05, 10, 3 = 8.79 confirm the model significance. The correlation coefficients of R2 = 0.9861, the adjusted R2 = 0.9710, and the predicted R2 = 0.9417, also establish a satisfactory model for processing the experimental data. In the scavenging agent study, photodegradation mechanisms were suggested; among them, the direct Z-scheme mechanism is more favorable for illustrating the EBT-photodegradation by the binary CdS–BiVO4 photocatalyst. The proposed system, especially the direct Z-scheme mechanism, is suitable as a potential hydrogen production system.