Improved photocatalytic activity of zinc oxide through the formation of novel ternary tungsten trioxide/carbon nanotube/zinc oxide composite photocatalyst

•Formation of novel WO3/CNT/ZnO photocatalyst was affirmed with XRD, FTIR and HRTEM.•The WO3/CNT/ZnO photocatalyst achieved complete degradation of MB and BSA.•The rate of photodegradation was increased with higher loading of WO3. This study aimed to resolve the inherent limitation of zinc oxide (ZnO) and produce a highly efficient photocatalyst through the formation of a novel ternary tungsten trioxide (WO3)/carbon nanotubes (CNT)/ZnO composite photocatalyst via sol-gel and deposition methods. The presence of WO3 and CNT enhances the photocatalytic activity of the ternary composite photocatalyst toward degradation of MB and BSA. The rate and efficiency of the photodegradation were elevated with increasing loading of WO3. This can be ascribed to the lower band gap energy, effective charge separation and charge transfer supplied CNT, and the Z-scheme heterojunction formed in the ternary composite photocatalyst. The highest photodegradation rate was attained by the 11 wt% WO3/CNT/ZnO composite photocatalyst in which a complete degradation of MB and BSA were achieved in 120 and 150 min, respectively. The ternary composite photocatalyst demonstrated a good stability by maintaining at least 95% of MB degradation after four consecutive cycles.