Facile in-situ construction of plate-on-plate structured Bi2MoO6/BiOI Z-scheme heterojunctions enriched with oxygen vacancies for highly efficient photocatalytic performances

Novel Bi2MoO6/BiOI plate-on-plate porous Z-scheme heterostructures (BMI PHs) enriched with oxygen vacancies (OVs) were synthesized via an ion exchange approach accompanied by the in-situ growth process. A possible formation process of BMI PHs was studied systemically, depicting the procedures of erosion and growth of Bi2MoO6 nanoplates (NPs) in-situ on the surface of BiOI NPs, indicating the crucial role of Bi2MoO6 in influencing the microstructure and photocatalytic ability of BMI PHs. BMI PHs exhibited a significantly improved visible-light photocatalytic performance in comparison with BiOI and Bi2MoO6 towards the degradation of Rhodamine B (RhB) and inactivation of Pseudomonas aeruginosa (P. aeruginosa), which can be ascribed to the construction of Z-scheme heterojunction and abundant OVs, resulting in the accelerated separation of photoinduced charge carriers and more powerful redox capacity. Among them, BMI-0.5 can remove almost all RhB and P. aeruginosa within 60 min, presenting the strongest photocatalytic activity. The photocatalytic mechanism was investigated based on the radicals trapping and electron spin resonance (ESR) tests together with the first-principle theoretical calculation, validating the dominated roles of ∙OH, ∙O2– and h+ in the photocatalytic reaction. These results provide a new strategy to develop Z-scheme heterojunction photocatalysts with promising utilization prospect in environmental remediation.