Needle growth of Nb2O5 nanoparticles on BiOCl nanosheets to fabricate S-scheme heterojunction with oxygen vacancies for enhanced photooxidation of cyclohexane

The exploration of cost-efficient, environmentally friendly, and high-efficacy photocatalysts for the enhanced selective photooxidation of cyclohexane to KA oil (cyclohexanone (CHA-one) and cyclohexanol (CHA-ol)) is a pivotal challenge in the industrial realm. Herein, the present study focuses on the synthesis of needle-like S-scheme heterojunction photocatalysts with oxygen vacancies, which are achieved by the needle growth integration of nano-sized Nb 2 O 5 particles onto the BiOCl nanosheets. Remarkably, the 40 % Nb 2 O 5 /BiOCl composites exhibited superior performance in the solvent-free photooxidation of cyclohexane at room-temperature and under atmospheric pressure. The production yield of KA oil was 180.3 μmol (CHA-one/CHA-ol molar ratio = 3.5), and exceptional selectivity towards KA oil, reaching up to 99.3 %. The enhanced photocatalytic efficiency in cyclohexane oxidation can be attributed to the unique S-scheme heterogeneous interfaces with specific nanoneedle morphology, which result in the enhanced photonic absorption, effective charge carrier separation, a high density of oxygen vacancies, and the exposure of the highly reactive (001) plane of BiOCl. The excellent interfacial charge separation and transfer pathways of S-scheme heterojunction are disclosed by the in-depth EPR analysis and DFT calculations. These insights highlight the significant potential of the needle-like Bi-based S-scheme heterojunction photocatalysts for the efficient photooxidation of saturated alkanes.