Pd nanoclusters/TiO2(B) nanosheets with surface defects toward rapid photocatalytic dehalogenation of polyhalogenated biphenyls under visible light

Constructing effective photocatalysts with visible light response to achieve rapid dehalogenation of polyhalogenated compounds remains a challenge nowadays. Herein, Pd nanoclusters-decorated TiO2 nanosheets with surface defects (Pd/TNS) are designed for polyhalogenated biphenyls dehalogenation under visible light. Pd/TNS is able to rapidly remove bromine atoms of 4-bromobiphenyl in 30 min. Experimental results reveal that oxygen vacancies and Ti3+ are in-situ generated in TNS during Pd photodeposition, which extend the absorption band edge of Pd/TNS to visible light region. Besides, the unique two-dimensional nanosheets structure of TNS contributes to a high surface area for high dispersion of Pd nanoclusters. Importantly, the Pd nanoclusters serve to activate carbon-halogen bond in polyhalogenated biphenyls and hydrogen-oxygen in H2O. The high dehalogenation efficiency could be assigned to a strong chemical interaction and synergistic effect between the Pd nanoclusters and TiO2(B) nanosheets. Finally, a collaborative mechanism is proposed for photocatalytic dehalogenation of polyhalogenated biphenyls on Pd/TNS.