The enhanced photocatalytic activity of Ag-OVs-(0 0 1) BiOCl by separating secondary excitons under double SPR effects

[Display omitted] •The “hot electrons” of oxygen vacancies attracted Ag+ and reduced Ag+ to Ag.•Under light, high-energy electrons of Ag were propagated to BiOCl by TSPR.•The electrons and holes released from excitons were accelerated to separate by Ag. The Ag-OVs-(0 0 1) BiOCl photocatalysts were synthesized by photodeposition method. The strong singlet oxygen signal meant that BiOCl only produce very few free electrons and not enough to reduce Ag+ to Ag. Inevitably, the “hot electrons” of oxygen vacancies reduced Ag+ and Ag occupied oxygen vacancies of BiOCl. Under light, high-energy electrons of Ag were propagated to BiOCl by propagating surface plasmon resonance (TSPR), and the high-energy electrons scrambled for the holes of primary excitons in BiOCl to form secondary excitons. The electrons in the primary excitons were released, while the secondary excitons were captured by oxygen vacancies and the holes of secondary excitons were released. The electrons released from primary excitons and the holes released from secondary excitons were accelerated to separate under the local electric field (LSPR) effect of Ag, and lots of superoxide radicals and holes participated in the catalytic reaction. The photocatalytic activity of Ag-OVs-(0 0 1) BiOCl was improved under the polarization charges, TSPR and LSPR effects of Ag, and the degradation rate of RhB by Ag-OVs-(0 0 1) BiOCl was 2.64 times that of BiOCl under the simulated sunlight.