A special synthesis of BiOCl photocatalyst for efficient pollutants removal: New insight into the band structure regulation and molecular oxygen activation

Solvothermal modification synthesis of BiOCl could not only affect the structure and band position but also promote activation of molecular oxygen. [Display omitted] •The down-shift of VB and molecular oxygen activation were simultaneously obtained by a special synthesis of BiOCl.•The oxygen vacancy in BiOCl could support the formation of 1O2.•H2O2 could be activated by higher oxidation capability of photogenerated h+ to produce O2−.•These h+, 1O2 andO2− were all responsible for pollutants removal.•Comprehensive investigation of reactive oxygen species was presented. Exploitation of efficient photocatalytic materials is a vital matter to settle the energy and environmental crisis we are facing. In this work, BiOCl with oxygen vacancy (OV-BOC) is synthesized by solvothermal modification method. According to the acquired DRS, VB-XPS, ESR results, solvothermal modification synthesis can not only introduce oxygen vacancy which supports the generation of 1O2 but regulate the band structure, giving rise to the valance band down-shift and hence the photogenerated h+ possesses higher oxidation capacity, which brings about desirable photodegradation efficiency on organic pollutants. It is unexpected that the degradation rate can be promoted by 2.6, 3.1 and 2.4 times after adding a little H2O2 towards rhodamine B, methyl orange and phenol, respectively, which benefits from the increased production of O2−. These increased O2− comes from activated H2O2 through the direct attack of holes which possesses higher oxidation capacity because of valance band down-shift H2O2+h+→•O2-+2H+, as certified by analyses of free radicals and band positions. Radical species capturing and ESR experiments are used to reveal the mechanisms involved by reactive oxygen species and the results show that h+, 1O2 and O2− species are all responsible for photocatalytic degradation. This study may give some guidance on architecting photocatalysts on band structure regulation and molecular oxygen activation simultaneously.