Design and construction of clinoptilolite-decorated BiOBr-TiO2 heterojunction as efficient and affordable photocatalyst for herbicide contaminated wastewater splitting

In this study, the insightful photocatalytic properties and efficiency of TiO₂-BiOBr heterojunctions embedded within clinoptilolite matrix for the simultaneous H₂ generation and bentazon-polluted water treatment were assessed. The characterization outcomes indicated that immobilizing TiO₂-BiOBr heterojunction has the potential to enhance dispersion and arrangement of photoactive components, while mitigating the recombination rate of heterostructure. These characteristics become increasingly prominent as the TiO₂/BiOBr weight ratio in the embedded heterogeneous structure rises. This betterment can be originated from the enhancement in the interaction of TiO₂ with BiOBr species which elevates likely of creating stronger TiO₂-BiOBr heterojunction and inhibits the creation of defects sites and the growth of bismuth-based nanosheets. Moreover, raising the content of immobilized TiO₂-rich heterojunction (TiO₂/BiOBr weight ratio of 3/1) from 0 to 40 wt.% elevated the elimination efficiency while it declined upon further increasing the immobilization content. Although specific surface area increases, overloading of TiO₂-BiOBr heterojunction as a result of the formation of more surface agglomerates causes a significant diminution in the number of accessible photoactive sites and inappropriate interaction between clinoptilolite and TiO₂-BiOBr heterojunction which restrict the absorb light and lifetime of electron-hole pairs, respectively. In accordance with characterization results, it was found that embedding 40 wt.% TiO₂-rich heterojunction within zeolite matrix endows the best photocatalytic activity towards bentazon elimination. The experimental findings also demonstrate the high effectiveness of this sample in the concurrent photocatalytic processes of hydrogen production and bentazon-contaminated wastewater treatment. Under irradiation of UV and simulated solar lights, the hydrogen generation rate of 3731 μmol.g^-1.h^-1 along with the complete elimination of bentazon and the rate of hydrogen generation of 2853 μmol.g^-1.h^-1 with a removal efficiency of 81% were attained, respectively.