Assembling an S-type heterojunction comprising vacancy-rich CeO2-x and CuBi2O4 for improved photocatalytic oxidation of gaseous toluene

Abstract

The exploration of highly efficient methods for degrading VOCs, with concurrent low energy consumption and lasting reusability, holds significant appeal. In this regard, an S-type CuBi2O4/CeO2-x heterojunction with the robust interfacial interactions is presented as an active photocatalyst for the efficient decomposition of gaseous toluene under full-spectrum irradiation. The optimal sample CC15 effectively degrades gaseous toluene at a high concentration of 1800 ppm within 2 h, achieving a notable CO2 yield of 87.05 %, and a TOC (total organic carbon) removal rate of 89.33 %. Furthermore, CuBi2O4/CeO2-x exhibits exceptional stability, maintaining its 100 % degradation capability over 32 cycles for nearly 64 h. Comparative characterization reveals that the superior performance derives from an abundance of oxygen vacancies and effective pre-adsorption capabilities, which facilitate rapid adsorption of VOCs on the catalyst surface, thereby increasing the likelihood of degradation reactions. Additionally, the formation of an S-type heterojunction, valence pairing between Bi3+ and Ce3+/4+ ions, and strong interfacial interactions serve as the primary pathways for the efficient separation of photogenerated carriers, contributing to the high CO2 production rate and prolonged cycle stability. The present investigation underscores the significant potential of vacancy-rich S-type heterojunctions and interfacial interactions between composite components, offering excellent activity and long-term availability for VOCs removal.