In-depth insight into the mechanism on photocatalytic selective CO2 reduction coupled with tetracycline oxidation over BiO1-xBr/g-C3N4

To effectively alleviate environmental pollution and energy shortage and simultaneously utilize the photo -induced electrons and holes in one system. Herein, a dual-purpose reaction system is structured by coupling CO2 reduction with tetracycline (TC) mineralization, which is realized using model BiOBr/g-C3N4 photocatalyst with rich oxygen vacancies (OVs) (donated as BiO1-xBr/g-C3N4). Compared to two half-reactions of the indi-vidual CO2 photoreduction and independent TC oxidation under Ar atmosphere, such designed coupled reaction system presents much superior catalytic performance than those of two half-reactions. Another crucial finding is that the concentration and molecular structure of TC directly affect the selectivity and synergistic efficiency of photocatalytic CO2 reduction to CO. The mechanism of cooperative effect is discussed deeply according to theoretical calculation and experiments. Besides, the intermediates and pathway of TC degradation are extremely inquired by LC-MS. The work is expected to provide beneficial guidance on reasonably devising the bifunctional catalysts with efficacious integrating reaction systems for coupling CO2 reduction with antibiotic removal.