Efficient photocatalytic simultaneous removal of organic and heavy metal complex pollutants under visible light by crystal-facet-mediated TiO2/Ti3C2-BiOBr nanocomposites

Developing regularly active facet-mediated catalysts remains an ongoing challenge to address rapid recombination and slow transfer of electron-hole pairs during photocatalytic removal of pollutants from water. Herein, crystal-facet-mediated TiO2/Ti3C2-BiOBr nanocomposites have been successfully fabricated by in situ growing active (001) facets exposed TiO2 nanosheets on highly conductive Ti3C2Tx MXene and then growing BiOBr with exposed facets ((102), (110) and (001)) on (001)TiO2/Ti3C2. The (001)TiO2/Ti3C2-BiOBr heterojunctions displayed remarkable enhancement in photocatalytic simultaneous removal of rhodamine B (RhB) and hexavalent chromium (Cr(VI)) complex pollutants under visible light. TB(102) that highly exposed (102) facets of BiOBr exhibited the best photocatalytic activities with the removal rates of RhB and Cr(VI) reaching 0.378 and 0.039 min-1, respectively, which also achieved 100 % RhB degradation and 69.7 % Cr(VI) reduction within 60 min under sunlight. The mechanism of photocatalytic process was unearthed based on experiment results and various characterizations. This study provides significant reference for improving the activity of photocatalyst through multiple strategies.