Defect engineering in 0D/2D TiO2/g-C3N4 heterojunction for boosting photocatalytic degradation of tetracycline in a tetracycline/Cu2+combined system

It has been increasingly significant to take advantage of defect engineering in hybrid photocatalysts, aiming to showing novel properties in the remediation of combined pollution such as antibiotic-heavy metal pollution. Herein, a hierarchical 0D/2D TiO2/g-C3N4 heterojunction was fabricated and defects were introduced into the binary-hybrid structure with separate plasma treatment for the each single component. Results show that defect construction on TiO2/CN can exhibit "anisotropic-trapping" effect, where TiO2/D-CN shows stimulation effect while D-TiO2/CN and D-TiO2/D-CN show inhibition on the degradation of tetracycline in the presence of Cu2+. TiO2/D-CN can inhibit the accumulation of Cu2+ and avoid the coverage of active site during the photocatalytic process in contrast to the non-defective or other defective materials. Simultaneously, the formed Cu sites exhibited surface plasmon resonance effect that can enhance the absorption of light, further promoting the photocatalytic degradation of tetracycline. These findings provide new insights into defect construction on binary-heterojunction for the treatment of combined pollution in water.