Boron doping enhance built-in electric fields in g-C3N4/TiO2 for efficient norfloxacin degradation

The addition of B enhances the built-in electric field in the heterojunction. • The heterojunction could effectively degrade NOR over different environmental parameters. • The possible photocatalytic degradation pathway of NOR was investigated. • S-scheme charge transfer mechanism in heterojunction was proposed Antibiotic residues in natural water have posed great risks to ecological safety and public health. There, B-doped g-C 3 N 4 /TiO 2 (BCN/TNS) S-scheme heterojunctions were constructed through self-deposition. The optimized 0.7BCN/TNS heterojunction exhibited superior photocatalytic activity and degraded 94.8% norfloxacin (NOR) within 90 min, the rate constant was 2.06-fold and 1.46 folds than that of TiO 2 nanosheet array (TNS) and g-C 3 N 4 /TiO 2 (CN/TNS). The as-prepared also displayed high stability and strong adaptability over different environmental parameters. Radical trapping experiments and ESR measurements verified that ·O 2 - was the dominant active species during NOR degradation. Photoelectrochemical measurements and theoretical calculations indicate that the introduction of B not only increases the number of active sites and broadens the spectral absorption range, but also enhances the strength of the internal electric field (IEF), promoting charge transfer at the heterointerface. This paper supports a feasible strategy for designing a superior B-doped g-C 3 N 4 -based heterojunction for antibiotic wastewater treatment. Download: Download high-res image (192KB) Download: Download full-size image B-doped g-C 3 N 4 /TiO 2 S-scheme heterojunctions for efficient norfloxacin removal.