Rational design of multifunctional C/N-doped ZnO/Bi2WO6 Z-scheme heterojunction for efficient photocatalytic degradation of antibiotics

A multifunctional C/N-ZnO/Bi 2 WO 6 Z-scheme heterojunction was fabricated by ZIF-8 derived C/N-ZnO and Bi 2 WO 6 for improving the visible light absorption performance and accelerating the carriers transfer due to the doping of C/N and addition of residual C species. • C/N-doped ZnO with residual C species was developed by regulated pyrolysis of ZIF-8. • The bandgap of ZnO was regulated by doping C/N. • Coordination adsorption between Zn 2+ and antibiotic accelerate removal of pollutants. • Constructing a Z-scheme heterojunction by residual C as an electron transfer medium. A multifunctional Z-scheme C/N-ZnO/Bi 2 WO 6 (CZB) photocatalyst was fabricated by ZIF-8 derived C/N-ZnO and Bi 2 WO 6 via a regulated pyrolysis. The obtained photocatalysts were characterized and the photocatalytic activity was investigated by degrading antibiotics. Especially, the composite with 5% mass ratio of C/N-ZnO (5-CZB) exhibited the best photocatalytic activity for tetracycline, enrofloxacin and norfloxacin under visible light irradiation and degradation efficiency was 4.48, 2.43 and 2.79 times higher than pure Bi 2 WO 6 , respectively. That was mainly due to the doping of C/N in ZnO structure from the pyrolysis of ZIF-8 regulated the band gap and improved the photoresponse ability. Meanwhile, the residual C species as an electron transfer medium were conducive to constructing Z-scheme heterojunction between ZnO and Bi 2 WO 6 . The synergistic effect leaded to the extension of light response range and acceleration of the carriers transfer. The tests showed that •O 2 – and h + were the dominant active species to decomposed antibiotic molecules. Additionally, coordination adsorption between Zn 2+ in CZB composites and antibiotic molecules is beneficial to removal the pollutants, which provides an interesting approach for designing photocatalysts.