Ni-doped β-Bi2O3 microspheres cooperated with amorphous carbon nitride (ACN) with three coordinate nitrogen vacancies to construct heterojunction for enhanced pollutants degradation and photocatalytic H2 production

Abstract

In this study, a novel S-scheme Ni-doped β-Bi2O3/ACN heterojunction with superior enhanced photoactivity was successfully prepared via two-step methods. The degradation efficiency of target pollutant ciprofloxacin (CIP) by the 7%Ni-doped β-Bi2O3/3%ACN composite (3A@BN7) within 1 ​h is as high as 95.93%, which is 5.54 times than β-Bi2O3 and 2.83 times than ACN. Moreover, the heterojunction composites synthesized in this work exhibited extraordinary removal effects on various pollutants. Meanwhile, the 3A@BN7 composites possess the ability to evolution hydrogen under visible-light irradiation with an efficiency reached 3099.1 ​μmol H2 within 4 ​h, while the pure β-Bi2O3 does not show any hydrogen evolution capability. The characterization results manifest that the enhancement of the photocatalytic activity of the heterojunction composites is attributed to more abundant reactive sites, higher utilization rate of visible light, lower interfacial charge transfer resistance than pure β-Bi2O3. Staggered energy level structure of the composites cooperating with Ni doping led to lower recombination rate of hole-electron pairs and narrower band-gap are also reflected in improved photoactivity. A possible mechanism of the S-scheme heterojunction for the enhancing photocatalytic activity is proposed combined with the results of all characterization and experiments. This work puts forward a novel heterostructure constructing method for β-Bi2O3, which may provide a reference for application in industrial removal of organic pollution from water due to its excellent stability and wide selectivity.