One-pot preparation of novel Bi/BiOBr/Bi2O2CO3 heterojunction for pollutant degradation under visible light: Catalyst generation insights, reaction mechanism, degradation pathways, and toxicological effects

Bi/BiOBr/Bi2O2CO3 heterojunction was synthesized by one-pot hydrothermal method using DMF as carbon source for Bi2O2CO3 and reducing agent for Bi3+, NaBr as bromine source and Bi(NO3)3 as bismuth source. The photocatalytic properties were evaluated with photodegradation of rhodamine B, tetracycline and oxytetracycline under visible light with the degradation efficiency of 99.83% (k = 0.5843 min−1, 9 min), 81.75% (k = 0.0247 min−1, 60 min) and 70.23% (k = 0.0225 min−1, 60 min), respectively. The enhanced photoactivity is ascribed to the increased separation efficiency of photogenerated electron-hole pair and improved electron migration rate, causing by strong visible-light adsorption, surface plasmon resonance of Bi nanoparticles and the matched energy band between BiOBr and Bi2O2CO3. In addition, as nitrogen-containing organic pollutants of rhodamine B, tetracycline and oxytetracycline, N element was proved to form ammonium under photocatalysis with indoxyl blue method. More importantly, this work also evaluated the ecotoxicological effects of pollutant, indicating the decreased ecotoxicological effects of pollutant after degradation.