Heterogeneous photocatalysis has long been considered to be one of the most promising approaches to tackling the myriad environmental issues. However, there are still many challenges for designing efficient and cost-effective photocatalysts and photocatalytic degradation systems for application in practical environmental remediation. In this review, we first systematically introduced the fundamental principles on the photocatalytic pollutant degradation. Then, the important considerations in the design of photocatalytic degradation systems are carefully addressed, including charge carrier dynamics, catalytic selectivity, photocatalyst stability, pollutant adsorption and photodegradation kinetics. Especially, the underlying mechanisms are thoroughly reviewed, including investigation of oxygen reduction properties and identification of reactive oxygen species and key intermediates. This review in environmental photocatalysis may inspire exciting new directions and methods for designing, fabricating and evaluating photocatalytic degradation systems for better environmental remediation and possibly other relevant fields, such as photocatalytic disinfection, water oxidation, and selective organic transformations.
• Bi doping in TiO2 enhanced the separation of photo-generated electron-hole.• The performance of photocatalytic degradation of MC-LR was improved.• Coexisting substances have no influence on algal removal performance.• The key reactive oxygen species were h+ and •OH in the photocatalytic process. The increase in occurrence and severity of cyanobacteria blooms is causing increasing concern; moreover, human and animal health is affected by the toxic effects of Microcystin-LR released into the water. In this paper, a floating photocatalyst for the photocatalytic inactivation of the harmful algae Microcystis aeruginosa (M. aeruginosa) was prepared using a simple sol-gel method, i.e., coating g-C3N4 coupled with Bi-doped TiO2 on Al2O3-modified expanded perlite (CBTA for short). The impact of different molar ratios of Bi/Ti on CBTA was considered. The results indicated that Bi doping in TiO2 inhibited photogenerated electron-hole pair recombination. With 6 h of visible light illumination, 75.9% of M. aeruginosa (initial concentration= 2.7 × 106 cells/L) and 83.7% of Microcystin-LR (initial concentration= 100 μg/L) could be removed with the addition of 2 g/L CBTA-1% (i.e., Bi/Ti molar ratio= 1%). The key reactive oxygen species (ROSs) in the photocatalytic inactivation process are h+ and •OH. The induction of the Bi4+/Bi3+ species by the incorporation of Bi could narrow the bandgap of TiO2, trap electrons, and enhance the stability of CBTA-1% in the solutions with coexisting environmental substances. 相似文献