Enhanced visible-light properties of TiO2/diatomite composite over varied bismuth semiconductors modification for formaldehyde photodegradation: A comparative study

How to improve the photocatalytic performance of titania-based photocatalyst under visible light in environmental remediation remains a challenge. Herein, three kinds of bismuth semiconductors, including Bi2MoO6, BiOCl and BiVO4, are selected to construct heterojunctions with diatomite supporting titania for improving photocatalytic performance towards formaldehyde (HCHO) under visible light. The morphologies and microstructures as well as the photocatalytic performance of the as-received samples are systematically investigated for comparation. The Bi2MoO6-TiO2/diatomite (MTD-50) composite has the optimal performance, followed by BiOCl-TiO2/diatomite (CTD-100) composite and BiVO4-TiO2/diatomite (VTD-75) composite, whose mineralization rate is up to around 47.58 times, 29.55 times and 21.14 times that of TiO2/diatomite (TD) composite, respectively. Moreover, the performance enhancement mechanism could be attributed to their relatively high quantum efficiency that originated from the heterojunctions, resulting in the high generation efficiency of active radicals. This work would like to compare bismuth semiconductor photocatalysts for enhancing visible-light properties through heterojunction and provide comparative references for developing novel visible light driven photocatalysts in the field of indoor HCHO purification.

Automated summary

In this study, three types of bismuth semiconductors were selected to construct heterojunctions with titania supported on diatomite for improving photocatalytic performance under visible light. The Bi2MoO6-TiO2/diatomite composite showed the highest performance, with a mineralization rate of 47.58 times that of the TiO2/diatomite composite. The performance enhancement mechanism was attributed to the relatively high quantum efficiency of the heterojunctions, resulting in a higher generation efficiency of active radicals.