Carbon-modified photocatalyst has attracted extensive attentions in the field of gaseous pollutant removal, mainly due to the improved adsorption properties and electronic transport of carbon matrix, such as carbon nanotubes, graphene, and fullerene, etc. In this work, carbon quantum dots (CQDs) were employed to enhance the photocatalytic performance of TiO 2 -based composites for flowing gaseous acetaldehyde removal. Besides the aforementioned advantages of carbon materials, the unique up-converted photoluminescence property of CQDs is capable of extending the optical absorption to visible-light range. Moreover, the electron spin resonance (ESR) results firstly verified a stable existence of Ti 3+ defect in the CQDs/TiO 2 composite, which is possibly induced by the electron migration from CQDs to TiO 2 . And the formed Ti 3+ donor energy level in the band gap could further help with the visible-light harvesting. During the photodegradation experiments, with two-hour continuous flowing gaseous acetaldehyde injection (500 ppm, 20 sccm), the CQDs/TiO 2 composite remained 99% removal efficiency under fluorescent lamp irradiation (λ > 380 nm). The optimized CQDs content was obtained as 3 wt%, and the underlying mechanism was further analyzed by temperature programmed desorption (TPD) methods. This work will push forward the air purification researches by providing new insights of CQDs sensitized photocatalyst.
Bibliographical noteFunding Information:
This work was financially supported by the National Key Research and Development Program of China ( 2016YFA0203000 ), the International Partnership Program of Chinese Academy of Sciences ( GJHZ1656 ), and the National Natural Science Foundation of China (No. 51702347 ).
© 2018 Elsevier B.V.
- Acetaldehyde removal
- Carbon quantum dots