Superior visible light photocatalytic activity of g-C3N4/NiWO4 direct Z system for degradation of gaseous toluene

• Published in: Journal of solid state chemistry 2019-04, Vol.272, p.62-68
• Main Authors: Dao, Van-Duong, Son, Le Thanh, Nguyen, Trinh Duy, Van Noi, Nguyen, Ngoc, Nguyen Minh, Pham, Thanh-Dong, Van Quan, Pham, Trang, Hoang Thu
• Format: Article
• Language: English
• Subjects: g-C3N4; NiWO4; Photocatalyst; Toluene removal; Z direct scheme
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1016/j.jssc.2019.01.030

In this study, we combined g-C3N4 and NiWO4 to establish g-C3N4/NiWO4 composites for removal of gaseous toluene. The obtained characterization and toluene removal results indicated that the photocatalytic activities of the established g-C3N4/NiWO4 were much higher than that of the single component. A direct Z scheme mechanism is proposed for the enhancement. Because of the intimate integration between g-C3N4 and NiWO4, the photo-excited electrons in the conduction band of the NiWO4 tends to combine with photo-excited holes in the valence band of the g-C3N4 preserving the existence of electrons in the conduction band of the g-C3N4 and holes in the valence band of the NiWO4. Therefore, the established g-C3N4/NiWO4 system could produce significant amounts of available electrons and holes for photocatalytic degradation of toluene even under visible light. Among established g-C3N4/NiWO4 materials, the 1C/1N material, which the mole ratio of g-C3N4 was equal to that of NiWO4, exhibited the highest photocatalytic degradation of toluene. The maximum removal efficiency and mineralization degree of toluene by 1C/1N were 95.3% and 99.1%, respectively. We also investigated that the prepared g-C3N4/NiWO4 materials exhibited high stability during long-term toluene removal. Photocatalytic mechanism of g-C3N4/NiWO4 for degradation of gaseous toluene under visible light [Display omitted] •g-C3N4/NiWO4 Z direct scheme system were successfully established.•Z-scheme prevented fast recombination of e- and h+ and remained their oxidative ability.•The established materials exhibited excellent photocatalytic degradation of gaseous toluene.•The optimal mole ratio of g-C3N4/(NiWO4 + g-C3N4) for toluene removal was 50%.•The 1C/1N removed 95.3% toluene and mineralized 99.1% of them into CO2 and H2O.