Highly efficient photocatalytic hydrogen generation of g-C3N4-CdS sheets based on plasmon-enhanced triplet–triplet annihilation upconversion

• Published in: Applied catalysis. B, Environmental Environmental, 2019-12, Vol.258, p.117762, Article 117762
• Main Authors: Fang, Jiaojiao, Chen, Yukai, Wang, Wei, Fang, Liang, Lu, Chunhua, Zhu, Cheng, Kou, Jiahui, Ni, Yaru, Xu, Zhongzi
• Format: Article
• Language: English
• Subjects: Au plasmon resonance; Cadmium; Cadmium sulfide; Carbon nitride; Fossil fuels; Gold; Heterojunctions; Hydrogen; Hydrogen generation; Hydrogen production; Irradiation; Light irradiation; Nanoparticles; Photocatalysis; Photocatalysts; Photons; Platinum; Quantum efficiency; Sheets; Shells; Silica; Silicon dioxide; Triplet-triplet annihilation upconversion; Upconversion
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2019.117762

Scheme Illustrative representation of the photocatalysis mechanism of g-C3N4@CdS based on the Au-enhanced TTA-UCL process. The low-energy green light from solar spectrum can excite the TTA-UC materials, and the addition of Au nanoparticles can further improve the UC efficiency owing to the MPR enhanced absorption of the excitation light. In addition, g-C3N4 was chosen to load with CdS to solve the aggregation and photocorrosion of CdS nanoparticles. Under irradiation, both of CdS and g-C3N4 can produce photogenerated electrons and holes. Because the band structures between CdS and g-C3N4 are well-matched and overlapped, the photogenerated holes of CdS can be captured by g-C3N4. The holes in the valence band of g-C3N4 can oxidize further the sacrificial agent TEA. The photo-induced electrons of g-C3N4 can be transferred effectively to CdS, and the electrons in the valence band of CdS are transfer to the noble metal Pt for proton reduction to hydrogen. More importantly, owing to the bandgap and structure of the heterojunctions g-C3N4@CdS, the increased high-energy photons from Au-enhanced TTA-UC can sensitize effectively g-C3N4@CdS. Under the excitation of Au-enhanced TTA-UC emissions, the activated g-C3N4@CdS can improve separations of electron-hole pairs and thereby enhance significantly hydrogen producing performance. [Display omitted] •The plasmon-based enhancement of TTA-UC process were achieved by introducing first Au into the core liquid of TTA-UC nanoparticles.•After incorporating Au into TTA-UC nanoparticles, the upconverted emission intensity was 2.2-fold higher than the structure without Au.•Compared with OA@SiO2@0.5NC2, Au-enhanced TTA-UC improved the hydrogen production efficiency by about 168% under visible light.•In the presence of Au, the hydrogen production reached the highest value of 0.551 mmol g−1 with the AQY of 1.493% under green light.•This work offers a great strategy to fabricate a plasmon-enhanced TTA-UC-photocatalysis system for stable and efficient hydrogen production. Herein we first coupled a wide photo-response photocatalyst with plasmon-enhanced triplet − triplet annihilation upconversion (TTA-UC) nanoparticles for photocatalytic hydrogen generation. The plasmon-based enhancement of TTA-UC was achieved by introducing Au nanoparticles into the core liquid of TTA-UC nanoparticles containing platinum(II)-octaethylporphyrin and 9,10-diphenylanthracene. Au-TTA nanoparticles encapsulated by silica shells significantly increased the