Wei Congcong,Zhang Wei,Wang Xinpeng,Li Aihong,Guo Jianping,Liu Bo
Abstract Here, g-C 3 N 4 /TiO 2 photocatalysts with mesoporous structure and intimate interfacial connection were synthesized via the facile pyrolysis of g-C 3 N 4 /MIL-125 composites. The photocatalytic H 2 evolution reaction was performed to examine the photocatalytic activity of obtained photocatalysts. Under the UV–vis light irradiation, the average H 2 evolution rate of g-C 3 N 4 /TiO 2 sample with optimal g-C 3 N 4 loading content (4.12wt%) was most increased by up to 0.606 mmol·g −1 ·h −1 , a value which transcended that of as-prepared g-C 3 N 4 (0.138 mmol·g −1 ·h −1 ) and mesoporous TiO 2 (0.244 mmol·g −1 ·h −1 ) by a factor of 4.41 and 2.48, respectively. The improvement in photocatalytic activity of g-C 3 N 4 /TiO 2 composites was explained by the synergistic effect between large specific surface area, decreased energy band gap and intimate interface contact. This study demonstrated a new approach for the preparation of binary mesoporous heterojunction photocatalysts. Graphical Abstract
Shangyuan Ni,Zhengrong Fu,Lin Li,Manying Ma,Yuelin Liu
Construction of heterojunction between semiconductors is considered an effective strategy for enhancing photocatalytic capability. Herein, this work prepared an abundant porous g-C 3 N 4 /TiO 2 photocatalyst , with the two-dimensional (2D) nanosheet g-C 3 N 4 and nanoparticle TiO 2 . The heterojunction both enhanced the ultraviolet (UV) light absorption ability, and inhibited the recombination of photogenerated electron-hole (h + ) pairs. As expected, the optimal 4 % g-C 3 N 4 /TiO 2 (g-C 3 N 4 :TiO 2 = 1:25) exhibited a prominent degradation efficiency of 96.53 % in the photocatalytic performance of tetracycline hydrochloride (TCH) under UV irradiation . The recycling of the heterojunction photocatalyst g-C 3 N 4 /TiO 2 remained stability and reusability. The main active species were·O 2- , h + and·OH, and the formation of internal electric field on the step-scheme (S-scheme) heterojunction interface accelerated the migration of photogenerated carriers. Moreover, several environmental factors on degradation such as dose, pH, and the initial concentration of TCH were investigated. This work could be spread to the conceive of other S-scheme heterojunction photocatalysts in application to different environmental demands.
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