Ti3C2 Mxene/porous g-C3N4 interfacial Schottky junction for boosting spatial charge separation in photocatalytic H2O2 production

• Published in: Applied catalysis. B, Environmental Environmental, 2019-12, Vol.258, p.117956, Article 117956
• Main Authors: Yang, Yang, Zeng, Zhuotong, Zeng, Guangming, Huang, Danlian, Xiao, Rong, Zhang, Chen, Zhou, Chengyun, Xiong, Weiping, Wang, Wenjun, Cheng, Min, Xue, Wenjing, Guo, Hai, Tang, Xiang, He, Donghui
• Format: Article
• Language: English
• Subjects: Carbon nitride; Chemical energy; Electric fields; Energy conversion; Hydrogen peroxide; Hydrogen production; Irradiation; Light irradiation; MXenes; Nanostructure; Organic chemistry; Oxygen; Photocatalysis; Photocatalytic H2O2 production; Porous g-C3N4; Radiation; Recombination; Rotating disks; Schottky junction; Self-assembly; Separation; Single electrons; Solar energy; Spatial charge separation; Superoxide; Ti3C2 Mxene
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2019.117956

[Display omitted] •A unique interfacial Schottky junction composed of Ti3C2 nanosheets and porous g-C3N4 nanosheets (TC/pCN) was constructed.•Accelerated spatial charge separation and transfer on TC/pCN interfacial Schottky junction.•Excellent ability for photocatalytic H2O2 production under visible light irradiation.•Route of the photocatalytic H2O2 production and mechanism of the improved photocatalytic performance were proposed. The development of efficient photocatalysts for the production of hydrogen peroxide (H2O2) is a promising strategy to realize solar-to-chemical energy conversion. Graphitic carbon nitride (g-C3N4) presents giant potential for photocatalytic H2O2 production, but the sluggish charge separation depresses its photocatalytic performance. Herein, an interfacial Schottky junction composed of Ti3C2 nanosheets and porous g-C3N4 nanosheets (TC/pCN) is constructed by a facile electrostatic self-assembly route to significantly boost the spatial charge separation to promote the activation of molecular oxygen for H2O2 production. As the optimal sample, TC/pCN-2 possesses the highest H2O2 production rate (2.20 μmol L−1 min−1) under visible light irradiation (λ > 420 nm), which is about 2.1 times than that of the porous g-C3N4. The results of superoxide radical detection and rotating disk electrode measurement suggest that the two-step single-electron reduction of oxygen is the predominant reaction step during this photocatalytic H2O2 production process. The enhanced photocatalytic performance is ascribed to the formation of Schottky junction and subsequent built-in electric field at their interface, which accelerate the spatial charge separation and restrain the charge recombination. This work provides an in-depth understanding of the mechanism of photocatalytic H2O2 production, and gives ideas for the design of highly active materials for photocatalytic H2O2 production.