Chinese Journal of Catalysis ›› 2017, Vol. 38 ›› Issue (2): 240-252.DOI: 10.1016/S1872-2067(17)62759-1

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Enhanced visible light photocatalytic H2 production over Z-scheme g-C3N4 nansheets/WO3 nanorods nanocomposites loaded with Ni(OH)x cocatalysts

Kelin Hea,b,c, Jun Xiea,b,c, Xingyi Luoa,c, Jiuqing Wena,b,c, Song Maa,b,c, Xin Lia,b,c, Yueping Fanga, Xiangchao Zhangd   

  1. a College of Materials and Energy, Guangzhou 510642, Guangdong, China;
    b College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, Guangdong, China;
    c Key Laboratory of Energy Plants Resource and Utilization, Ministry of Agriculture, Key Laboratory of Biomass Energy of Guangdong Regular Higher Education Institutions, Institute of New Energy and New Materials, South China Agricultural University, Guangzhou 510642, Guangdong, China;
    d Hunan Key Laboratory of Applied Environmental Photocatalysis, Changsha University, Changsha 410022, Hunan, China
  • Received:2016-10-30 Revised:2016-11-20 Online:2017-02-18 Published:2017-03-14
  • Contact: 10.1016/S1872-2067(17)62759-1
  • Supported by:

    This work was supported by the National Natural Science Foundation of China (51672089), the Industry and Research Collaborative Innovation Major Projects of Guangzhou (201508020098), the State Key Laboratory of Advanced Technology for Material Synthesis and Processing (Wuhan University of Technology) (2015-KF-7) and the Hunan Key Laboratory of Applied Environmental Photocatalysis (Changsha University) (CCSU-XT-04).

Abstract:

Novel WO3/g-C3N4/Ni(OH)x hybrids have been successfully synthesized by a two-step strategy of high temperature calcination and in situ photodeposition. Their photocatalytic performance was investigated using TEOA as a hole scavenger under visible light irradiation. The loading of WO3 and Ni(OH)x cocatalysts boosted the photocatalytic H2 evolution efficiency of g-C3N4. WO3/g-C3N4/Ni(OH)x with 20 wt% defective WO3 and 4.8 wt% Ni(OH)x showed the highest hydrogen production rate of 576 μmol/(g·h), which was 5.7, 10.8 and 230 times higher than those of g-C3N4/4.8 wt% Ni(OH)x, 20 wt% WO3/C3N4 and g-C3N4 photocatalysts, respectively. The remarkably enhanced H2 evolution performance was ascribed to the combination effects of the Z-scheme heterojunction (WO3/g-C3N4) and loaded cocatalysts (Ni(OH)x), which effectively inhibited the recombination of the photoexcited electron-hole pairs of g-C3N4 and improved both H2 evolution and TEOA oxidation kinetics. The electron spin resonance spectra of ·O2- and ·OH radicals provided evidence for the Z-scheme charge separation mechanism. The loading of easily available Ni(OH)x cocatalysts on the Z-scheme WO3/g-C3N4 nanocomposites provided insights into constructing a robust multi-ple-heterojunction material for photocatalytic applications.

Key words: Photocatalytic hydrogen evolution, Robust Ni(OH)x cocatalyst, g-C3N4, Z-Scheme systems, Heterojunction