title: Earth-abundant NiS co-catalyst modified metal-free mpg-C3N4/CNT nanocomposites for highly efficient visible-light photocatalytic H2 evolution.
abstract: In the present work, the earth-abundant NiS co-catalyst modified mesoporous graphite-like C3N4 (mpg-C3N4)/CNT nanocomposites were prepared via a two-step strategy: the sol-gel method and the direct precipitation process. The mpg-C3N4/CNT/NiS composite photocatalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV-vis absorption spectroscopy, photoluminescence spectroscopy (PL), photoelectrochemical (PEC) and electrochemical impedance spectra (EIS) experiments. The photocatalytic H2-production activity over the composite catalysts was also evaluated by using an aqueous solution containing triethanolamine under visible light (λ≥ 420 nm). The results showed that the loading of earth-abundant NiS co-catalysts onto metal-free mpg-C3N4/CNT nanocomposites can remarkably enhance their photocatalytic H2-production activity. The optimal loading amount of NiS on metal-free mpg-C3N4/CNT nanocomposites was about 1 wt%. The as-obtained mpg-C3N4/CNT/1% NiS ternary composite photocatalyst exhibits the best H2-evolution activity with the highest rate of about 521 μmol g(-1) h(-1) under visible light (λ≥ 420 nm), which is almost 148 times that of a pure mpg-C3N4/CNT sample. The enhanced photocatalytic activity can be mainly attributed to the synergistic effect of effectively promoted separation of photo-generated electron-hole pairs and enhanced H2-evolution kinetics. The co-loading of nanocarbon materials and earth-abundant co-catalysts onto metal-free mpg-C3N4 photocatalysts offers great potential for practical applications in photocatalytic H2 evolution under visible light illumination.
authors.affiliation: College of Materials and Energy, South China Agricultural University, Guangzhou 510642, P. R. China. Xinliscau@yahoo.com wlscau@163.com ypfang@scau.edu.cn.
authors.forename: Yongming
authors.initials: Y
authors.lastname: Zhong
authors.forename: Jielin
authors.initials: J
authors.lastname: Yuan
authors.forename: Jiuqing
authors.initials: J
authors.lastname: Wen
authors.forename: Xin
authors.initials: X
authors.lastname: Li
authors.forename: Yuehua
authors.initials: Y
authors.lastname: Xu
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.forename: Shengsen
authors.initials: S
authors.lastname: Zhang
authors.forename: Yueping
authors.initials: Y
authors.lastname: Fang
mesh_terms: D002384:Catalysis; D006108:Graphite / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry*; D008027:Light; D008958:Models, Molecular; D053761:Nanocomposites / Q000737:chemistry* / Q000648:ultrastructure; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure; D009532:Nickel / Q000737:chemistry*; D055668:Photochemical Processes; D056951:Photoelectron Spectroscopy; D016062:Porosity; D014961:X-Ray Diffraction
chemical_list: D037742:Nanotubes, Carbon; D006108:Graphite; D009532:Nickel; D006859:Hydrogen; C017558:nickel sulfide