title: Fabrication of composite photocatalyst g-C3N4-ZnO and enhancement of photocatalytic activity under visible light.
abstract: The g-C(3)N(4)-ZnO composite photocatalysts with various weight percents of ZnO were synthsized by a simple calcination process. The photocatalysts were characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), UV-vis diffuse reflection spectroscopy (UV-vis), X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA). The PXRD and HR-TEM results show that the composite materials consist of hexagonal wurzite phase ZnO and g-C(3)N(4). The solid-state UV-vis diffuse reflection spectra show that the absorption edge of the composite materials shifts toward the lower energy region and to longer wavelengths in comparison with pure ZnO and g-C(3)N(4). Remarkably, the photocatalytic activity of g-C(3)N(4)-ZnO composites has been demonstrated, via photodegradation of Methyl Orange (MO) and p-nitrophenol experiments. The photocatalytic activity of g-C(3)N(4)-ZnO for photodegradation of Methyl Orange and p-nitrophenol under visible light irradiation was increased by over 3 and 6 times, respectively, to be much higher than that of single-phase g-C(3)N(4), clearly demonstrating a synergistic effect between ZnO and g-C(3)N(4). The concentrations of Zn(2+) in g-C(3)N(4)-ZnO system after a photocatalytic reaction at various reaction times were found to be much lower than those for a ZnO system under the same reaction conditions, indicating that the g-C(3)N(4)-ZnO composite possesses excellent long-term stability for a photocatalytic reaction in aqueous solutions. Furthermore, a synergistic photocatalysis mechanism between ZnO and g-C(3)N(4) was proposed based on the photodegradation results. Such obviously improved performance of g-C(3)N(4)-ZnO can be ascribed mainly to the enhancement of electron-hole separations at the interface of ZnO and g-C(3)N(4).
authors.affiliation: Laboratory of Advanced Porous Materials, and School of Chemistry and Chemical Engineering, Anhui University, Hefei, 230039, China.
authors.forename: Jia-Xin
authors.initials: JX
authors.lastname: Sun
authors.forename: Yu-Peng
authors.initials: YP
authors.lastname: Yuan
authors.forename: Ling-Guang
authors.initials: LG
authors.lastname: Qiu
authors.forename: Xia
authors.initials: X
authors.lastname: Jiang
authors.forename: An-Jian
authors.initials: AJ
authors.lastname: Xie
authors.forename: Yu-Hua
authors.initials: YH
authors.lastname: Shen
authors.forename: Jun-Fa
authors.initials: JF
authors.lastname: Zhu