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).

In-situ synthesis of CdS/g-C3N4 hybrid nanocomposites with enhanced visible photocatalytic activity

“…The broad bands at approximately 3000 cm -1 corresponded to the stretching mode of the terminal NH 2 or NH groups at the defect sites of the aromatic ring [38]. The bands at 1533, 1457, 1129, and 711 cm -1 were attributed to the Cd-S bond [26,29]. The FT-IR spectrum further confirmed the formation of composites that contained the two phases of CdS and g-C 3 N 4 .…”

“…Thus, we report a novel and simple in situ synthetic approach toward CdS/g-C 3 N 4 hybrid nanocomposites, which are based on the growth of CdS nanoparticles and nanorods within the g-C 3 N 4 polymers from metal-containing carbon nitride compounds, similar to the synthesis of Fe-g-C 3 N 4 [28] and ZnO-g-C 3 N 4 [29]. CdS/g-C 3 N 4 hybrid nanocomposites are synthesized using low-cost melamine and Cd(CH 3-COO) 2 Á2H 2 O as precursors to obtain the Cd-g-C 3 N 4 , which are combined through a polycondensation process at elevated temperatures, and combined with sulfur.…”

Can environmental pharmaceuticals be photocatalytically degraded and completely mineralized in water using g-C3N4/TiO2 under visible light irradiation?—Implications of persistent toxic intermediates

“…That is, under visible light irradiation, the g-C 3 N 4 is photoexcited, separating e − and h + in the lowest (LUMO) and highest occupied molecular orbital (HOMO), respectively. The CB of TiO 2 with -0.4 V oxidation potential is more positive than the LUMO of g-C 3 N 4 (−1.12 V); the VB of TiO 2 (+2.8 V) is lower than the HOMO of g-C 3 N 4 (+1.57 V) [54,55]. As such, the e − Fig.…”

Facile Preparation of AgI/Bi2MoO6 Heterostructured Photocatalysts with Enhanced Photocatalytic Activity

“…The strategy facilitates the separation of photogenerated electrons and holes through charge transfer between the semiconductors. [4,5] In recent years, some new heterostructured photocatalysts with high visible-light response have been designed and developed, for example, Bi-based, [6][7][8][9] Ag-based, [10][11][12] and g-C 3 N 4 -based [13][14][15] composite catalysts have attracted great attention. Bi 2 MoO 6 (BMO) is an Aurivilliusphase perovskite oxide that consists of [Bi 2 O 2 ] 2+ layers interleaved by double slabs of MoO 4 2-.…”