Chuansheng Chen

Enhanced photocatalytic properties of graphene oxide/ZnO nanohybrid by Mg dopants

In this study, the enhancement of photocatalytic activity of a graphene oxide/ZnO (GO/ZnO) nanohybrid was achieved via introducing Mg as a co-dopant element by the co-precipitation method. The Mg-doped ZnO nanoparticles were adsorbed on GO sheets. Compared with the catalyses with GO/ZnO nanohybrids, GO/Zn1−xMgxO nanohybrids exhibited better photocatalytic activity, in which the decomposition rate of methyl orange (MO) reached 100% within 60 min. The enhancement is attributed to Mg-doping and efficient charge transfer of the photogenerated electrons in the conduction band of ZnO to graphene.

ARCHITECTURE OF FLOWER-LIKE rGO/CNTs-LOADED CuxO NANOPARTICLES AND ITS PHOTOCATALYTIC PROPERTIES

Novel flower-like composite architecture was successfully synthesized by spray drying and post-calcinating method for the first time. Scanning electron microscopy and transmission electron microscopy observations confirmed that reduced graphene oxides/carbon nanotubes hybrid (rGO/CNTs) formed a flower-like micrometer structure and Cu2O, CuO (CuxO, x = 1 or 2) nanoparticles were decorated inside them. The photocatalytic properties were further investigated by evaluating the photodegradation of a pollutant methyl orange (MO). The experimental results indicated that this novel architecture enhanced photocatalytic performance with 96.2% decomposition of MO after 25 min in the presence of H2O2 under visible light irradiation, which was much higher than that of CuxO powders (33.2%). This could be attributed to the more efficient adsorption of MO molecules on flower-like rGO/CNTs and provide a high concentration of MO near to the CuxO nanoparticles, thus promoting the photocatalytic degradation process.

Graphene Supported Small-sized ZnO Nanoparticles and Their Photocatalytic Property

A simple and versatile approach was developed to support small-sized ZnO nanoparticles with 5 nm on graphene (GR) sheets by the co-precipitation method, and the photocatalytic property was evaluated. The experimental results showed that the resultant GR/ZnO composite was proven to possess a better photocatalytic activity for the degradation of methyl orange (MO) than pure ZnO nanoparticles. When the GR content in composite powder was 0.51 wt. %, the photocatalytic degradation rate for MO come up to about 100% in 90 min. The enhancement in the photocatalytic activity was attributed to the efficient charge transfer of graphene, which retarded the recombination of the photogenerated electrons in the conduction band with holes in the valence band of ZnO nanoparticles.

Enhanced sunlight-driven photocatalytic property of Mg-doped ZnO nanocomposites with three-dimensional graphene oxide/MoS2 nanosheet composites

Graphene oxide (GO) has been the focus of attention as it can enhance the photocatalytic activity of semiconductors due to its large specific surface area and remarkable optical and electronic properties. However, the enhancing effect is not ideal because of its easy self-agglomeration and low electronic conductivity. To improve the enhancing effect of GO for ZnO, three-dimensional GO/MoS2 composite carriers (3D GOM) were prepared by electrostatic interactions and then, Mg-doped ZnO nanoparticles (MZ) were supported on the surface of 3D GOM by utilizing the layer-by-layer assembly method. Compared with GO/Mg-ZnO composite (GOMZ), the resultant three-dimensional GO/MoS2/Mg-ZnO composite (GOMMZ) exhibited excellent photocatalytic performance due to the effective synergistic effect between GO and MoS2 sheet, and its degradation rate was nearly 100% within 120 min of exposure to visible light; this degradation rate was nearly 8 times higher than that of the GOMZ composite. Moreover, the introduction of the MoS2 sheet intensified the photocurrent density of the GOMZ composite and endowed it with optical memory ability.

Low-temperature construction of MoS2 quantum dots/ZnO spheres and their photocatalytic activity under natural sunlight

Zinc oxide (ZnO) nanophotocatalyst is a promising candidate for degrading organic pollutants but has an extremely low photocatalytic activity under nature sunlight. In this work, flower-like MoS2 quantum dots/ZnO (MQ/ZnO) nanospheres with the size of approximately 1.26 μm are prepared at low temperature. The resultant flower-like MQ/ZnO nanospheres displayed higher photocatalytic activity than pure ZnO nanospheres under natural sunlight and without stirring, with the decomposition rate of the MQ/ZnO composites approximately 3.3 times higher than that of the pure ZnO nanospheres. Furthermore, the introduction of MoS2 QDs endowed ZnO nanospheres with optical memory ability. The enhanced sunlight-driven photocatalytic activity is dependent on the unique electrical properties of MoS2 QDs and the synergistic effect between ZnO and MoS2 QDs.

Preparation and Photocatalytic Property of Graphene/TiO2 Composite Powder

Graphene/TiO2 (GR/TiO2) composite powders were prepared by co-precipitation method, and their morphology, structure and photocatalytic property were studied by scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffraction and ultraviolet spectrophotometer, respectively. The experimental results show that the photocatalytic activity of TiO2 is significantly improved by GR. When the content of GR in the composite powder is 7.88%, the GR/TiO2 composite powders treated at 500°C display the good photocatalytic performance in which the degradation volume of methyl orange (MO) approaches 100% within 120 min. The improvement for photocatalytic properties of TiO2 is attributed to the special structure and excellent electrical properties of GR.

Enhanced photocatalytic property of graphene oxide/TiO2 hybrids with WO3 quantum dots

ABSTRACT To improve the photocatalytic activity and endow graphene oxide/TiO2 (GO/TiO2) hybrid with the optical storage ability, WO3 quantum dots (WO3 QDs) were used to modify GO/TiO2 hybrids by sol-gel method, and then the resultant WO3 QDs-GO/TiO2 hybrids were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Experimental results show that WO3 QDs can significantly ameliorate the photocatalytic performance of GO/TiO2 hybrids under visible light, which the reaction rate of WO3 QDs-GO/TiO2 hybrids is about 17 times as much as that of GO/TiO2 hybrids. Whats more, WO3 QDs-GO/TiO2 hybrids possess optical memory performance.

Synthesis of graphene oxide/Bi2O3 based nanohybrids by organic electrolyte-assisted coprecipitation method

ABSTRACT A versatile approach was developed to synthesize graphene oxide/Bi2O3 nanohybrids by organic electrolyte-assisted coprecipitation method. The structure, morphology and photocatalytic property of GO/Bi2O3 hybrids were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and UV-vis spectrophotometer, respectively. Experimental results showed that the tadpole-like MoO2-Bi2O3 hybrids and WO3-Bi2O3 nanorods were covered on the graphene sheets, respectively. Furthermore, the resultant GO/Bi2O3 hybrids possessed strong adsorption ability and high photocatalytic activity for Rhodamine B (RhB).

Preparation and photocatalytic activity of multi-walled carbon nanotubes/Mg-doped ZnO nanohybrids

Abstract Multi-walled carbon nanotubes/Mg-doped ZnO (MWNTs/Zn1-xMgxO) nanohybrids were prepared by co-precipitation method, and their photocatalytic activity for methyl orange (MO) was studied. Experimental results showed that Mg-doped ZnO nanoparticles were successfully deposited on the surface of MWNTs under annealing at 450 °C and 550 °C. The resultant MWNTs/Zn0.9Mg0.1O nanohybrids had better photocatalytic activity for degradation of methyl orange than pure ZnO: the rates of MO photodegradation were 100 % and 30 % for 1 h, respectively. The enhancement in the photocatalytic activity was attributed to the excellent electronic properties of MWNTs and Mg-doping.

Graphene Oxide/ZnO-Bi2O3 Nanoplate Photocatalysis with Strong Adsorption Capacity and High Efficient under Simulated Solar Light

Graphene/ZnO-Bi2O3 nanoplates (GZB) were prepared by means of the low temperature hydrothermal method, and their photocatalytic activity for degradating rhodamine B (RhB) was studied. Experimental results show that the ZnO-Bi2O3 nanoparticles were supported on graphene sheet under the assist of cetyltrimethylammonium bromide (CTAB). Furthermore, the resultant GZB nanoplates exhibited very strong adsorption capacity and high photocatalytic activity, in which the first absorbed ability comes up to about 74.62% within 30 min. Moreover, 90% RhB in solution can be degraded within 100 min under visible light after the sample reach the maximum adsorption.