Response surface methodology(RSM) was employed to optimize the control parameters of TiO_2/graphene with exposed {001} facets during synthesis, and its enhanced photocatalytic activities were evaluated in the photodegradation of toluene. Experimental results were in good agreement with the predicted results obtained using RSM with a correlation coefficient(R^2) of 0.9345. When 22.06 mg of graphite oxide(GO) and 2.09 mL of hydrofluoric acid(HF) were added and a hydrothermal time of 28 h was used, a maximum efficiency in the degradation of toluene was achieved. X-ray diffraction(XRD), transmission electron microscopy(TEM), and scanning electron microscopy(SEM) were employed to characterize the obtained hybrid photocatalyst. The electron transferred between Ti and C retarded the combination of electron–hole pairs and hastened the transferring of electrons, which enhanced the photocatalytic activity.
Yifei WangZhiyang ZhangQianqian ShangXin TanHongmei Wang
An efficient visible-light-responsive BiOBr/TiO_2 heterojunction nanocomposite was fabricated successfully using in-situ depositing technique at room temperature by introducing Bi OBr onto the surface of TiO_2 nanobelts pre-prepared by hydrothermal reaction and etched with H_2SO_4. The obtained particles were characterized by XRD, SEM, TEM, XPS, UV-Vis DRS and PL techniques. BiOBr/TiO_2 heterojunction nanocomposites with different mass ratios of m(Bi OBr)/m(TiO_2) were discussed in order to get the best photocatalytic activity, and BiOBr/TiO_2-1.0 was proved to be the optimal mass ratio. BiOBr/TiO_2-1.0 exhibited excellent photocatalytic activity in the degradation of Rh B compared with TiO_2 nanobelts, pure Bi OBr and the mechanical mixture of TiO_2 nanobelts and Bi OBr. At last, a possible mechanism of photocatalytic enhancement was proposed.
