Papers by Author: Yue Liu

Abstract: There are many areas in the world where the ground water has been contaminated by arsenic. One process to purify the water is to use TiO₂ to adsorb the arsenic. As the TiO₂ surface can be cleaned and reused, it has a promising potential as a water purifier. In this paper, the plane-wave function method, based on the density functional theory, has been used to calculate the structures of arsenic(III) on a perfect TiO₂ anatase (1 0 1) surface. All the arsenic(III) solution species such as H₃AsO₃, H₂AsO₃^-1, HAsO₃^-2 and AsO₃^-3 are put onto the surface with many different possible structures to obtain the adsorption energy. Based on the adsorption energy, the bidentate binuclear (BB) adsorption configurations of arsenic(III) on the surface are more favorable at low concentrations, whereas BB form and monodentate mononuclear (MM) form may coexist at higher concentrations. The models and results fit well with published experimental results. The results and conclusions will be of benefit to further research on arsenite adsorption and its photocatalytic oxidation on a TiO₂ surface.

Abstract: α-MnO2, β-MnO2 and Mn2O3 were synthesized from birnessite followed by acid treatment and subsequently calcined under different conditions. These catalysts were used for catalytic combustion of dimethyl ether (DME) and characterized by XRD, BET and H2-TPR techniques. The results showed that the catalytic activity of α-MnO2, β-MnO2 and Mn2O3 are higher than that of birnessite. Larger specific surface area as well as the better reducibility of Mn species in the manganese oxides might be the main contribution for the DME combustion activity.