Study on the preparation of ZrO2 supported Cu/ZnO ultrafine composite catalyst powders by hydrothermal method
|School||Kunming University of Science and Technology|
|Keywords||Hydrothermal Zirconia Copper/Zinc oxide Catalyst|
In recent years, the greenhouse gas emissions and the energy sustainable development, industrial printing and dyeing bleaching wastewater treatment gradually caused wide attention around the world. Because the copper base catalyst is effective catalyst for CO, CO2or syngas hydrogenation of preparation of methanol or dimethyl ether. And based on ZnO semiconductor photocatalyst for printing and dyeing bleaching wastewater has high rate of photodegradation. In this paper, based on the domestic and international research present situation and existing problems of CO, CO2or syngas catalytic hydrogenation of methanol synthesis and processing industry and dyeing bleaching wastewater, the Cu/Zn/Zr/O catalyst key technologies of preparation, the characterization of phase and morphology, catalytic performance were systemed research.Because of the valence of copper species in the copper base catalyst (Cu0, Cu+Cu2+) for catalytic synthesis of methanol mechanism remains controversial. The mainly research purpose of this paper is through one step hydrothermal method to prepared copper base catalyst, and copper species contain two or more among elemental Cu, Cu2O and CuO.The ultrafi ne ZrO2powder were prepared by chemical precipitation and hydrothermal crystallization, the results show that,0.2g PEG-4000, the end point pH value of zirconium hydroxide titration is9, hydrothermal temperature is180℃, hydrothermal time is12h, the mineralizer concentration of NaOH is lmol/L, the high dispersion short clavite ultrafine ZrO2powder can be produced.The CuZn alloy powders were prepared by mechanochemical method at room temperature, the results show that, the electronic compounds Cu5Zn8of CuZn alloy and elemental Cu mixture can be got after the atomizing copper and zinc powder balling120minutes in high-energy ball mill.The pure ZnO, pure CuO and Cu/ZnO composite powder were prepared by hydrothermal oxidation method and hydrothermal crystallization, the results show that, the products of ball mill zinc powder, atomized zinc powder, zinc nitrate after hydrothermal are pure ZnO powder. The morphology were long needle, short rod, uniform short rod. The ZnO powder were prepared by atomized zinc powder after hydrothermal, which photocatalytic degradation efficiency can reach95.985%.The products are pure CuO powder of Cu(NO3)2under the condition of without/with PEG-4000after hydrothermal, the morphology is flake and granular, respectively. The photodegradation efficiency of pure CuO is very low, so that, which is not suitable for photocatalytic degradation of industrial printing and dyeing bleaching waste water of catalyst. The products and morphologys of ball mill CuZn alloys, CuZn alloys+Cu(NO3)2, atomized zine powder+Cu(NO3)2, Cu(NO3)2+Zn(NO3)2after hydrothermal are quite different. The Cu/ZnO composite powder prepare by copper zinc source of CuZn alloys+Cu(NO3)2after hydrothermal, which photocatalytic degradation efficiency can reach99.381%.The carrier of ZrO2loading Cu/ZnO composite catalyst powder was prepared by one step hydrothermal oxidation and hydrothermal crystallization method. The results show that, the products and morphologys of different copper zinc source+ZrOCl2after hydrothermal great different, the specific surface area of Cu(NO3)2+Zn(NO3)2+ZrOCI2after hydrothermal is58.04m2/g, Analyzed by XPS, H2-TPR、NH3-TPD and catalytic performance found that, the copper species are highly dispersed and content is higher, the hydrothermal products highest catalytic performance is CuZn alloys+Cu(NO3)2+ZrOCl2, because of its products containing Cu, Cu2O, CuO at the same time, which illustrate the center activity of catalytic to synthesis methanol is Cu0, Cu+, Cu2+.