CeO_2改性SiO_2-CuO复合氧化物的制备和表征以及催化氧化脱硫性能

采用不同方法、不同负载量、不同焙烧温度制备CeO_2改性的SiO_2-CuO-CeO_2复合氧化物催化剂,并对其进行X射线衍射分析、扫描式电子显微镜、TG-DSC、N_2吸附-脱附和H_2-TPR等表征.在温和条件(65℃、常压)下,以过氧化氢为氧化剂,乙腈为溶剂,苯并噻吩(BT)为模型硫化物,考察SiO_2-CuO-CeO_2复合氧化物催化剂的氧化脱硫性能,确定复合氧化物的最佳制备工艺条件.结果表明,适量的添加CeO_2可以提高CuO在SiO_2上的分散度、比表面积和孔径,提高复合氧化物的活性;溶胶-凝胶法制备的SiO_2-0.1CuO-0.02CeO_2复合氧化物,在500℃下焙烧,催化剂活性最高,脱硫率最高为81.6%.催化剂的重复使用5次,脱硫率仍可达到60.0%.

Preparation and Characterization of CeO2 Modified SiO2-CuO Composite Oxide Catalysts and Its Catalytic Oxidation Desufurization Performance

CeO2 modified SiO2-CuO-CeO2 composite oxide catalysts were prepared by using different methods,different loadings,different calcination temperature.The catalysts were characterized by X-ray diffraction (XRD),scanning electron microscope (SEM),thermogravimetry and differential scanning calorimetry(TG-DSC),N2 adsorption-desorption and temperature-programmed reduction by H2 (H2-TPR).Under mild conditions (65 ℃,atmospheric pressure),the oxidative desulfurization performance of SiO2-CuO-CeO2 composite oxide catalysts were investigated under the condition of hydrogen peroxide as the oxidant,acetonitrile as a solvent,benzothiophene (BT) as a model sulfide.Finally,this paper established the best preparation conditions of the composite oxide.The results showed that the addition of appropriate amount of CeO2 into the catalyst increases the dispersion of CuO,the specific surface area,pore size and the activity of the complex oxide.The SiO2-0.1 CuO-0.02CeO2 composite oxide were prepared by sol-gel method at calcination temperature of 500 ℃ had the highest activity,oxide desulfurization rate was 81.6％.After the catalyst was reused for five times,the desulfurization rate still reached 60.0％.