CuO-WO_3-ZrO_2的结构和性质对苯甲醛加氢反应催化性能的影响

Effect of Structure and Properties of CuO-WO_3-ZrO_2 on Hydrogenation Catalytic of Benzaldehyde

采用共沉淀法制备了不同CuO和WO_3含量的CuO-WO_3-ZrO_2催化剂.利用X射线衍射(XRD)、扫描电子显微镜(SEM)、X射线荧光光谱(XRF)、N2气物理吸附、氢气程序升温还原(H2-TPR)、X射线光电子能谱(XPS)及程序升温脱附(TPD)等手段对催化剂的结构和表面性质进行了表征.结果表明,WO_3的引入可以调变ZrO_2的晶型,从而使催化剂的比表面积和孔径发生变化,促进CuO在催化剂表面的分散,并影响催化剂的酸碱性.在苯甲醛加氢制备苯甲醇反应中,以CuO质量分数为18%,WO_3质量分数为10%的CuO-WO_3-ZrO_2为催化剂时苯甲醛单程转化率达到92. 03%,产物苯甲醇的选择性为94. 76%.

CuO-WO3-ZrO2 catalysts were prepared by co-precipitation method. Structures and surface properties of the catalysts were characterized by X-ray powder diffraction(XRD),scanning electron microscope(SEM),X-ray fluorescence(XRF),N2 physisorption,temperature programmed hydrogen reduction(H2-TPR), X-ray photoelectron spectroscopy(XPS) and temperature programmed desorption(TPD).Addition of WO3 into CuO-ZrO2 induced the transformation of ZrO2 from monoclinic to tetragonal phases,improved the dispersion of CuO species,changed the acid-base properties of the catalysts as well as the catalyst textural features such as surface area and the average pore diameter. As a consequence,the catalytic performance for the hydrogenation of benzaldehyde to benzyl alcohol was greatly promoted by the introduction of WO3.For the optimal catalyst containing 10%(mass fraction) CuO and 18%(mass fraction) WO3,the conversion of benzaldehyde and the selectivity to benzyl alcohol reached 94. 76% and 92. 03%,respectively.