贵金属纳米催化剂在苯甲醇部分氧化制备苯甲醛过程中具有较高的反应活性,产物苯甲醛选择性较低.采用一锅法制备TiO2 改性的Au-Pd/TiO2-SiO2 纳米合金催化剂并用于苯甲醇部分氧化反应.对催化剂结构表征关联反应进行评价.结果表明:少量TiO2 的引入会改善贵金属纳米颗粒在载体表面的分散度,调变了金钯合金表面的电子结构,提高反应活性,并显著提高载体表面Lewis酸位的数量,从而大幅提高苯甲醛选择性;大量TiO2 的引入会导致金钯合金程度降低,产生大量的Bronsted酸位,使得反应活性和产物选择性都大幅降低.
Noble metal nanoparticle catalysts exhibit high catalytic activity in the partial oxidation of benzyl alcohol to benzal-dehyde.However,the selectivity of benzaldehyde is low.TiO2 modified Au-Pd/TiO2-SiO2 nano alloy catalysts were prepared by a one pot method and applied for benzyl alcohol partial oxidation.It is found that the introduction of a small amount of TiO2 increases the metal dispersion on the support surface,and modifies the electronic structure of the Au-Pd alloy surface,and improves the reaction activity.Also,the number of Lewis acid sites on the support surface are increased,which improves benzaldehyde selectivity.However,the introduction of a large amount of TiO2 destroys the alloying of Au-Pd and produces a large number of Bronsted acid sites,which greatly reduces the reaction activity and product selectivity.