负载型Pd/TiO2和Pd-Ag/TiO2催化剂的乙炔选择性加氢催化性能

利用程序升温还原(TPR)、X-射线衍射(XRD)、CO吸附-红外光谱(CO-IR)、电子顺磁共振(EPR)和微型催化反应评价等手段, 研究了负载Pd/γ-Al2O3, Pd/TiO2和Pd-Ag/TiO2催化剂的结构和乙炔选择性加氢催化性能. 结果表明, Pd/TiO2催化剂具有较Pd/γ-Al2O3催化剂更优良的乙炔选择性加氢催化性能, 这与Pd-TiO2之间的强相互作用密切相关. Pd-TiO2之间的强相互作用不仅使负载型钯金属催化剂具有较高的乙炔加氢催化选择性, 而且具有较高的乙炔加氢催化活性. Pd/TiO2催化剂中添加Ag 组分后, Pd金属可促进Ag+的还原并可能形成Pd-Ag合金, 催化剂的乙烯选择性虽有所增加, 但乙炔转化率和乙烯收率下降.

Catalytic Properties of Supported Pd/TiO2 and Pd-Ag/TiO2 Catalysts for Selective Hydrogenation of Acetylene

The structure and catalytic properties of supported Pd/TiO2 and Pd-Ag/TiO2 catalysts for selective hydrogenation of acetylene have been studied by using microreactor tests combined with temperature-programmed reduction (TPR), X-ray diffraction (XRD), infrared spectroscopy of adsorbed carbon monoxide (CO-IR), and electronic paramagnetic resonance (EPR). The results indicate that the Pd/TiO2 catalyst exhibits better catalytic performance than Pd/γ-Al2O3 catalyst for selective hydrogenation of acetylene, which can be correlated to the strong metal-support interaction (SMSI) between Pd and TiO2 in the Pd/TiO2 catalyst. Adding Ag component to Pd/TiO2 catalyst results in formation of Pd-Ag alloy, leading to an increase in selectivity of acetylene hydrogenation to ethylene, but a decrease in the activity of acetylene hydrogenation.