ZnO对Au-Pd/CeO_2催化剂甲醇部分氧化制氢性能的影响

Effect of ZnO on Au-Pd/CeO_2 Catalysts in the Partial Oxidation of Methanol

采用沉积沉淀法制备了Au-Pd双金属催化剂,研究了ZnO对Au-Pd/CeO2催化剂甲醇部分氧化性能的影响,并运用N2吸附、XRD、UV-Vis、TPR、H2-TPD和CO-IR等手段对催化剂进行了表征.结果表明,ZnO的引入减少了Pd活性中心,降低了催化剂的活性,但提高了催化剂H2选择性和降低了CO选择性.Au-Pd/ZnO-CeO2催化剂的TPR表明,在约200℃时开始有部分ZnO被还原,CO-IR显示CO吸收峰移向低频,这些结果表明Au-Pd/ZnO-CeO2催化剂中Pd和Zn之间发生了相互作用.Pd和Zn之间相互作用抑制了Pd的甲醇分解活性,有利于H2和CO2的生成,使Au-Pd/ZnO-CeO2催化剂表现出较高的H2选择性和较低的CO选择性.

Au-Pd/CeO2 bimetallic catalysts have been prepared by deposition-precipitation （DP） method, and the influence of ZnO on the performance of Au-Pd/CeO2eatalysts for partial oxidation of methanol has been evaluated. N2adsorption, XRD, UV-Vis, TPR, H2-TPD and CO-IR has been used to characterize the catalysts. Although the introduction of ZnO reduces the amount of Pd active site and consequently reduces the catalyst activity, the catalyst shows higher H2 selectivity and lower CO selectivity than those of Au-Pd/CeO2. TPR reveals that some of ZnO can be initially reduced at about 200℃ And CO-IR shows that the position of the bands is shifted to lower frequencies for Au-Pd/ZnO-CeO2 catalyst. These reveal interaction between Pd and Zn, which restrains methanol decomposition of Pd and favors formation of H2 and CO2, consequently Au-Pd/ZnO-CeO2 catalyst exhibiting higher H2selectivity and lower CO selectivity for partial oxidation of methanol.