Ce改性ZSM-5分子筛载Pd催化剂的CeO2-Pd协同作用研究

摘要

CeO2-Pd interactions in Ce-modified ZSM-5 supported Pd catalyst for oxidation of CO and CH4 is investigated by XRF, XRD, SEM and CH4-TPR. The results show that amount of supported Pd in Ce-ZSM-5 is increased. For Pd/Ce-ZSM-5, adsorption starting-temperature of CH4 is decreased. Cerium oxide (CeO2) is mainly in Pd/Ce-ZSM-5 catalyst. Activated species of CO oxidation is Pd. Conversion rate of CO oxidation is increased because of CeO2-Pd interaction. Activated species of CH4 oxidation are Pd and PdO. Transformation of Pd→PdO is promoted by supply-storage oxygen of CeO2. Activity of Pd/Ce-ZSM-5 for CO and CH4 oxidation is enhanced due to interaction between CeO2 and Pd.%采用XRF、XRD、SEM和CH4-TPR表征手段，研究了Ce改性ZSM-5分子筛载Pd催化剂在CO、CH4氧化过程中的CeO2-Pd协同作用。结果表明，经Ce改性后ZSM-5分子筛的载Pd量提高；Pd/Ce-ZSM-5催化剂对 CH4的起始吸附温度降低；Pd/Ce-ZSM-5催化剂中 Ce 主要以 CeO2形态存在。Pd是CO的催化氧化活性物种，CeO2-Pd协同作用可促进CO的氧化。Pd和PdO均是CH4的催化氧化活性物种，CeO2的供氧-储氧特性有助于Pd→PdO的转化，CeO2与Pd的相互作用使Pd/Ce-ZSM-5催化剂具有高的CO和CH4催化氧化活性。