【摘要】 为认识合成催化剂Pt/CeO2-CNTs与商用催化剂PtRu/C(E-TEK)的催化性能和结构特点,用CO溶出法和恒电位氧化法比较了这两种催化剂对CO的电氧化活性,运用循环伏安法和恒电位氧化法比较了这两种催化剂对甲醇的电氧化活性.CO电氧化实验结果表明,PtRu/C上CO的电氧化活性明显优于Pt/CeO2-CNTs;甲醇电氧化实验结果却表明,Pt/CeO2-CNTs与PtRu/C上甲醇电氧化表观活性相当.为从结构特点上解释PtRu/C上CO电氧化和甲醇电氧化活性的不一致,对PtRu/C进行了循环伏安扫描和CO溶出实验.结果表明,PtRu/C的甲醇电氧化电流之所以没有预期高,一是由于Pt比表面积不够大,同时Pt-Ru之间协同作用有待提高.本研究结果表明,尽管Ru对Pt上CO电氧化有显著助催化作用,但要充分发挥其对Pt上甲醇电氧化的助催化作用,需同时提高Pt表面积和Pt-Ru接触界面.该结论对设计甲醇电氧化催化剂具有普适意义.更多还原

【Abstract】 To gain insight into the catalytic and structural properties of as-prepared Pt/CeO2-CNT and as-received PtRu/C (E-TEK), CO stripping and constant potential electro-oxidation of CO ad-layer were con-ducted with Pt/CeO2-CNT and PtRu/C. Besides, cyclic voltammetry (CV) scanning and constant potential electro-oxidation of methanol were conducted as comparison. Tests with CO electro-oxidation indicated that CO ad-layer was more readily electro-oxidized on PtRu/C than on Pt/CeO2-CNT while tests with methanol electro-oxidation showed that Pt/CeO2-CNT and PtRu/C exhibited nearly the same apparent activity. To probe the structural reason behind this discrepancy, cyclic voltammetry scanning and CO stripping methods were ap-plied to PtRu/C. Analysis based on experimental results indicates that the structural reason for the not-so-high-as-expected activity for methanol electro-oxidation on PtRu/C lies in two aspects: one is the lim-ited specific area of Pt and the other is the decreased Pt-Ru interfaces due to Ru dissolution. The study showed that simultaneously increasing the specific area of Pt and Pt-Ru interfaces was significant for effective co-catalysis of Ru, the intrinsically more active component toward CO and methanol electro-oxidation.更多还原