预处理条件对Pt/Al_2O_3催化氧化NO性能的影响

Influence of Temperature and Feed Gas on Degreening Effect during the NO Oxidation over Pt/Al_2O_3 Catalyst

考察了温度和反应气氛对新鲜态Pt/Al_2O_3催化剂上NO氧化过程中的degreening效应的影响。利用活性评价实验测试不同条件下NO氧化活性,用H2程序升温还原(H2-TPR)表征了degreening效应过程中催化剂中Pt的价态变化。在degreening效应过程中,新鲜态Pt/Al_2O_3催化剂中与载体结合较弱的Pt Ox物种在温度低于300℃时被NO还原为Pt^0;与载体结合较强的PtO_x物种在温度高于400℃时分解成Pt^0。新鲜态Pt/Al_2O_3催化剂经过第一次程序升温反应后,NO氧化活性位Pt^0的增加导致了其NO氧化能力提高。

The influence of temperature and feed gas on degreening effect during NO oxidation over Pt/Al2O3 catalyst was investigated by a single variable method. Activity measurements were carried out to evaluate NO conversion. Meanwhile, H2 -TPR experiments were performed to characterize the catalyst. It was found that PtOx, species which has weak interaction with support could be reduced by NO at temperatures blow 300℃whereas PtOx species having strong interaction with support were decomposed to Pt0 above 400℃. Indicating that the number of Pt0, as the NO oxidation active site, will increase after the first temperature programmed reaction.