柴油车尾气净化催化剂的制备与评价

Preparation and Estimate of Catalyst for Purification of Diesel Engine Exhaust

采用浸渍法得到Pt-Co/γ -Al2 O3 ,用XRD、XPS气相色谱、分光光度法进行活性评价。结果表明 ,催化剂中的活性非贵金属在高温下将转化为尖晶石 ,尖晶石活性较为稳定 ,因而催化剂中的非贵金属的高分散金属态和周期性转化的氧化态是催化剂作用的活性中心 ,同时贵金属与非贵金属之间存在着相互作用 ,能很好的提高催化剂的催化活性。Pt-Co/γ -Al2 O3 对柴油车尾气中的HC、CO有比较明显的氧化作用 ,其中HC氧化成H2 O ,CO氧化生成CO2 ,NO还原成NO2 。

The catalyst for purification of diesel engine exhaust was prepared and evaluated by x-ray photoelectrum spectrosocopy(XPS)、XRD、GC、SP. It was shown that activ non-noble metal in catalyst would be transformed into spinel, and the activity of spinel was fine dispersal state and recurrent oxidation state of non-noble metal. At the same time, minim noble methal and non-noble metal were interactional. It resulted in an increase of the activity of this catalyst. Thus, it can be seen that Pt-Co/γ-Al_2O_3 catalyst has evident effect to purify the diesel engine exhaust gas. The NO was reduced in the catalyst, Co was the active center of CO and other oxidates, the content of CO purification was less than that of unburning HC purification.