低负载量Pt/γ-AlOOH催化氧化VOCs的性能研究

Study on performance of low loading Pt/γ-AlOOH for VOCs catalytic combustion

通过直接吸附纳米颗粒的方法制备一系列负载量极低的Pt/γ-Al OOH催化剂,并探究了催化剂对苯、甲苯、二甲苯的催化氧化性能和对不同类型VOCs(CVOCs)的普适性能。其中,0.02%Pt/γ-Al OOH表现出优良的催化性能。在质量分数为1 000μg/g、空速为24 000 m L/g·h时,对三苯系95%转化率的温度分别为190、176℃和185℃。在200℃条件下,对甲苯持续反应100 h转化率仍然保持在100%。对催化剂进行XRD、TEM、BET表征的结果表明,金属颗粒在载体表面分散良好,粒径在2.5 nm左右,载体形貌无明显改变。XPS和H_2-TPR结果显示,催化剂的活性中心主要是高价态的铂(Ptδ+)并以Pt Ox形式存在。

With the method of directly adsorbing nano-particles,a series of ultra-low loadings Pt/γ-Al OOH catalysts have been prepared,and their catalytic combustion performance against benzene,toluene,xylene（ BTX） and their universally applicable performance on different types of volatile organic compounds（ VOCs） are studied. As a result,0. 02% Pt/γ-Al OOH catalyst shows a good catalytic performance,with T95 reaching 190℃（ benzene）,176℃（ toluene）and 185℃（ xylene） respectively at a concentrate of 1 000 μg/g and a space velocity of 24 000 m L/g·h. At a temperature of 200℃,this catalyst can make toluene degradation maintain 100% after 100 h continuous reaction. The catalyst is characterized by XRD,TEM and BET,which shows that Pt particles arewell-dispersed on the surface of supports,particle sizes are around 2. 5 nm,and the morphology of supports has changed a little. XPS and H2-TPR results show that the active center of catalyst mainly exists in the form of Ptδ ＋（ Pt Ox） species.