燃料电池用Cu-Ce(La)O_x变换催化剂

Cu-Ce(La)O_x water-gas shift catalysts for fuel cells

对采用共沉淀法制备的Cu Ce(La)Ox高温变换催化剂进行了研究,包括中和pH值、中和温度、焙烧温度和方式以及CuO、CeO2和LaOx含量对催化剂性能的影响。5%CuO CeO2 La(10%)Ox高温变换催化剂的最佳制备工艺条件为:pH=11,中和温度54℃,400℃焙烧4h。催化剂的最佳质量分数配比是:CuO为20%,CeO2为70%,LaOx为10%。XRD晶相分析表明,5%Cu Ce La(10%)Ox催化剂中除了主相CeO2以外,还出现了Cu与La形成的钙钛矿型复合氧化物Cu LaO2,且CuLaO2高度均匀地分散在主相CeOx中;还原态中除了CeO2、CuLaO2外,还出现了Cu单质。因此,这类催化剂的活性中心不可能是简单的CuLaO2或Cu,这使得催化剂无论氧化态还是还原态都具有基本相同的活性。催化剂的活性位形态结构尚需做进一步研究。

This paper studies Cu-Ce(La)O_x water gas shift catalysts prepared by co-precipitation, including the influence of neutralization pH, neutralization temperature, calcination temperature and content of CuO, CeO_2 and LaO_x. The optimum preparation condition for 5%CuO-CeO_2-La(10%)O_x catalyst is as follows:neutralization temperature 54 ℃,pH 11,calcining at 400 ℃ for 4 h. The optimum CuO∶CeO_2∶LaO_x is 20∶70∶10(atomic ratio). XRD results showed that perovskite CuLaO_2 were highly dispersed in the main phase CeO_2 in oxide-state 5%CuO-CeO_2-La(10%)O_x catalyst; there exist CeO_2 and CuLaO_2 and Cu phase in the reduced-state catalyst, which indicated that it is unlikely that CuLaO_2 or Cu are the only active sites for the water-gas shift reaction. The active sites for water gas shift reaction might have more complicated structures, which result in mostly identical activity for both oxide-state and reduced-state catalyst.