稀土元素掺杂的铜基催化剂用于柴油车尾气中碳烟催化氧化的研究

Study of rare earth element Cu-based hydrotalcite-derived mixed oxide catalysts applied for soot removal on diesel exhausts

采用共沉淀法制备了Cu_(1.0)Mg_(2.0)Al_(1.0)水滑石前驱体,并对Al位进行稀土元素Ce和La掺杂改性,焙烧后形成Cu基复合氧化物(记为CMA系列样品),用作碳烟催化燃烧反应.XRD表征测试表明,CMA系列样品主要活性物相是CuO.BET结果说明焙烧后样品具有较大比表面积,可提供更多的催化活性位点.H_2-TPR表征结果说明,水滑石基载体可使铜物种高度分散.碳烟燃烧活性评价表明稀土元素La、Ce的引入可显著提高CMA系列样品的催化活性,由于La元素对Cu物种的抗烧结作用,掺杂量为8%的CMALa8样品催化活性最高.

Cu1.0Mg2.0Al1.0 hydrotalcite-like compounds（HTlc）were prepared by a co-precipitation method.Meanwhile,Al element was substituted by rare earth element Ce and La.The Cu-based hydrotalcite-derived mixed oxides（denoted as CMA）were obtained after calcination and applied for soot combustion.The results of XRD suggest that the main Cu-containing phase in the catalyst is CuO.According to BET data,the specific surface area of catalysts,which were derived from hydrotalcite-like compounds,is large enough to supply more active sites.The results of H2-TPR indicate hydrotalcite-derived mixed oxides can prompt the dispersion of Cu species.The evaluation of soot catalytic activity display that the substitution of rare earth can highly prompt CMA samples performance.Due to the anti-sintering effect of La element on Cu species,the CMALa8 sample exhibits the highest soot combustion activity.