摘要
采用浸渍法制备了蛋壳型Pd/α-Al2O3催化剂,并用于CO和亚硝酸甲酯气相合成草酸二甲酯反应,考察了活性层厚度对催化剂活性的影响.采用偏光显微镜和电感耦合等离子光谱技术对催化剂进行了表征.结果表明,调节前驱体溶液的pH值可以控制活性组分在载体上的分布,从而得到不同钯层厚度的催化剂.这种活性组分位于催化剂外表面的蛋壳型催化剂可以提高活性组分的利用,使亚硝酸甲酯的转化率较高.另外考察了活性组分Pd负载量对催化剂浸渍深度和活性的影响,确定了催化剂活性组分的适宜负载量为0.10%,浸渍深度为16μm.
Egg-shelled Pd/α-Al2O3 catalysts with different active layers were prepared by means of impregnation. The catalytic activity for the synthesis of dimethyl oxalate from CO and methyl nitrite was investigated. The catalyst pellets were characterized by polarized optical microscopy and ICE The results showed that with a fixed amount of palladium the depth of the active layer was controlled by the pH of the precursor solution. Moreover, for optimum conversion of methyl nitrite and yield of dimethyl oxalate, the active component of palladium should be placed in a thin layer at the external surface of the pellet. Furthermore, the depth and catalytic activity influenced by palladium loadings were also investigated. The appropriate palladium loading is 0.10% and the impregnate depth is 16μm.
出处
《催化学报》
SCIE
CAS
CSCD
北大核心
2009年第3期213-217,共5页
