Pd-CeO2/SiC催化剂的制备及其在CO和C3H6氧化反应中的催化性能

分别以蔗糖和硅酸钠为碳源和硅源，硫酸为催化剂，采用溶胶-凝胶法和碳热还原法合成SiC；以其为载体，Pd为活性组分，CeO₂为助剂，采用浸渍法制备Pd-CeO₂/SiC催化剂。考察催化剂制备方法、助剂CeO₂添加量和还原温度等对催化剂在CO和C₃H₆氧化反应中活性的影响。结果表明， 采用分步浸渍法制备的催化剂具有较高活性， CeO₂添加质量分数2%时制备的0.5%Pd-2%CeO₂/SiC催化剂经200 ℃预还原后，对CO和C₃H₆氧的最低完全转化温度分别为210 ℃和215 ℃，CeO₂助剂可显著提高金属Pd在催化剂表面分散度，与Pd产生相互作用，使Pd还原峰向低温移动，提高了催化剂活性。

Preparation of Pd-CeO2/SiC catalysts and their catalytic properties for CO and C3H6 oxidation

By using sodium silicate,saccharose and sulfuric acid as silicon source,carbon source and catalyst,respectively,SiC support was synthesized via the carbothermal reduction method associated with the sol-gel technology.SiC supported palladium catalysts with CeO2 as the promoter were prepared by incipient impregnation method.The catalytic properties of Pd-CeO2/SiC catalysts related to the preparation methods,promoter CeO2 contents and pre-reduction temperatures were investigated by means of XRD,CO pulse adsorption,H2-TPR and CO and C3 H6 catalytic oxidation test.The results showed that the samples prepared with stepwise impregnation method exhibited higher catalytic activity than those prepared with co-impregnation method.For the sample with 2wt％ CeO2 （0.5％ Pd-2％ CeO2/SiC） after pre-reduction at 200 ℃,the lowest complete conversion temperature for CO and C3 H6 were 210 ℃ and 215 ℃,respectively.The addition of CeO2 substantially increased the palladium dispersion on the catalyst surface,and the interreaction between palladium and CeO2 alSo made the redox peak of palladium shift to low temperature,which was responsible for the high catalytic activity.