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采用等体积浸渍法制备了BaO改性的单Pd催化剂,并用BET,CO化学吸附,XRD,H2-TPR,NH3-TPD,XPS对催化剂进行了表征,考察了其对甲醇、CO、C3H8的催化氧化性能。结果表明,BaO的添加可使Pd粒子高度分散,催化剂表面易还原氧物种量增多,还原速率加快,还原性能得以改善;同时还可增强金属与载体间的电子效应,使Pd向氧化态过渡,Ce4+向还原态Ce3+过渡,并在金属与载体界面间产生大量具有活性的氧物种,进而提高了催化剂对甲醇和CO的低温活性,T50可分别降低26,21℃。催化剂表面酸性降低以及较高氧化态Pd物种形成可能是导致C3H8转化率下降的主要原因。
The BaO modified Pd catalysts were prepared by the same volume impregnation method. The catalysts were characterized by BET, CO chemisorption, XRD, H2-TPR, NH3-TPD and XPS. Oxidation performance. The results show that the addition of BaO can make the Pd particles highly dispersed, the amount of the easily reducible oxygen species on the surface of the catalyst increases, the reduction rate increases, and the reduction performance can be improved. At the same time, the electron effect between the metal and the support can be enhanced, Ce4 + transition to the reduced state Ce3 +, and produce a large number of active oxygen species between the metal and the carrier interface, thereby increasing the low temperature activity of the catalyst on methanol and CO, T50 can be reduced by 26,21 ℃. Decreasing acidity of the catalyst surface and formation of higher oxidation state Pd species may be the main reason for the decrease of C3H8 conversion.