Ni对Pd/Al2O3密偶催化剂催化性能的影响

考察了助剂Ni对以改性氧化铝为载体的单Pd密偶催化剂的影响.结果表明，掺杂Ni可以明显改善对C3H8的催化性能，尤其对老化催化剂效果显著.此外， Ni的添加使老化催化剂Pd/Al2O3的起燃温度(T50)和完全转化温度(T90)分别降低31和30oC.单反应测试结果表明，添加Ni能明显提高对C3H8+ NO反应的催化性能.采用H2程序升温还原、CO吸附、高倍透射电镜和X射线光电子能谱等手段对新鲜和老化催化剂进行了表征.结果表明，掺杂Ni不仅可以抑制活性组分PdOx的烧结，减少金属态Pd0的产生，而且可以提高PdOx物种的可还原能力和有效比表面积.

Promotion of a Pd/Al2O3 close-coupled catalyst by Ni

The influence of a nickel promoter on the catalytic behavior of a modified alumina supported Pd close-coupled catalyst was investigated. Doping with nickel improved the catalytic activity for the reactions of C3H8, especially over the aged catalyst.T50 andT90 of the aged Pd catalyst were de-creased by 31 and 30 °C, respectively. The single reaction results revealed that doping with Ni pro-moted the catalytic activity for the C3H8 + NO reaction. The fresh and aged catalysts were character-ized by H2-temperature-programmed reduction, CO chemisorption, high resolution transmission electron microscopy, and X-ray photoelectron spectroscopy, which revealed that the doping with Ni inhibited the sintering of active PdOx species and the formation of undesired metallic Pd0, and led to improved reducibility of active PdOx and increased the surface area of PdOx species.