Ni的引入对Pd/Al2O3催化甲烷燃烧性能的影响

采用浸渍法制备了Ni掺杂的Pd/Al2O3催化剂,考察了其低浓度甲烷催化燃烧活性和水热稳定性.结果表明,随着Ni的引入及其含量的增加,Pd/Al2O3催化剂性能明显提高,Ni含量至20%时,在0.4%CH4,4%H2O和空气平衡的原料气组成,80000h-1空速和600oC条件下反应150h后,CH4转化率仍能保持在97.5%以上.X射线衍射、H2程序升温还原、NH3程序升温脱附和透射电镜等结果表明,NiAl2O4晶相的形成改善了载体酸性和活性组分的分散度,从而提高了催化剂性能.

Effect of Ni Addition on Methane Catalytic Combustion Performance of Pd/Al2O3 Catalyst

Pd/Al2O3 catalyst samples modified by Ni promoter were prepared and tested for methane catalytic combustion under lean-fuel condition.A series of Pd catalyst samples with different Ni contents were characterized by N2 adsorption,X-ray diffraction,temperature-programmed reduction,temperature-programmed desorption of ammonia and transmission electron microscopy.In addition,the performance of the catalyst samples for lean methane combustion was studied.The results showed that the addition of Ni effectively improved the activity and hydrothermal stability of catalyst samples due to the formation of NiAl2O4 spinel.As Ni content increased,the NiAl2O4 content increased,thus the performance of the catalyst increased.For Pd/Ni-Al2O3 sample with 20% Ni,methane conversion remained 97.5% after 150 h at 600 oC.Weaker acidity of the supports and the well dispersion of Pd particles on the supports contributed by NiAl2O4 phase might be the reason of high performance of the catalyst.