Ru-La_2O_3/γ-Al_2O_3催化剂合成、表征及CO选择氧化

The Preparation,Characterization and its Catalytic Performance of Ru-La_2O_3/γ-Al_2O_3 Catalysts for CO Selective Oxidation

采用浸渍法制备系列Ru-La2O3/γ-Al2O3复合氧化物催化剂,通过XRD、H2-TPR、CO-TPR、XPS、BET等方法对催化剂进行表征,考察La2O3的加入量、预处理方法对催化剂上CO选择氧化性能的影响.结果表明,110-170℃时Ru1La6/Al2O3催化剂上CO转化率达到99%以上,氧气利用率达55.7%以上.和Ru/Al2O3相比,Ru1La6/Al2O3催化剂在较低温度具有高活性,活性温度区间变宽.适量La2O3的加入促进了活性组分在载体表面分散,提高了催化剂的活性.经氢气预处理的Ru1La6/Al2O3催化剂活性最佳,催化剂上Ru物种结合能降低,表面钌物种活性位增多,且表面晶格氧浓度增大,更有利于CO气体在催化剂表面上的氧化反应.

The Ru-La2O3/γ-Al2O3 catalysts with various La2O3 contents were synthesized by impregnation method,the catalysts were tested for the CO selective oxidation and characterized by XRD,XPS,H2-TPR,CO-TPR.BET techniques.The effects of various parameters（La2O3 loading and pretreatment methods） on Ru-La2O3/Al2O3 catalysts structure and performance were investigated.The results showed that higher CO conversion（99%） and O2 useful ratio（55.7%）were obtained at 110～170 ℃ on the Ru1La6/Al2O3.La2O3 promoted the dispersion of Ru species,thus enhance the catalytic activity.When Ru1La6/Al2O3 catalyst was heated in a H2/N2 mixed gas flow as the pretreatment,the CO oxidation activity was highly improved at a low temperature range,the 3d electron binding energies of Ru species of the catalyst decreased,the amounts of surface Ru species and surface lattice oxygen concentration increased,which could be of benefit for the oxidation reaction of CO.