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本文利用NO或/和CO吸附的TPD-MS方法,结合IR和XPS对还原态的Co,Mo,Co-Mo/Al_2O_3催化剂进行了深入考索.结果表明,还原态的Co-Mo/Al_20_3表面上存在着两种吸附NO的Mo中心.弱吸附NO(T_(max)为100℃)可被吸附的CO取代和强吸附NO(T_(max)为300℃)不能被CO取代.同时存在三种吸附NO的CO中心,T_(max)分别为80℃、180℃和330℃.前两者能吸附CO,后者只吸附NO.IR结果对这些不同的Mo中心和Co中心的存在提供了进一步旁证.XPS结果表明提高还原温度,Mo/Al比保持恒定,但Mo~(4+)浓度增加,而Co/Al比却因部分Co进入Al_2O_3体相而降低。
In this paper, NO and / and CO adsorption of TPD-MS method, combined with IR and XPS reduction of Co, Mo, Co-Mo / Al_2O_3 catalyst conducted in-depth examination results show that the reduction of the surface of the Co-Mo / Al_20_3 There are two kinds of Mo centers on which NO is adsorbed.The weakly adsorbed NO (T max max of 100 ℃) can be adsorbed on CO and the strongly adsorbed NO (T max max of 300 ℃) can not be replaced by CO. The CO centers adsorbed by NO species were 80 ℃, 180 ℃ and 330 ℃, respectively.The first two could adsorb CO, the latter only adsorbed NO.The IR results provided the existence of these different Mo centers and Co centers XPS results show that when the reduction temperature is increased, the Mo / Al ratio remains constant, but the concentration of Mo ~ (4 +) increases while the Co / Al ratio decreases due to the partial Co entering the Al 2 O 3 bulk.