用脉冲D2反应研究CeO2在Co-CeO2/SiO2费托合成催化剂中的促进作用机理

 采用脉冲D2反应研究了CeO2在Co-CeO2/SiO2费托合成催化剂中的作用机理. 通过比较在Co-CeO2/SiO2和Co/SiO2催化剂上的脉冲D2反应实验结果发现, CeO2可以提高载体表面 Si-OH 的H-D同位素交换活性和 Si-OH 中H参与CO加氢反应的活性; CeO2不仅增加了催化剂表面活性碳物种的总量,而且活性碳物种以链增长单体-CH2-为主,因而有利于增加费托合成反应速率和链增长几率; CeO2的加入明显提高了催化剂表面碳原子的加氢反应速率,从而减少了碳沉积.

Studies on Promotion Mechanism of CeO2 in Co-CeO2/SiO2 Catalyst for Fischer-Tropsch Synthesis Using D2 Pulse Reaction

The role of the CeO_2 promoter in the Co-CeO_2/SiO_2 catalyst playing in Fischer-Tropsch synthesis (FTS) was investigated by means of the D_2 pulse reaction. The D_2 pulse reaction results over Co-CeO_2/SiO_2 and Co/SiO_2 catalysts showed that the addition of CeO_2 increased the catalytic activity of Co/SiO_2 for the H-D isotopic exchange and the reactivity of H from Si-OH for CO hydrogenation. The addition of CeO_2 increased the total amount of active carbon species on the surface of Co/SiO_2 and made the chain growth unit -CH_2- the dominating one, which consequently benefited the increase of the FTS reactivity and the chain growth possibility. The addition of CeO_2 into Co/SiO_2 also improved the hydrogenation reactivity of carbon atoms on the surface of Co-CeO_2/SiO_2, which led to a decrease in carbon deposition.