【作者】 罗小军； 王榕； 魏可镁；

【Author】 LUO Xiao-jun, WANG Rong, WEI Ke-mei (National Research Center of Chemical Fertilizer Catalysts, Fuzhou University, Fuzhou 350002, China)

【机构】 福州大学化肥催化剂国家工程研究中心；

【摘要】 通过共沉淀法制备了Ru/CeO2氨合成催化剂,考察了还原条件对其氨合成性能的影响。通过CO化学吸附和XPS等表征手段,对还原条件影响Ru/CeO2催化剂氨合成性能的原因进行探讨。结果表明:还原温度为500℃、还原时间为4h时制备的催化剂样品具有较好的氨合成活性。在给定的还原温度下,还原时间不仅明显地影响金属钌的分散度,而且会影响载体CeO2表面氧的还原。Ru/CeO2催化剂的高活性归因于钌粒子分散度提高以及CeO2表面氧易还原两者相互作用的结果。更多还原

【Abstract】 The Ru/CeO2 catalyst was prepared by co-precipitation method. In a typical procedure, the aqueous solution of RuCl3·3H2O and Ce(NO3)3·6H2O was mixed with vigorous stirring. Then, an aqueous solution of KOH was added drop wise to the aqueous mixture, followed by stirring for 1h. After that, the suspension solution was cooled to room temperature. The resulting precipitate was centrifuged and washed with distill water until no Cl- was detected by AgNO3 solution. The obtained precipitate was dried at 120℃ for 24h and reduced at 500℃ at a set time under H2+N2 mixture gas stream. As prepared catalysts were characterized by CO chemisorption and XPS to explore the cause resulting in their significant difference of catalytic activities. Experimental results showed that the Ru/CeO2 catalyst, which reduced at 500℃ for 2h, presented the best ammonia synthesis activity. The promoted catalytic activity of Ru/CeO2 catalyst can be attributed to the improvement of the dispersion of Ru particle and the promoted reduction of surface oxygen of the support.更多还原