Mo/SiO_2及V改性的Mo/SiO_2催化剂的微孔特征及其对甲烷部分氧化合成甲醛反应的影响

INFLUENCE OF MICROPORE PROPERTIES OF Mo/SiO 2 AND Mo V/SiO 2 CATALYSTS ON PARTIAL OXIDATION OF MATHANE TO FORMALDEHYDE

在常压下评价了Ｍｏ／ＳｉＯ２催化剂的制备条件对反应性能的影响．利用Ｎ２的吸附等温线计算了ＭｏＶ／ＳｉＯ２催化剂的比表面积和孔径分布，进而讨论了不同的Ｖ加入量对Ｍｏ／ＳｉＯ２催化剂的微孔特征及其催化性能的影响，找到了适宜的Ｖ／Ｍｏ质量比及使甲醛收率最高的最佳孔径．通过ＸＲＤ和ＴＥＭ的测试分析讨论了制备条件对微观状态的影响和Ｖ与Ｍｏ之间的相互作用．

The catalytic properties of Mo/SiO 2 and Mo V/SiO 2 catalysts prepared in different conditions have been estimated under atmospheric pressure. The specific surface area and pore diameter distribution have been calculated by BET equation and cylindrical pore model. Influence of V usage on micro pore properties of Mo V/SiO 2 catalysts and the reaction of partial mathane oxidation to formaldehyde has been studied. Proper V/Mo mass ratio and optimum most possible pore diameter making the yield of CH 2O the highest were found to be m (V)/ m (Mo)=1 and 7 5 nm, respectively. At the reaction temperature of 750℃, the best CH 2O yield is more than 4%. XRD and TEM results indicate that the microstate of Mo(V)/SiO 2 catalysts is affected by preparation condition and interaction of V and Mo produces Mo 6V 9O 40 active phase including V ion and V-O-Mo, V=O bonds, which possesses better catalytic properties than MoO x (Mo Ⅴ ion).