担载型钌催化剂吸附CO性能的原位红外研究

in situ iR STUDIES OF CO ADSORPTION AND HYDROGENATION OVER SUPPORTED RUTHENIUM CATALYST

用原位红外研究了ＣＯ的吸附与脱附，ＣＯ／Ｈ２的共吸附及反应，考察了焙烧温度对Ｒｕ／Ａｌ２Ｏ３及Ｒｕ／ＳｉＯ２催化剂的影响结果表明，经不同温度焙烧的催化剂样品，其吸附性能有很大差别．随着焙烧温度的升高，金属－载体相互作用增强，导致ＣＯ吸附量减少．Ｒｕ／Ａｌ２Ｏ３吸附的ＣＯ较稳定，而Ｒｕ／ＳｉＯ２吸附的ＣＯ在高温易脱附、各不同ＣＯ吸附态间，多重态更易发生反应．在未焙烧的Ｒｕ／ＳｉＯ２上，低压ＣＯ／Ｈ２反应生成较多的甲烷，焙烧过的催化剂上则只有很少的甲烷生成；在未焙烧的Ｒｕ／Ａｌ２Ｏ３上．反应生成少量甲烷和甲酸，而高温焙烧过的催化剂上则不生成这些产物．结果还表明，Ｒｕ／Ａｌ２Ｏ３上金属－载体作用更强；在金属－载体相互作用弱的钌中心上，ＣＯ易于加氢．

he features and reactivities of CO adsorbed on 1% Ru/SiO2 and1% Ru/Al2O3 catalysts and their correlation with calcination temperature have been studied by in situ IR spectroscopy. The adsorption properties of the SiO2- and Al2O3-supported ruthenium catalysts calcined atdifferent temperatures are varied significantly. The interaction betweenmetal and support is enhanced and CO adsorption decreases as the calcination temperature incresaes. The CO adsorbed on Ru/SiO2 catalyst isnot so stabble as on Ru/Al2O3 catalyst and is easier to be desorbed athigher temperature. The multiple CO among various adsorbed stateshas higher reactivity with H2. The CO+H2 reaction on uncalcined Ru/SiO2 catalyst at low pressure forms more amount of CH4. On the otherhand, IR bands of CO adsorbed on calcined Ru/SiO2 catalyst are weak,and only little methane is produced by hydrogenation. On uncalcinedRu/Al2O3 catalyst, small amount of methane and formic acid areformed, while on the calcined one, no methane or no formic acid is detected, indicating that CO hydrogenation on the sites with weak metalsupport interaction is easier to take place.