担载的NaRuCo_3(CO)_(12)络合物及其分散型Ru-Co双金属催化剂

担载于Al_2O_3上的NaRuCO_3(CO)_(12)络合物在IR光谱上出现类似于Ru(CO)_2O_2络合物特征带的羰基带,在300～400℃左右变强,在CO中尤为明显。在以ZrO_2为载体时出现与原来络合物相近的弱羰基带。当CO吸附于以Al_2O_3为载体的脱羰基催化剂上时,发现在氧化态催化剂上也出现了与担载络合物相似的吸收带,在还原态催化剂上只出现线式带。吸附于以ZrO_2为载体的脱羰基催化剂上的CO不出现CO的IR吸收带,在He中亦无TPD脱附物,在H_2中却可发生加氢反应生成CH_4。从Na~+和ZrO_2协同效应角度,探讨了CO在上述两种分散型催化剂上吸脱附行为不同的原因。

SUPPORTED NaRuCo_3(CO)_(12) COMPLEXES AND THEIR DISPERSED Ru-Co BIMETALLIC CATALYSTS

The carbonyl band of NaRuCo3(CO)12/Al2O8 is similar to the characteristic band of Ru(CO)2O2 complex. For NaRuCo3(CO)u/ZrO2, the carbonyl bands corresponding to terminal and bridged forms are very weak. During TPDE of the supported complexes in He , the products are composed of larger amount of CO2, less CO and trace of CH4. When CO is adsorbed on the oxidized Ru-Co/Al2O3 catalyst, the absorption band of CO is similar to the carbonyl band of the supported complex. The linear absorption band on the reduced catalyst is observed. The low temperature peak corresponding to weakly adsorbed CO is composed of CO, the high temperature peak corresponding to stronger adsorbed CO is composed of CO2. During TPSR in H2, the adsorbed CO is hydrogenated to CH4. It is noticed that when CO is adsorbed on the reduced Ru-Co/ZrO2, no absorption band of CO is found in IR spectra and no desorbed product is observed in TPD profile. TPSR profile shows that the reaction product is composed of CH4. The effect of Na+ and the carrier on the species and surface hydrogenation of CO over both dispersed Ru-Co catalysts is discussed.