中文摘要：

分别对Al2O3和SiO2担载的不同含量铱（Ir）催化剂进行了H2程序升温还原、CO微量吸附量热和红外研究．结果表明，还原后，Ir／Al2O3上存在金属态Ir^0和氧化态Ir^δ＋两种物种，CO在催化剂表面主要以线式和孪生吸附态存在，测量的CO吸附热为两种吸附形式的平均吸附热．提高还原温度和Ir担载量，Ir／Al2O3表面CO线式吸附物种的比例增加，从而导致CO吸附热值的升高．而在Ir／SiO2上Ir物种主要为金属态Ir^0，CO吸附都以线式吸附为主，在所考察的条件下CO吸附热随Ir担载量和还原温度的变化不明显．

英文摘要：

Ir/Al2O3 and Ir/SiO2 with Ir loadings of 2 %, 10 %, and 20% were investigated by H2 temperature-programmed reduction, microcalorimetry, and FT-IR. For Ir/Al2O3, there existed both Ir^0 and Ir^δ＋ species. A major carbonyl band, varied with the average particle size, was due to CO linearly adsorbed on Ir^0, while an intense pair of bands observed at 2 080 and 2 004 cm^-1 was assigned to gem-dicarbonyl species adsorbed on Ir^δ＋ . The adsorption heat could be the average heat produced by the formation of both gem-dicarbonyl and linear species. The relative intensities of the Ir^0-CO species were enhanced as the Ir loading and the reduction temperature increased, which led to an increase in the adsorption heat. For Ir/SiO2, several bands ranged in 2 100 - 2 000 cm^-1 were identified and attributed to the linearly bonded CO to larger and smaller Ir^0 clusters. As a result, the adsorption heat maintained almost constant though the loading and the reduction temperature increased.