Mo_2C/γ-Al_2O_3催化剂上苯加氢反应的原位红外光谱研究

采用程序升温反应法制备了钝化态、还原钝化态和新鲜态Mo2C/γ-Al2O3催化剂,结合原位红外光谱表征技术和反应性能评价,考察、比较了三种催化剂苯加氢反应活性.原位红外光谱结果表明,新鲜态Mo2C/γ-Al2O3催化剂在室温就显示了较好的苯加氢反应活性,表现了类贵金属的催化活性.CO吸附在反应前后新鲜态Mo2C/γ-Al2O3催化剂上的对比结果表明,低价态的Mo位(Moδ+(0δ2))是苯加氢反应活性中心.三种催化剂的反应活性结果表明,新鲜态Mo2C/γ-Al2O3催化剂反应活性最好,催化剂寿命最长,失活之后在500°C下H2处理即可恢复原有活性.

Hydrogenation Study of Benzene over a Mo2C/γ-Al2O3 Catalyst by In situ IR Spectroscopy

Passivated, reduced passivated, and fresh Mo₂C/γ-Al₂O₃ catalysts were prepared by temperatureprogrammed reactions with a CH₄/H₂ gas mixture. The results of in situ infrared (IR) analysis revealed that the fresh Mo₂C/γ-Al₂O₃ catalyst displayed the highest level of activity at room temperature, with cyclohexane being detected as the only product. The activity of molybdenum carbide in this reaction was comparable to that of the noble metals. The results from the in situ IR spectra for CO adsorbed onto the fresh Mo₂C/γ-Al₂O₃ catalyst before and after the hydrogenation of benzene showed that Mo₂C was active for the hydrotreating processes and Mo^δ+ (0<δ<2) was the active center for the hydrogenation of benzene. The activities of the three different catalysts for the hydrogenation of benzene were studied, and the results revealed that fresh Mo₂C/γ-Al₂O₃ was the most active catalyst.