CuCl/γ-Al_2O_3体系的原位红外光谱研究

in situ IR SPECTROSCOPIC STUDY OF CuCl/ γ Al 2O 3 SYSTEM

ＣｕＣｌ／γ┐Ａｌ２Ｏ３体系的原位红外光谱研究＊朱月香谢有畅唐有祺（北京大学物理化学研究所，北京１００８７１）高兴涛辛勤（中国科学院大连化学物理研究所催化基础国家重点实验室，大连１１６０２３）关键词氯化亚铜，氧化铝，一氧化碳，一氧化氮，吸附，红外光谱...

The removal of nitrogen oxide is important for air pollution control. Catalytic decomposition is a very promising way to remove NO. CuCl/ γ Al 2O 3 system showed high activity for NO decomposition, but the activity decreased gradually during the reaction. In this paper, CuCl/ γ Al 2O 3 system was investigated by in situ IR technique using CO and NO as probe molecules, the reason for the sample deactivation was also investigated. CuCl/ γ Al 2O 3 was prepared by mixing CuCl with pseudoboehmite (AlO(OH)) and then being calcined at 400￣500℃ in N 2 for 2 h. The sample was triturated to fine powder then pressed into self supporting wafer. It was mounted in an IR cell which was designed for in situ pretreatment and IR measurement. After the sample was evacuated at 450℃ for 2 h, the IR spectrum of CO NO coadsorption was recorded at room temperature. It was found that only the adsorption of CO on Cu + (￣2121 cm -1 ) and NO on Cu 2+ (￣1880 cm -1 ) appeared, and the absorption intensity of Cu + CO was much higher than that of Cu 2+ NO. It was also found that there was a turning point in the plot of Cu + CO intensity vs CuCl content, corresponding to the dispersion capacity of CuCl on γ Al 2O 3. In order to reveal the deactivation mechanism of the system, the NO decomposition process was simulated and studied by in situ IR technique. The results demonstrated that the deactivation of the system was due to the oxidation of copper species with lower valence on the sample surface to higher valence copper species.