摘要
分别以碳纳米管(CNTs)和68%浓HNO3处理的CNTs为载体,采用超声辅助的浸渍法制备负载型Cu O-CeO_2复合氧化物催化剂,用于富氢气中CO选择氧化。采用XPS和LRS对预处理前后CNTs管的结构与表面性质进行研究。采用XRD和H2-TPR对催化剂结构进行表征。结果表明,经浓HNO3处理的CNTs载体表面含氧官能团—COOH相对含量提高了约68%,且表面缺陷增多,有助于催化剂活性组分的沉积和分散。以此负载的Cu O-CeO_2催化剂上Cu O物种具有较好的分散性,晶粒尺寸较小,催化剂表现出强的低温氧化还原能力,且表面CO氧化活性位增多,对CO选择性氧化具有低温高活性,T50低至90℃,反应温度低于140℃保持高选择性,且CO完全转化反应温度窗口拓宽宽至30℃。
Using carbon nanotubes （CNTs） and 68% HNO3 treated CNTs as the carriers, respectively, CuO - CeO2 supported catalysts for selective oxidation of CO in rich hydrogen atmosphere were prepared by ultrasonic assisted impregnation method. The structure and surface properties of carbon nanotubes before and after pre - treatment were investigated by means of X - ray photoelectron spectroscopy and Laser Raman spectroscopy. The structures of the catalysts were characterized with X - ray diffraction and temperature - programmed reduction. The results showed that on the surface of carbon nanotubes treated by concentrated HNO3 , the relative content of functional groups --COOH was improvedby about 68% and the surface defects increased ,which contributed to the deposition and dispersion of the active components of the catalyst. CuO - CeO2 catalyst with HNO3 treated carbon nanotubes as the support possessed high dispersion of CuO species and small crystallite sizes and exhibited strong low -temperature redox capacity, and its surface activity sites for CO oxidation at low- temperature increased. The catalyst exhibited high low - temperature activity for CO selective oxidation. The T50 reduced to 90 ℃.High selectivity was maintained when reaction temperature was below 140℃ and the temperature window of total CO conversion was broadened to 30 ℃.
出处
《工业催化》
CAS
2017年第9期18-23,共6页
Industrial Catalysis
基金
国家自然科学基金青年基金项目(21406174)
