摘要
采用程序升温还原技术(TPR)研究CuO-Ag_2O/γ-Al_2O_3双组分及其单组分催化剂的还原特性以及热处理温度对其还原性能的影响.发现不同负载量的CuO-Ag_2O/γ-Al_2O_3催化剂的还原特性有明显差异,反映出催化剂表面存在着不同种类的铜物种.Ag_2O的存在,使催化剂的TPR峰位与单组分CuO/γAl_2O_3的TPR曲线产生明显差异,还原峰发生位移,随Ag_2O添加量的增加,位移增大.对苯的完全氧化反应结果表明,催化剂的氧化活性次序为:CuO-Ag_2O/γ-Al_2O_3>CuO/γ-Al_2O_3>Ag_2O/γ-Al_2O_3热处理温度升高,使催化剂表面铜物种分散状态及其还原性能发生变化从500～900℃,存在一个使钢物种达到最佳分散态的温度.讨论了负载于γ-Al_2O_3载体上的CuO-Ag_2O双组分及其单组分催化剂在还原过程中金属与载体、金属与金属间的相互作用以及热处理温度对其还原性能的影响.
The reducibility of the γ - Al2O3 supported Cu - Ag bimetallic and the individual mono - metallic catalysts and the effect of thermal treatment on the reducibility of these catalysts have been investigated with the temperature-programmed reduction(TPR) technique. It is found that different TPR profiles are produced with different metal contents and different copper species arepresent on the surface of catalysts. There is obvious difference between the TPR profiles of γ -Al2O3 supported Cu - Ag bimetallic and the mono - metallic catalysts and the displacement increase with the content of Ag. The order of activity of catalyst for benzene oxidation is: CuO -Ag2O/γ- Al2O3 >CuO/γ- Al2O3 > Ag2O/γ - Al2O3. The results show that the dispersion of copper species and the reducibility of the catalysts are affected by the variation of treatment temperature. The optimal dispersion of copper species occurs at a temperature between 500 and900℃.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
1997年第1期42-48,共7页
Acta Chimica Sinica
