制备Cu(I)/沸石新方法的研究及其表面铜物种的表征

Study of new reduction method of Cu zeolites and its characterization of Cu species

选择 β沸石体系 ,采用水溶液离子交换法引入Cu(Ⅱ )后 ,吸附氨使其转化为Cu2 + (NH3 ) n/ β(n =1～ 4) ,然后通入CO还原 ,在低温 (36 7～ 393K)下可方便地制备纯净的Cu(Ⅰ ) / β ,并应用TPR、XPS、FT IR等方法对还原前后的Cu物种和性质进行了表征研究 ,结果表明 ,还原后Cu(Ⅱ )完全还原为Cu(Ⅰ ) ,样品中不存在Cu(Ⅱ )或Cu(0 )。将该还原方法与常用的H2 还原法、CO还原法、加热抽真空法等进行分析比较 ,发现本方法可克服常用还原方法易发生的深度还原或还原不彻底等弊端 ,且所需还原气CO用量少 ,还原温度低 ,节约能源和原料 ,具有较好的应用价值。

Purified Cu +/β can be conveniently prepared from Cu 2+ /zeolites by ammonia adsorption followed by CO reduction during 367～393K. TPR,XPS,FT IR characterization results show that all Cu 2+ are completely reduced to Cu + without any formation of Cu 0. Comparision of TPR study between the new reduction method and the generally used methods such as reduction by H 2 or CO,it is found that the new one can overcome the disadvantages which there co exist Cu 2+ or Cu 0 in the Cu +/β zeolites.In addition,it can use lower grade of reduction gas and lower temperature,and consumes less CO gas,which make the method easily to be applied in experiment study and industrial application.