H_2还原预处理CuO/γ-Al_2O_3催化剂对其催化燃烧甲苯活性的影响

Catalytic combustion of toluene over copper based catalysts prepared using pretreatment of H_2 reduction

用浸渍法和H2还原预处理法制备两种CuO/γ-Al2O3催化剂,并用N2吸附脱附、XRD、TPR和CO化学吸附对经H2还原处理前后的催化剂进行表征,比较两种催化剂催化氧化(燃烧)甲苯的活性。研究结果表明,与浸渍法制备的CuO/γ-Al2O3催化剂相比,经H2还原预处理,再次焙烧后得到的CuO/γ-Al2O3/HR催化剂对甲苯催化燃烧活性明显提高。XRD和TPR分析表明,H2还原预处理提高了催化剂表面活性组分CuO的分散度、还原能力,同时,还降低了CuO的晶体尺寸,从而提高了催化剂催化氧化甲苯的活性。

The copper based catalysts were prepared by using a wetness impregnation and a pretreatment of H2 reduction for catalystic combustion of toluene,and then characterized separately by N2 adsorption-desorption,Xray diffraction（XRD）,temperature programmed reduction（H2-TPR）by H2and CO-chemisorptions.Activity tests of the catalysts were carried out at atmospheric pressure in a fixed bed reactor.Results showed that the catalytic activity of the catalyst CuO/γ-Al2O3/HR treated with H2 reduction was much higher than that of the catalyst CuO/γ-Al2O3 treated without H2 reduction.The reducibility of CuO on the catalyst CuO/γ-Al2O3/HR was higher than that on the catalyst CuO/γ-Al2O3.Both the dispersion and metal area per gram of copper of the catalyst CuO/γ-Al2O3/HR were higher than that of the catalyst CuO/γ-Al2O3,and the partical sizes of Cu on the catalysts CuO/γ-Al2O3/HR and CuO/γ-Al2O were 11.9and 31.1nm separately.As a consequence of that, the catalytic activity of the catalyst CuO/γ-Al2O3/HR was greatly improved in comparison with the catalyst CuO/γ-Al2O3 pretreated without H2reduction.