摘要
以碱性共沉淀法制备了Cu_(x)Co_(y)Al_(z)-LDHs(x:y:z=3:0:1,0:3:1,1:2:0,1:2:1)催化剂前驱体,焙烧后在固定床连续微反应器中评价了其合成气制低碳醇的催化性能。运用XRD、N_(2)吸/脱附、H_(2)-TPR等技术手段对样品进行了表征。结果表明:Cu_(x)Co_(y)Al_(z)催化合成低碳醇遵循表面碳物种插入机理,其中CuCo_(2)Al催化剂具有最好的反应活性,其CO转化率和醇选择性分别为21.74%和35.70%,且产物中C_(2+)OH占总醇的60.34%。Al的引入可以提高Cu、Co的分散性,并与Co共存产生大量对C_(2+)OH生成至关重要的强碱性位,使得Cu_(x)Co_(y)Al_(z)催化剂综合性能最优;Co的引入能增加比表面积,并产生更强的碱性位,促使Co_(3)Al和CuCo_(2)都有高的C_(2+O)H占比,但烃含量也较高;Cu、Al共存不会产生强碱性位,使得Cu3Al的整体活性很低,产物以甲醇为主,C_(2+)OH占比很低。
Catalyst precursors Cu_(x)Co_(y)Al_(z)-LDHs(x:y:z=3:0:1,0:3:1,1:2:0,1:2:1)were prepared by alkaline co-precipitation method.After calcination,the catalytic performance of the catalyst for the synthesis of low carbon alcohols from syngas was evaluated in a fixed bed continuous micro-reactor.The catalysts were characterized by XRD,N_(2) adsorption/desorption and H_(2)-TPR.The results show that the synthesis of lower alcohols catalyzed by Cu_(x)Co_(y)Al_(z) follows the mechanism of surface carbon species insertion.And the CuCo_(2)Al catalyst has the best reaction activity,with CO conversion and alcohol selectivity are 21.74% and 35.7% respectively,and C_(2+)OH accounts for 60.34% of the total alcohols.The introduction of Al can improve the dispersion of Cu and Co,and coexist with CO to produce a large number of strong alkali sites which are very important for the formation of C_(2+)OH,which makes the comprehensive performance of Cu_(x)Co_(y)Al_(z) catalyst optimal.The introduction of Co can increase the specific surface area and generate stronger alkaline sites,which makes both Co_(3)Al and CuCo_(2) have higher proportion of C_(2+)OH,but higher hydrocarbons conten.The coexistence of Cu and Al does not produce strong alkaline sites,so the overall activity of Cu_(3)Al is very low,and the product is mainly methanol,at the same time,the proportion of C_(2+)OH is very low.
作者
张文文
栾春晖
黄伟
ZHANG Wen-wen;LUAN Chun-hui;HUANG Wei(State Key Laboratory of Clean and Efficient Coal Utilization,Taiyuan University of Technology,Taiyuan 030024,Shanxi,China;College of Chemistry and Chemical Engineering,Taiyuan University of Technology,Taiyuan 030024,Shanxi,China)
出处
《天然气化工—C1化学与化工》
CAS
北大核心
2021年第5期43-48,87,共7页
Natural Gas Chemical Industry
基金
国家自然科学基金项目(21336006)
山西省自然科学基金项目(201601D011021,201601D202017)
山西太原理工煤转化技术工程有限公司资助(201803D121043)。
