热解温度对CuZnAl催化剂CO加氢制备低碳醇性能的影响

Effects of pyrolysis temperature on performance of CuZnAl catalyst for CO hydrogenation to lower alcohols

将完全液相法与热解法结合制备了CuZnAl催化剂,并在固定床反应器上进行了CO加氢制备低碳醇活性评价,结合XRD、XPS、O_(2)-TPO-MS、H_(2)-TPR、N_(2)吸/脱附以及NH;-TPD-MS表征手段,考察了热解温度对催化剂结构和性能的影响。结果表明,随着热解温度的升高,Cu-Zn-Al间相互作用增强,Cu的电子向Zn和Al物种转移,Cu氧化程度增大;催化剂表面碳含量降低,弱酸中心数量减少,比表面积先升高后降低,CO转化率则与比表面积呈现顺变关系。700℃热解所制备催化剂上CO转化率最高,达到23.6%;总醇选择性则随热解温度的升高而下降,350℃热解所制备催化剂上总醇选择性最高,为41.9%。

CuZnAl catalyst was prepared by combining complete liquid phase method and pyrolysis method,and the activity of CO hydrogenation to lower alcohols was evaluated in a fixed-bed reactor.The effects of pyrolysis temperature on the structure and performance of the catalyst were investigated by XRD,XPS,O_(2)-TPO-MS,H_(2)-TPR,BET and NH_(2)-TPD-MS.The results show that with the increase of pyrolysis temperature,the interaction between CuZnAl increases,the electrons of Cu transfer to Zn and Al species,and the degree of Cu oxidation increases.The carbon content on the catalyst surface decreases,and the number of weak acid centers decreases.The specific surface area first increases and then decreases,and the CO conversion shows a positive relationship with the specific surface area.The catalyst prepared by pyrolysis at 700℃ has the highest CO conversion,up to 23.6%.The total alcohol selectivity decreases with the increase of pyrolysis temperature,and the total alcohol selectivity on the catalyst prepared by pyrolysis at 350℃is the highest,up to 41.9%.