F-T组分改性KCuZrO2催化剂上CO加氢合成异丁醇的性能研究

Study on the performance of F-T component modified KCuZrO 2 catalyst for CO hydrogenation to isobutanol

采用共沉淀法分别制备了不同F-T组分(Fe、Co、Ni)改性的KCuZrO 2催化剂,并用于催化CO加氢合成异丁醇。通过BET、XRD、TEM、XPS、H 2-TPR、CO-TPD以及in-situ DRIFTS对催化剂进行了表征。结果显示,F-T组分的加入促进了乙醇和丙醇的形成,但是对异丁醇选择性影响不同。结果表明,Fe促进了催化剂中各组分的分散,活性组分Cu在催化剂表面发生了富集,提高了H 2/CO活化吸附;另外,KFeCuZrO 2的催化剂表面含有较多的C 1物种,有利于乙醇和丙醇进一步发生β-加成反应得到异丁醇,而Co和Ni改性的催化剂上缺少足够的C 1物种,因此,异丁醇的选择性并未明显增加。Co的引入对催化剂结构以及Cu的分散影响不大,但是Co改性后催化剂性能有所下降,其原因是催化剂发生了失活;Ni添加后催化剂比表面积有所减小,且催化剂表面Cu/Zr物质的量比也降低到0.19,催化剂粒径增大,Cu-Zr之间相互作用减弱,异丁醇选择性降低。

KCuZrO 2 catalysts modified with different F-T elements(Fe,Co,Ni)were prepared by co-precipitation method and then were tested for isobutanol synthesis from catalytic CO hydrogenation.The catalysts were characterized by N 2 adsorption and desorption experiments(BET),XRD,TEM,XPS,H 2-TPR,CO-TPD and in situ DRIFTS.The results showed that the addition of F-T components promoted the formation of ethanol and propanol,and had different effects on the selectivity of isobutanol.The characterization results showed that Fe promoted the dispersion of catalyst components,and enriched the active component Cu on the catalyst surface,which improved the active adsorption of H 2 and CO.In addition,more C 1 species were formed on the KFeCuZrO 2 catalyst surface,and these C 1 species could further react with ethanol and propanol to produce isobutanol.However,the catalysts modified by Co and Ni lacked sufficient C 1 species,so the selectivity of isobutanol did not increase significantly.The introduction of Co had little effect on the structure of catalyst and the dispersion of Cu,but the activity of catalyst decreased after Co addition,which might be due to the deactivation of catalyst.After adding Ni to the catalyst,the specific surface area decreased and the particle size increased,and the Cu/Zr molar ratio on the catalyst surface also decreased to 0.19.The interaction between Cu-Zr was weakened,and the isobutanol selectivity was also reduced.