Ce改性对CuLDH催化CO_(2)加氢制甲醇性能的影响  

Effect of Ce modification on the performance of CuLDH catalyst for CO_(2) hydrogenation to methanol

作　　者：刘昊然 于志庆 黄文斌 魏强[1] 姜鹏 周亚松[1] LIU Haoran;YU Zhiqing;HUANG Wenbin;WEI Qiang;JIANG Peng;ZHOU Yasong(State Key Laboratory of Heavy Oil Processing,China University of Petroleum,Beijing 102249,China;CNPC Kunlun Capital Co.,Ltd,Haikou 571127,China)

机构地区：[1]中国石油大学(北京)重质油全国重点实验室,北京102249 [2]中国石油集团昆仑资本有限公司,海南海口571127

出　　处：《燃料化学学报（中英文）》2024年第2期159-170,共12页Journal of Fuel Chemistry and Technology

基　　金：国家自然科学基金(22078360)资助。

摘　　要：通过向CuMgAl水滑石(CuLDH)催化剂中添加不同量的Ce,合成了一系列Ce改性的CuLDH-Cex催化剂。采用X射线衍射(XRD)、N2吸附-脱附(BET)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)等分析手段对催化剂的理化性质进行表征。结果表明,添加Ce会改变Cu-LDH催化剂的水滑石结构,适量的Ce会增大催化剂的比表面积,改善了Cu颗粒的分散度。同时,适量的Ce有利于增加催化剂表面强碱性位点的密度和氧空位的数量,促进了CO_(2)的吸附和转化。Ce有利于调变催化剂表面的Cu^(+)/Cu^(0)比例,较高的Cu^(+)/Cu^(0)比例有利于甲醇的生成。当Ce/Cu比例为0.3时,在空速为9000 mL/(g·h),温度为240℃,压力为2.5 MPa的条件下,催化剂的CO_(2)的转化率为7.5%,甲醇选择性为78.4%,甲醇的时空收率最高可达362.8 g/(kg·h)。通过原位红外光谱(in-situ DRIFTS)证明CuLDH-Ce0.3催化剂在CO_(2)加氢合成甲醇过程中遵循HCOO*反应路径。A series of Ce modified CuLDH-Cex catalysts were synthesized by adding different amounts of Ce to CuMgAl hydrotalcite(CuLDH)catalysts.The physicochemical properties of the catalysts were characterized by X-ray diffraction(XRD),N2 adsorption-desorption(BET),transmission electron microscopy(TEM),X-ray photoelectron spectroscopy(XPS),etc.The results showed that the addition of Ce changed the hydrotalcite structure of CuLDH catalyst,and an appropriate amount of Ce increased the surface area of the catalyst and improved the dispersion of Cu particles.At the same time,an appropriate amount of Ce was beneficial for increasing the density of strong alkaline sites and the number of oxygen vacancies on the catalyst surface,promoting the adsorption and conversion of CO_(2).Ce was beneficial for adjusting the Cu^(+)/Cu^(0) ratio on the catalyst surface,and a higher Cu^(+)/Cu^(0) ratio was conducive to the formation of methanol.When the Ce/Cu ratio was 0.3,the catalyst exhibited higher activity with 7.5%CO_(2) conversion,78.4%methanol selectivity and 362.8 g/(kg·h)spatiotemporal yield at 240℃under 2.5 MPa with a GHSV=9000 mL/(g·h).It was proved by in-situ DRIFTS that CuLDH-Ce0.3 catalyst followed HCOO*reaction path during CO_(2) hydrogenation for methanol.

关 键 词：CE 水滑石 CO_(2)加氢 碱性位 氧空位 甲醇 

分 类 号：O643[理学—物理化学]