催化学报 ›› 2024, Vol. 66: 152-167.DOI: 10.1016/S1872-2067(24)60117-8

• 论文 • 上一篇    下一篇

离子液体辅助构建CeO2介孔单晶材料强化CO2和醇合成碳酸酯

黄杰林a,b, 王洁a,b, 段浩楠b, 陈嵩嵩a,b, 张军平b,c, 董丽b,c,*(), 张香平b,*()   

  1. a中国科学院大学化学工程学院, 北京 100049
    b中国科学院过程工程研究所, 离子液体清洁过程北京市重点实验室, 中国科学院绿色过程与工程重点实验室, 介科学与工程全国重点实验室, 北京 100190
    c河南大学郑州新兴产业技术研究院, 龙子湖新能源实验室, 河南郑州 450000
  • 收稿日期:2024-05-10 接受日期:2024-08-12 出版日期:2024-11-18 发布日期:2024-11-10
  • 通讯作者: *电子邮箱: ldong@ipe.ac.cn (董丽),xpzhang@ipe.ac.cn (张香平).
  • 基金资助:
    中国科学院煤炭清洁燃烧与低碳利用先导科技专项(XDA29030202);国家自然科学基金(22178356);广东省重点领域研发计划(2020B0101370002)

Constructing mesoporous CeO2 single-crystal particles in ionic liquids for enhancing the conversion of CO2 and alcohols to carbonates

Jielin Huanga,b, Jie Wanga,b, Haonan Duanb, Songsong Chena,b, Junping Zhangb,c, Li Dongb,c,*(), Xiangping Zhangb,*()   

  1. aSchool of Chemical Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
    bBeijing Key Laboratory of Ionic Liquids Clean Process, CAS Key Laboratory of Green Process and Engineering, State Key Laboratory of Mesoscience and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
    cLongzihu New Energy Laboratory, Zhengzhou Institute of Emerging Industrial Technology, Henan University, Zhengzhou 450000, Henan, China
  • Received:2024-05-10 Accepted:2024-08-12 Online:2024-11-18 Published:2024-11-10
  • Contact: *E-mail: ldong@ipe.ac.cn (L. Dong),xpzhang@ipe.ac.cn (X. Zhang).
  • Supported by:
    Clean Combustion and Low-carbon Utilization of Coal, Strategic Priority Research Program of the Chinese Academy of Sciences(XDA29030202);National Natural Science Foundation of China(22178356);Key-Area Research and Development Program of Guangdong Province(2020B0101370002)

摘要:

CO2转化为羰基化合物是CO2利用的重要途径之一, 包括合成一系列高值化学品和原料, 如酮、醛、酯等. 以CO2和醇为原料合成碳酸酯的反应被认为是CO2循环利用和增值转化的有效途径, 具有显著的商业应用潜力和环境效益. 然而, CO2分子的热力学稳定性和动力学惰性使反应需要在高温和高压条件下进行. 尽管研究人员不断开发出用于CO2转化的催化剂, 但仍缺少能够在温和条件下活化CO2的新型催化材料. 因此, 在温和条件下高效催化CO2和醇制备碳酸酯是当前面临的重要挑战.

本文提出采用改进溶剂热法制备了介孔CeO2单晶材料, 以离子液体(IL)/甲醇混合液作为溶剂, 通过缓慢引入水蒸气参与CeO2样品的形成和结晶, 引导CeO2纳米晶粒的生长模式和表面化学性质, 以达到有效调节表面的Lewis酸碱位点, 改善催化性能的目的. 随后, 研究了CeO2材料的表面物化性质和初级聚集程度对催化CO2和乙二醇(EG)合成碳酸乙烯酯(EC)的影响. 活性测试结果表明, 制备的催化剂在0.5 MPa和100 °C的反应条件下可以实现CO2和EG到EC的高效转化, 其中由IL和甲醇协同调制的CeO2-IL-M样品在催化CO2和EG合成EC时的性能达到46.22 mmol g-1 h-1, 是未加入IL时合成的CeO2催化剂的50.6倍. X射线衍射、透射电镜、物理吸附、化学吸附、拉曼光谱和X射线光电子能谱的测试结果表明, 催化剂合成环境可以改善催化剂的物相结构、孔结构和表面化学性质. 其中, 催化剂的活性与催化剂表面的弱酸性和碱性位点的浓度呈正相关, 表面羟基和表面缺陷可以作为活性中心来促进EG和CO2的活化, 协同地促进EC的生成. 通过18O同位素标记实验研究了CO2中氧原子在产物中的分配情况, 采用原位红外光谱进一步探究了表面缺陷和表面羟基存在下的可能催化路径和机理, 结果表明, 在2-氰基吡啶和CeO2(111)亲核加成的特殊均质-异质结构下产生N-强碱性位点. 同时, EG两端-OH基团上的质子被脱除并转移到2-氰基吡啶的N-强碱性位上形成-C-NH2基团. CO2分子在中间体和表面氧空位作用下被活化为O2-和CO*基团, 其中CO*和-OCH2CH2O-结合并发生内酯化反应形成产物碳酸乙烯酯. 中间态O2-作用于-C-NH2基团上的碳原子并产生2-吡啶酰胺. 该过程得益于酸碱位点的协同催化作用, 酸碱位点协同促进底物EG两端-OH的去质子化与CO2的羰基化并生成EC.

综上所述, 本文利用离子液体辅助构建了CeO2催化材料, 可在温和条件下高效催化转化CO2和醇合成碳酸酯, 为CO2高效温和转化催化剂的设计和研发提供了新思路.

关键词: 二氧化铈, 离子液体, 单晶材料, 表面氧空位, 羰基化反应

Abstract:

Catalysts for CO2 value-added conversion have been extensively explored, but there is still a lack of systematic design for catalysts that achieve efficient CO2 conversion under mild conditions. Herein, we explored a mesoporous CeO2 single-crystal formed with the regulation of ionic liquids, which catalyzed the effective carbonylation reaction with CO2 under mild reaction conditions. By altering the synthetic environment, a series of uniform mesoporous CeO2 particles with atomically aligned single-crystal frameworks were constructed, which have different surface physicochemical properties and primary aggregation degree. The prepared mesoporous CeO2 single-crystal achieved efficient activation of CO2 and alcohols at 0.5 MPa CO2 and 100 °C, and the CeO2-IL-M catalyst shows optimal catalytic performance in the synthesis of ethylene carbonate with 46.22 mmol g-1 h-1, which was 50.6 times as high as that of the CeO2 obtained without ionic liquids. Subsequently, the catalytic pathway and mechanism of carbonylation reaction with CO2 on mesoporous CeO2 single-crystal were studied via React-IR spectra and C18O2 labeling experiments. The research provides a new strategy for controllable nanoscale assembly of mesoporous single-crystal materials and expands the application range of single-crystal materials, aiming to develop novel catalytic materials to meet industrial needs.

Key words: Cerium dioxide, Ionic liquid, Single-crystal material, Surface oxygen vacancy, Carbonylation reaction