催化学报 ›› 2027, Vol. 92: 328-339.DOI: 10.1016/S1872-2067(26)65253-9

• 论文 • 上一篇    下一篇

纳米限域与疏水性离子液体双调控策略在低浓度CO2电还原中实现高甲醇选择性

张震a,b, 张香娅b, 张迈b, 杨逸飞b, 吴怡彤b, 张琳琳b,*(), 廖建军b,*(), 宋春风a,*()   

  1. a 天津大学环境科学与工程学院, 天津市室内空气环境质量控制重点实验室, 天津 330354
    b 海南大学环境科学与工程学院, 海南省农林环境过程与生态调控重点实验室, 海南海口 570228
  • 收稿日期:2026-03-26 接受日期:2026-06-26 出版日期:2027-01-02 发布日期:2026-10-30
  • 通讯作者: *电子信箱: chunfeng.song@tju.edu.cn (宋春风),
    liaojianjun008@163.com (廖建军),
    6962zhanglinlin@163.com (张琳琳).
  • 基金资助:
    海口市科技计划项目(2024-030);国家自然科学基金(52403087);海南省科技专项基金(ZDYF2024SHFZ115);海南省自然科学基金(525RC701);海南大学科研启动基金(kyqd(zr)22185)

Nano-confinement and hydrophobic ionic-liquid engineering for methanol-selective CO2 electroreduction from dilute streams

Zhen Zhanga,b, Xiangya Zhangb, Mai Zhangb, Yifei Yangb, Yitong Wub, Linlin Zhangb,*(), Jianjun Liaob,*(), Chunfeng Songa,*()   

  1. a Tianjin Key Laboratory of Indoor Air Environmental Quality Control, School of Environmental Science and Engineering, Tianjin University, Tianjin 330354, China
    b Key Laboratory of Agro-Forestry Environmental Processes and Ecological Regulation of Hainan Province, School of Environmental Science and Engineering, Hainan University, Haikou 570228, Hainan, China
  • Received:2026-03-26 Accepted:2026-06-26 Online:2027-01-02 Published:2026-10-30
  • Contact: *E-mail: chunfeng.song@tju.edu.cn (C. Song),
    liaojianjun008@163.com (J. Liao),
    6962zhanglinlin@163.com (L. Zhang).
  • Supported by:
    Haikou City Science and Technology Plan Project(2024-030);National Natural Science Foundation of China(52403087);Hainan Province Science and Technology Special Fund(ZDYF2024SHFZ115);Natural Science Foundation of Hainan Province(525RC701);Hainan University Research Start-up Fund (kyqd(zr)22185)

摘要:

电化学二氧化碳还原(CO2RR)被认为是将废弃CO2转化为燃料与化学品的重要路线, 尤其甲醇因可作为液体能源载体并具备碳一基础化工品的衔接优势而广受关注. 然而, 将CO2高选择性、高效率地还原为甲醇受限于反应动力学缓慢和析氢反应(HER)竞争, 并且这些问题在低浓度CO2进料下(如烟道气, 通常约10%‒15% CO2)会进一步加剧, 导致传质限制与界面CO2耗尽. 因此, 发展能够在低浓度CO2进料条件下实现CO2富集、抑制析氢反应, 并稳定关键中间体的催化策略, 对于推动CO2制甲醇的实际应用与碳资源可持续利用具有重要意义.

本文通过将非化学计量硒化铜(Cu2-xSe)纳米晶锚定于介孔含氮碳纳米纤维(CSNC)的多级孔骨架中, 利用孔道空间的纳米限域效应在稀释进料条件下将CO2有效富集于活性位周围, 提高CO2RR反应驱动力. 在此基础上, 引入疏水性离子液体1-乙基-3-甲基咪唑四氟硼酸盐([Emim][BF4])对CSNC孔道进行浸渍负载, 设计了CSNC/[Emim][BF4]电催化剂. 接触角测试表明, CSNC/[Emim][BF4]的接触角从CSNC的83.4°升至138.7°, 呈现近超疏水状态, 有效降低了水分子到达催化活性位的可及性, 从源头上削弱HER竞争. 同时, [Emim]+对CO2的高亲和力进一步强化局部CO2预富集, BF4-的低配位特性降低局部水活度, 实现CO2富集与HER抑制的双重协同. 实验结果表明在H型电解池中, CSNC/[Emim][BF4]在-0.52 V vs. RHE获得甲醇法拉第效率(FE)峰值为79.4%, 显著优于Cu2-xSe和CSNC, 且可维持> 70% FE长达48 h. 在气体扩散流动电池中, 该催化剂在-0.82 V vs. RHE下于纯CO2中甲醇FE达到78.8%, 电流密度在-1.4 V vs. RHE可达303 mA/cm2. 在模拟烟气的10%CO2进料条件下甲醇FE保持72.3%, 相较CSNC提升1.67倍, 相较于纯CO2工况FE仅下降8.2%, 且可稳定运行24 h. 机理研究方面, 进料切换实验表明CSNC/[Emim][BF4]以CO2或甲酸为碳源时产生大量甲醇, 而CO进料下仅生成痕量甲醇, 证明反应主要经由甲酸盐通路而非CO中间体路径进行. 原位拉曼光谱未检测到CO特征峰, 而在~1068 cm-1观察到CO32-峰, 表明限域微环境中碳酸盐积累降低了质子给体可用性. 原位红外光谱确认了吸附态甲酸盐中间体的生成. 密度泛函理论计算表明, CSNC/[Emim][BF4]表面H的吉布斯自由能高于Cu2-xSe和CSNC, 证明[Emim][BF4]通过提高HER能垒抑制析氢. 含氮位点通过Cu-N配位稳定COOH中间体, 促进其沿甲酸盐通路向甲醇深度加氢转化.

综上, 本工作以纳米限域与疏水调节协同策略有效构筑了CO2局部富集和抑制HER界面, 实现了稀薄CO2高选择性制甲醇, 阐明了CO2制甲醇的甲酸盐通路机制, 为面向低浓度CO2高效电催化剂设计和合成提供了新思路.

关键词: 低浓度CO2电还原, 离子液体, Cu2-xSe, 纳米限域, 甲醇

Abstract:

The electrocatalytic reduction of dilute carbon dioxide (CO2) to methanol faces dual challenges of sluggish reaction kinetics and the competing hydrogen evolution reaction (HER). This study presents a nanoconfined ionic liquid catalyst strategy, in which Cu2‒xSe nanocrystals are anchored as catalytic engines within mesoporous nitrogen-doped carbon nanofibers (CSNC), followed by impregnation with the ionic liquid [Emim][BF4] to modulate the reaction microenvironment. The multilevel pore structure of the catalyst enables local enrichment of CO2 through a nanoconfinement effect, while the homogeneous distribution of the ionic liquid combined with a hydrophobic interface collectively suppresses HER, thereby enhancing methanol selectivity. In an H-type cell with 0.5 mol/L KHCO3, CSNC/[Emim][BF4] achieves a peak methanol Faradaic efficiency (FE) of 79.4% at -0.52 V vs. RHE, sustaining > 70% FE over 48 h. In a flow cell with 1 mol/L KOH, FE reaches 78.8% under pure CO2 and 72.3% under 10% CO2 (simulating flue gas), 1.67 times higher than CSNC alone, with stable performance over 24 h. In situ spectroscopy and feedstock-switching experiments reveal N-coordination stabilizes *COOH intermediates, favoring methanol via the formate pathway. This strategy advances selective, stable CO2-to-methanol conversion from dilute streams, promoting sustainable carbon utilization and industrial flue gas valorization.

Key words: Low-concentration CO2 electroreduction, Ionic liquids, Cu2-xSe, Nano-confinement, Methanol