物理化学学报 >> 2025, Vol. 41 >> Issue (4): 100038.doi: 10.3866/PKU.WHXB202408015

论文 上一篇    

光增强CuOx/TiO2催化丙烯氧气直接环氧化反应

吕卓岩1,2, 丁杨铭1, 康磊磊1,*(), 李林1, 刘晓艳1,*(), 王爱琴1, 张涛1   

  1. 1 中国科学院大连化学物理研究所, 中国科学院航天催化材料重点实验室, 能源材料化学协同创新中心, 辽宁 大连 116023
    2 中国科学院大学, 北京 100049
  • 收稿日期:2024-08-27 修回日期:2024-09-25 录用日期:2024-10-02 发布日期:2024-12-28
  • 通讯作者: Email: xyliu2003@dicp.ac.cn; Tel.: +86-411-84379416 (刘晓艳)leikang@dicp.ac.cn (康磊磊)
  • 基金资助:
    国家自然科学基金委“单原子催化”基础科学中心项目(22388102); 中央高校基本科研业务费专项资金(20720220009); 中国科学院洁净能源创新研究院合作基金(DNL202002); 辽宁省兴辽英才计划(XLYC2007070); 中国科学院B类先导专项(XDB0540000)

Light-Enhanced Direct Epoxidation of Propylene by Molecular Oxygen over CuOx/TiO2 Catalyst

Zhuoyan Lv1,2, Yangming Ding1, Leilei Kang1,*(), Lin Li1, Xiao Yan Liu1,*(), Aiqin Wang1, Tao Zhang1   

  1. 1 CAS Key Laboratory of Science and Technology on Applied Catalysis, iChEM, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning Province, China
    2 University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2024-08-27 Revised:2024-09-25 Accepted:2024-10-02 Published:2024-12-28
  • Contact: Email: xyliu2003@dicp.ac.cn; Tel.: +86-411-84379416 (Xiao Yan Liu)leikang@dicp.ac.cn (Leilei Kang)
  • Supported by:
    the NSFC Center for Single-Atom Catalysis(22388102); the Fundamental Research Funds for the Central Universities(20720220009); the DNL Cooperation Fund, CAS(DNL202002); the DNL Cooperation Fund, CAS(XLYC2007070); the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB0540000)

摘要:

丙烯氧气直接环氧化(DEP)反应是合成环氧丙烷(PO)一种理想途径,但这一过程极具挑战性。本工作发现通过光热协同催化作用,在CuOx/TiO2催化剂上可以提升PO的生成速率和选择性。在180 ℃时,引入光照可使PO的生成速率提高20倍以上(从8.2增加到180.6 μmol·g−1·h−1),同时选择性提高了3倍以上(从8%增加到27%),打破了半导体在DEP反应中活性和选择性极低的传统认知。动力学研究结果表明,光照可显著降低PO生成的活化能(从95降至40 kJ·mol−1)。采用原位电子顺磁共振(EPR)、X射线光电子能谱(XPS)、拉曼光谱和漫反射红外傅里叶变换光谱(DRIFTS)技术,对铜氧化物物种的价态进行了动态表征,确定了氧气分子活化中间体的构型,首次捕捉到促进PO生成的活性氧物种。光生电子能够促进Cu+活性物种的形成以及μ侧过氧化二铜结构的产生,削弱O―O键,从而提高PO的生成速率和选择性。本工作为设计用于DEP反应的半导体光催化剂奠定良好的基础。

关键词: 光热催化, 铜氧化钛, 选择氧化, 丙烯直接环氧化, 氧气活化

Abstract:

Direct epoxidation of propylene (DEP) by molecular oxygen is an ideal way to synthesize propylene oxide (PO), yet it remains quite challenging. We demonstrated here that the PO formation rate and selectivity could be enhanced simultaneously through photo-thermo-catalysis over the Cu/TiO2 catalyst. At 180 ℃, by introducing light, the PO formation rate increased more than 20-fold (from 8.2 to 180.6 μmol∙g−1∙h−1) and the corresponding selectivity improved more than 3-fold (from 8% to 27%), breaking the traditional perception that the semiconductors exhibit very low reactivity for this reaction. Kinetic study results showed that the apparent activation energy for PO formation could sharply decrease under light irradiation (from 95 to 40 kJ∙mol−1). In situ electron paramagnetic resonance (EPR), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) were applied to characterize the dynamics of the valence state of the copper oxide species and the activation intermediates of molecular oxygen. Evidence for the activation of oxygen, which could direct to the PO formation pathway, was captured. The light-driven electrons could promote the formation of active Cu+, which could form the side-on μ-peroxo Cu(Ⅱ)2 structure, weaken the O―O bond, and improve the PO formation rate and selectivity. This work paves a new way for designing semiconductor-supported photocatalysts for DEP reactions with molecular oxygen.

Key words: Photo-thermo-catalysis, Cu/TiO2, Selective oxidation, Direct propylene epoxidation, Oxygen activation