催化学报 ›› 2026, Vol. 83: 388-399.DOI: 10.1016/S1872-2067(26)64979-0

• 论文 • 上一篇    下一篇

通过调节负载于MnO2上的银初始状态促进乙酸乙酯低温深度氧化: 银纳米颗粒和离子的内在作用

李建荣a,c,1, 张万鹏a,c,1, 肖航a,c, 田明姣b,*(), 何炽b,d,*()   

  1. a中国科学院城市环境研究所, 先进环境装备和污染防治技术全国重点实验室, 福建厦门 361021
    b西安交通大学环境科学与工程系, 陕西西安 710049
    c宁波(北仑)中科海西产业技术创新中心, 全省临港石化污染控制重点实验室, 宁波市城市环境污染与控制重点实验室, 浙江宁波 315021
    d中国科学院大学, 挥发性有机物污染控制材料与技术国家工程实验室, 北京 101408
  • 收稿日期:2025-08-14 接受日期:2025-11-12 出版日期:2026-04-18 发布日期:2026-03-04
  • 通讯作者: * 电子信箱: mingjiao.tian@xjtu.edu.cn (田明姣), chi_he@xjtu.edu.cn (何炽).
  • 作者简介:1共同第一作者.
  • 基金资助:
    福建省引导性项目(2024Y0052);宁波市科学技术局“科创甬江2035关键技术突破项目”(2024Z237);国家自然科学基金(22476157);国家自然科学基金(22276145)

Boosting ethyl acetate low-temperature deep oxidation by tuning the initial status of Ag over MnO2: Intrinsic role of Ag nanoparticles and ions

Jian-Rong Lia,c,1, Wan-Peng Zhanga,c,1, Hang Xiaoa,c, Mingjiao Tianb,*(), Chi Heb,d,*()   

  1. aState Key Laboratory of Advanced Environmental Technology, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, Fujian, China
    bDepartment of Environmental Science and Engineering, Xi’an Jiaotong University, Xi’an 710049, Shaanxi, China
    cZhejiang Key Laboratory of Pollution Control for Port-Petrochemical Industry & Ningbo Key Laboratory of Urban Environmental Pollution and Control, Ningbo (Beilun) Zhongke Haixi Industrial Technology Innovation Center, Ningbo 315021, Zhejiang, China
    dNational Engineering Laboratory for VOCs Pollution Control Material & Technology, University of Chinese Academy of Sciences, Beijing 101408, China
  • Received:2025-08-14 Accepted:2025-11-12 Online:2026-04-18 Published:2026-03-04
  • Contact: * E-mail: mingjiao.tian@xjtu.edu.cn (M. Tian), chi_he@xjtu.edu.cn (C. He).
  • About author:1Contributed equally to this work.
  • Supported by:
    guiding projects of Fujian Province(2024Y0052);Yongiiang 2035 Key Technology Breakthrough Programme of Ningbo(2024Z237);National Natural Science Foundation of China(22476157);National Natural Science Foundation of China(22276145)

摘要:

含氧挥发性有机化合物(OVOCs)主要由有机酯、酮、醇和醛类物质组成, 具有较高的大气反应活性, 对大气二次有机气溶胶和臭氧的生成具有显著贡献. 醇类和醛类在催化剂上的低温氧化已被广泛报道. 然而, 酮类和酯类(KEs, 如丙酮, 乙酸乙酯(EA))分子中C=O键对氧原子具有更强的吸引力, 易与O2在活性位点上发生竞争性吸附, 这对KEs的低温吸附和活化产生不利影响. 此外, KE分子中的C=O键能较高, 导致其活化和断裂需要更高的能量, 且不可避免地会产生多种有害副产物. KEs往往难以实现完全氧化且CO2产率较低. 因此, 设计能够实现KEs低温高效深度氧化的催化剂至关重要.
研究发现, 降低KEs的活化温度或加速限速步骤, 能够提高CO2选择性及KEs转化率, 这与催化剂表面O2解离产生的活性氧物种密切相关. KE分子活化与O2解离在催化剂活性位点上存在竞争关系. 因此, 为确保充足的活性氧物种参与KE分子及副产物的氧化反应, 必须调控催化剂中活性位点的类型与数量. 作为主要活性位点, 通过调控过渡金属氧化物与贵金属间的相互作用, 建立高活性的贵金属位点与氧空位, 对于增强催化剂对O2及KE分子的吸附和活化至关重要. 本文选择价格相对低廉的贵金属Ag与高活性的暴露(310)晶面的MnO2(310MnO2) 作为代表性催化剂组合. 分别将Ag离子和Ag纳米颗粒负载于310MnO2上, 最后通过高温煅烧合成了具有相似Ag纳米颗粒的催化剂Ag-IS/310MnO2和Ag-NP/310MnO2. 两个催化剂中形成了不同的活性位点, 两者对EA催化氧化也表现出显著的催化活性差异. 在150 °C Ag-NP/310MnO2的反应速率和TOFAg值分别是Ag-IS/310MnO2的4.3倍和4.1倍. 此外, Ag-NP/310MnO2催化剂的CO2选择性是Ag-IS/310MnO2催化剂的1.9倍. 原位红外光谱和理论计算等测试发现, EA在Ag位点上的吸附能力远强于O2, 而在氧空位处则呈现相反趋势. 在Ag-IS/310MnO2体系中, 由于EA的强烈竞争吸附, 仅有限O2分子被Ag位点吸附, 尤其在低温条件下难以有效解离, 最终导致其催化活性显著下降. Ag-NP/310MnO2中Ag位点(吸附EA)与氧空位(解离O2)的协同作用加速了O2的活化及后续EA的氧化过程. 大量活性氧物种进一步促进了乙酸分解(限速步骤), 从而赋予催化剂优异的高选择性和低温CO2生成能力.
综上, 本工作明确了贵金属和氧空位活性位对EA和O2的吸附活化能力, 实现了EA的低温催化氧化, 阐明了反应机制, 该策略为促进OVOCs深度净化提供了一种简单高效的途径, 展现出显著的环境意义.

关键词: 乙酸乙酯, 催化氧化, MnO2, Ag位点, 氧空位

Abstract:

Promoting activity while inhibiting hazardous byproduct formation remains a great challenge in oxygenated volatile organic compounds (OVOCs) purification. Here, we found that the low-temperature oxidation of ethyl acetate (EA) and the generation rate of CO2 were enhanced by controlling the initial Ag precursor (ions vs. nanoparticles) to engineer catalysts with distinct active site configurations. The reaction rate and TOFAg of Ag nanoparticles/310MnO2 (Ag-NP/310MnO2) are 4.3 and 4.1 times higher, respectively, than those of Ag ions/310MnO2 (Ag-IS/310MnO2) at 150 °C. And Ag-NP/310MnO2 further shows a 1.9-fold higher CO2 selectivity compared to that of Ag-IS/310MnO2. The adsorption ability of EA is much stronger than that of O2 at Ag site, while the opposite trend is observed at oxygen vacancy. The synergy between Ag site (EA adsorption) and oxygen vacancy (O2 dissociation) in Ag-NP/310MnO2 accelerates O2 activation and subsequent EA oxidation. Moreover, abundant active oxygen species (*O) promote the rate-limiting step of acetic acid decomposition, contributing to superior low-temperature CO2 selectivity. However, due to the fierce competition from EA, limited O2 is adsorbed at Ag site-occupied oxygen vacancy, which is difficult to dissociate especially at low temperature, leading to inferior activity of Ag-IS/310MnO2. This work provides a vital scientific basis for enhancing the low-temperature deep oxidation of OVOCs, showcasing remarkable environmental significance.

Key words: Ethyl acetate, Catalytic oxidation, MnO2, Ag site, Oxygen vacancy