催化学报

催化学报 ›› 2020, Vol. 41 ›› Issue (12): 1873-1883.DOI: 10.1016/S1872-2067(20)63641-5

• 论文 • 上一篇    下一篇

构筑耦合界面提高MnO2@Co3O4催化氧化甲苯性能

任泉明a, 莫胜鹏a, 樊洁a, 冯振涛a, 张明远a, 陈培榕a,b,c, 高加俭d, 付名利a,b,c, 陈礼敏a,b,c, 吴军良a,b,c, 叶代启a,b,c   

  1. a 华南理工大学环境与能源学院, 广东广州 510006, 中国;
    b 华南理工大学挥发性有机物污染治理技术与装备国家工程实验室, 广东广州 510006, 中国;
    c 华南理工大学广东省大气环境与污染控制重点实验室, 广东省环境风险防控与应急处置工程技术研究中心, 广东广州 510006, 中国;
    d 南洋理工大学化学与生物医药工程学院, 新加坡 637459, 新加坡
  • 收稿日期:2020-03-04 修回日期:2020-04-17 出版日期:2020-12-18 发布日期:2020-08-14
  • 通讯作者: 叶代启
  • 基金资助:
    国家重点研发计划（2017YFC0212805，2016YFC0204200）；国家自然科学基金（51878292，51878293，51678245）；广东省自然科学基金（2020A1515010929，2015B020236002，2014A030310431，2016A030311003）；广州市科技计划（201804020026）；广东省科技计划（2017B090901049）.

Enhancing catalytic toluene oxidation over MnO2@Co3O4 by constructing a coupled interface

Quanming Rena, Shengpeng Moa, Jie Fana, Zhentao Fenga, Mingyuan Zhanga, Peirong Chena,b,c, Jiajian Gaod, Mingli Fua,b,c, Limin Chena,b,c, Junliang Wua,b,c, Daiqi Yea,b,c   

  1. a School of Environment and Energy, South China University of Technology, Guangzhou 510006, Guangdong, China;
    b National Engineering Laboratory for VOCs Pollution Control Technology and Equipment, South China University of Technology, Guangzhou 510006, Guangdong, China;
    c Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control, Guangdong Provincial Engineering and Technology Research Centre for Environmental Risk Prevention and Emergency Disposal, South China University of Technology, Guangzhou 510006, Guangdong, China;
    d School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, Singapore 637459, Singapore
  • Received:2020-03-04 Revised:2020-04-17 Online:2020-12-18 Published:2020-08-14
  • Supported by:
    This work was supported by the National Key Research and Development Project of Research (2017YFC0212805, 2016YFC0204200, 2016YFC0204200, 2016YFC0204200), the National Natural Science Foundation of China (51878292, 51878293, 51678245), the Natural Science Foundation of Guangdong Province, China (2020A1515010929, 2015B020236002, 2014A030310431, 2016A030311003), the Science and Technology Project of Guangzhou City, China (201804020026), and the Science and Technology Program of Guangdong (2017B090901049).

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摘要： 挥发性有机化合物（VOCs）是大气主要污染物之一，它不仅危害人类健康，而且也危害环境.催化氧化是消除VOCs最有前景的方法之一.过渡金属氧化物由于其低成本、环境友好、高催化活性等优点，而越来越受到VOCs氧化领域的重视.一般认为，具有耦合界面的多组分金属氧化物比单组分金属氧化物表现出更好的催化性能.因此，本文在一维（1D）α-MnO2纳米线上原位生长ZIF衍生的Co3O4（α-MnO2@Co3O4）.由于α-MnO2和Co3O4之间耦合界面的协同效应，使得α-MnO2@Co3O4表现出优异的催化活性，甲苯转化率达到90%的反应温度（T90%）约为229℃，分别低于α-MnO2纳米线的（47℃）和热解ZIF-67产生的Co3O4-b的（28℃）.本文采用氢气程序升温还原（H2-TPR），氧气程序升温脱附（O2-TPD），X射线光电子能谱（XPS），原位漫反射红外光谱（in situ DRIFTS）等手段研究了具有α-MnO2和Co3O4耦合界面的α-MnO2@Co3O4催化剂表现更优异甲苯氧化性能的原因.
H2-TPR结果表明，相比于α-MnO2纳米线和热解ZIF-67产生的Co3O4-b，α-MnO2@Co3O4催化剂因具有耦合界面而表现出更好的氧流动性.O2-TPD结果表明，具有耦合界面的α-MnO2@Co3O4催化剂表面有更多的表面氧空位，从而使气相氧更容易活化为表面活性氧物种.XPS结果表明，具有耦合界面的α-MnO2@Co3O4催化剂表面有更多的活性氧物种，并且增强了Mn4+/Mn3+和Co2+/Co3+氧化还原对.原位漫反射红外结果表明，催化剂在180℃下吸附甲苯/N2 250min后，通入N2吹扫30min，然后将气氛切换为20% O2/N2，温度保持在180℃，反应进行250min时，α-MnO2表面吸附甲苯和苯甲醛的特征峰强度没有明显降低的趋势.相反，在反应进行50min时，α-MnO2@Co3O4表面吸附甲苯和苯甲醛的特征峰强度明显减弱，至250min时，这些特征峰几乎完全消失.这进一步表明，在α-MnO2@Co3O4表面，气相氧可能更容易活化为吸附氧物种，且甲苯在α-MnO2@Co3O4催化剂的可能催化反应路径如下：甲苯→苯甲酸→含氧官能团的烷烃→CO2和H2O，而更多的吸附氧物种有利于甲苯的催化氧化，且它们在催化氧化过程中起着重要的作用.另一方面，在催化反应中，阳离子的可逆价态转变（Mn3+ ? Mn4++e和Co2+ ? Co3++e）为活化氧分子提供了电子.因此，具有耦合界面的α-MnO2@Co3O4催化剂表现出更好的甲苯催化性能.此外，该制备方法可推广到其它一维MnO2材料，为开发具有实际意义的高性能催化剂提供了一种新的策略.

关键词: MnO2@Co3O4, 甲苯氧化, 协同作用, 耦合界面, 原位漫反射红外光谱

Abstract: Herein, a bottom-down design is presented to successfully fabricate ZIF-derived Co3O4, grown in situ on a one-dimensional (1D) α-MnO2 material, denoted as α-MnO2@Co3O4. The synergistic effect derived from the coupled interface constructed between α-MnO2 and Co3O4 is responsible for the enhanced catalytic activity. The resultant α-MnO2@Co3O4 catalyst exhibits excellent catalytic activity at a T90% (temperature required to achieve a toluene conversion of 90%) of approximately 229 ℃, which is 47 and 28 ℃ lower than those of the pure α-MnO2 nanowire and Co3O4-b obtained via pyrolysis of ZIF-67, respectively. This activity is attributed to the increase in the number of surface-adsorbed oxygen species, which accelerate the oxygen mobility and enhance the redox pairs of Mn4+/Mn3+ and Co2+/Co3+. Moreover, the result of in situ diffuse reflectance infrared Fourier transform spectroscopy suggests that the gaseous oxygen could be more easily activated to adsorbed oxygen species on the surface of α-MnO2@Co3O4 than on that of α-MnO2. The catalytic reaction route of toluene oxidation over the α-MnO2@Co3O4 catalyst is as follows:toluene → benzoate species → alkanes containing oxygen functional group → CO2 and H2O. In addition, the α-MnO2@Co3O4 catalyst shows excellent stability and good water resistance for toluene oxidation. Furthermore, the preparation method can be extended to other 1D MnO2 materials. A new strategy for the development of high-performance catalysts of practical significance is provided.

Key words: MnO2@Co3O4, Toluene oxidation, Synergistic effect, Coupled interface, In situ DRIFTS