物理化学学报 >> 2020, Vol. 36 >> Issue (3): 1907013.doi: 10.3866/PKU.WHXB201907013

所属专题: 光催化剂

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光催化甲烷转化研究进展

许振民,卞振锋*()   

  • 收稿日期:2019-07-01 录用日期:2019-08-29 发布日期:2019-09-02
  • 通讯作者: 卞振锋 E-mail:bianzhenfeng@shnu.edu.cn
  • 作者简介:卞振锋教授,博士生导师,2012年入选上海市“东方学者”特聘教授,2013年入选上海市曙光学者,2015年获得国家优秀青年科学基金。一直从事光催化净化环境研究,涉及光催化剂合成方法学、污染物降解机理和实际应用。至今以第一/通讯作者发表SCI论文30余篇,包括Environ. Sci. Technol.Nature Commun.J. Am. Chem. Soc.Angew. Chem. Int. Ed.等,论文他引近5000次,8篇为ESI论文;荣获2015年度上海市自然科学一等奖,排名第二;获2013–2014年度太阳能光化学与光催化研究领域优秀青年奖
  • 基金资助:
    国家自然科学基金(21876114);国家自然科学基金(21761142011);国家自然科学基金(51572174);上海市科委国际合作项目(19160712900);资源化学国际合作联合实验室(IJLRC)与上海市东方学者人才计划资助项目

Photocatalytic Methane Conversion

henmin Xu,Zhenfeng Bian*()   

  • Received:2019-07-01 Accepted:2019-08-29 Published:2019-09-02
  • Contact: Zhenfeng Bian E-mail:bianzhenfeng@shnu.edu.cn
  • Supported by:
    the National Natural Science Foundation of China(21876114);the National Natural Science Foundation of China(21761142011);the National Natural Science Foundation of China(51572174);Shanghai Government, China(19160712900);International Joint Laboratory on Resource Chemistry, China (IJLRC), and the Program for Professor of Special Appointment (Eastern Scholar) at Shanghai Institutions of Higher Learning, China

摘要:

甲烷催化转化为高附加值产物、实现甲烷高效利用,具有重要的研究意义及工业应用价值。长期以来,如何在较温和的条件下将甲烷转化为其它更有价值的有机衍生物,如醇、芳烃、长链烷烃和烯烃等,是催化、化学及化工领域的热点和难点课题之一。光催化反应由光能激发产生光生电子和空穴,参与到甲烷C―H键活化和自由基形成,这为低温甲烷转化提供新的途径,本文主要围绕甲烷氧化和偶联反应,总结了近年来光催化研究进展,并对如何进一步提高光催化性能提出展望。

关键词: 光催化, 甲烷转化, 氧化制甲醇, 无氧偶联, 氧化偶联

Abstract:

Methane is a promising energy source with vast reserves, and is considered one of the promising alternatives to nonrenewable petroleum resources because it can be converted into valuable hydrocarbon feedstocks and hydrogen through appropriate reactions. Recently, the conversion of CH4 into other high-value-added products has received increasing attention because of their sustainability for energy and the environment. However, methane has a tetrahedral geometry with four equivalent C―H bonds due to the sp3 hybridization of the central carbon atom, with a C―H bond length of 0.1087 nm and an H-C―H bond angle of 109.5°. The absence of a dipole moment and the small polarizability (2.84 × 10−40 C2·m2·J−1) imply that methane requires a high local electric field for polarization and for nucleophilic or electrophilic attack. Nevertheless, it is believed that an effective method to activate CH4 would be available, so that not only methanol, formaldehyde, and ethylene but also other industrially valuable raw materials can be obtained. On the other hand, the conversion of this combustible gas into the corresponding liquid fossil fuel proceeds via secondary chemical conversion, and it can greatly reduce transportation costs. From the economic viewpoint, this can still provide considerable benefits. Homogeneous catalysts have been reported to catalyze methane, but most of them operate at high pressures (2–7 MPa), or in strongly acidic media and at high temperatures (up to 500 K). Heterogeneous catalysts reported in the literature are also active only at high temperatures. Therefore, finding an efficient method to active methane has become a hot research topic. Photocatalysis technology is recognized as the optimal solution for the conversion of CH4 since solar energy is by far the largest exploitable resource of energy. In the past years, much effort has been undertaken for the conversion of CH4 under light at low temperature. In this regard, several photocatalysts, including silica-alumina-titania, silica-supported oxides, and ceria- and zeolite-based materials, have been developed. In photocatalytic methane conversion, the C―H bond can be selectively activated by adjusting the wavelength and intensity of the incident light and the oxidation capacity of the photocatalysts, thereby avoiding the formation of byproducts. This review summarizes a series of photocatalytic direct methane conversion systems developed in recent years, including methane oxidation and coupling processes. The effects of the catalyst composition and structure, oxidant, and electron transfer on the activation of the C―H bond of methane are detailed. Finally, future perspectives and challenges for the photocatalytic conversion of methane are discussed.

Key words: Photocatalysis, Methane conversion, Oxidation to methanol, Anaerobic coupling, Oxidative coupling

MSC2000: 

  • O643