化学学报 ›› 2019, Vol. 77 ›› Issue (3): 242-252.DOI: 10.6023/A18100440 上一篇    下一篇

综述

卟啉金属-有机框架在二氧化碳捕获与转化上的应用研究

陈之尧, 刘捷威, 崔浩, 张利, 苏成勇   

  1. 中山大学化学学院 广州 510275
  • 收稿日期:2018-10-20 出版日期:2019-03-15 发布日期:2018-12-27
  • 通讯作者: 张利, 苏成勇 E-mail:zhli99@mail.sysu.edu.cn;cesscy@mail.sysu.edu.cn
  • 作者简介:张利,中山大学化学学院教授.研究方向为金属有机化学与催化,将具有优异催化性能的金属有机均相催化剂(主要包括铜盐、双核铑羧酸配合物和铂族金属卟啉)引入到金属-有机多孔材料中,发展新型的异相催化剂,研究它们在有机反应中的催化性能和选择性(如化学、区域和立体选择性).目前重点开展的课题是"卟啉金属-有机框架的设计、合成以及催化性能研究",其中催化反应集中在卡宾/氮宾转移反应和CO2捕获与转化反应;苏成勇,中山大学化学学院教授.研究方向为配位超分子化学与材料,主要从事环境与清洁能源相关性金属-有机新材料的研究,包括(1)超分子组装:金属-有机容器与反应器(MOCs),金属-有机框架(MOFs)和金属-有机凝胶(MOGs)的可控合成与构效关系;(2)超分子催化:微纳限域配位空间的识别、响应与催化行为;(3)超分子材料:吸附、分离、光电、动态金属-有机分子固体材料.
  • 基金资助:

    项目受国家自然科学基金(Nos.21773314,21720102007,21821003,21890380)、广东省自然科学基金(No.S2013030013474)、广州市科技计划项目(Nos.201707010168,201504010031)和中央高校基本科研业务费专项基金(Nos.161gjc68,171gjc12)资助.

Applications of Porphyrin Metal-Organic Frameworks in CO2 Capture and Conversion

Chen Zhiyao, Liu Jiewei, Cui Hao, Zhang Li, Su Chengyong   

  1. School of Chemistry, Sun Yat-Sen University, Guangzhou 510275
  • Received:2018-10-20 Online:2019-03-15 Published:2018-12-27
  • Supported by:

    Project supported by the National Natural Science Foundation of China (Nos. 21773314, 21720102007, 21821003, 21890380), the Natural Science Foundation of Guangdong Province (No. S2013030013474), the Science and Technology Planning Project of Guangzhou (Nos. 201707010168, 201504010031) and the Fundamental Research Funds for the Central Universities (Nos. 16lgjc68, 17lgjc12).

近几十年来,气候变暖、海平面上升等全球性气候问题日益严重,对人们赖以生存的自然环境造成了巨大的威胁.为了缓解并最终解决温室效应,多年来人们一直着手研究以二氧化碳(CO2)为主的温室气体的处理方法.CO2捕获和转化是一项新的技术,将捕获得到的CO2直接转化成甲酸、甲醇、甲烷等小分子有机物或药物中间体等高附加值的化合物.卟啉金属-有机框架(Porphyrin Metal-Organic Frameworks,PMOFs)是一种基于卟啉配体和金属节点的多孔配位框架材料.卟啉配体具有良好热稳定性、化学稳定性以及优异独特的光学性能,结合MOFs框架的多孔性带来的对CO2等气体分子的良好吸附性,使得PMOFs在CO2捕获与转化上具有巨大的潜力.首先,介绍了PMOFs合成中常用的构筑策略,包括拓扑导向、柱层策略以及金属-有机笼策略.然后,根据次级结构基元对常见的PMOFs结构进行系统分类,包括基于低价态金属离子、桨轮状M2(COO)4、金属-氧无限长链和硬酸金属-氧簇四类,叙述了各类PMOFs的结构特性和稳定性.随后,通过一些代表性的实例分类总结了PMOFs在CO2捕获与转化上的应用,包括CO2的捕获、环加成反应、光催化反应和电催化反应.最后,总结了PMOFs在四大类应用中具有的优势与挑战,并展望了PMOFs在CO2捕获与转化中的机遇和发展前景.

关键词: 卟啉金属-有机框架, CO2捕获与转化, CO2环加成反应, CO2光还原, CO2电还原

The worldwide climate issues such as the global warming and the sea level rising are becoming serious. In order to relieve the stress of environment, a lot of attempts have been made to reduce the emission of CO2, which is the main component of greenhouse gases. CO2 capture and conversion (C3) is an emerging technology, which directly converts the captured CO2 into high value-added compounds or fuels such as formic acid, methanol and methane. Porphyrin metal-organic frameworks (PMOFs) are based on porphyrin or metalloporphyrin ligands and metal nodes. The combination of excellent thermal/chemical stability, strong absorption of visible light and long lifetime of excited state, and high CO2 capture capacity paves the way for the applications of PMOFs in C3. In this review, we have firstly introduced the synthesis strategies of PMOFs, which are guided by framework topology, pillar-layer and metal-organic cage (MOC). With the good control of the pore sizes and thermal/chemical stability, the catalytic performances of PMOFs can be easily tuned:PMOFs that are prepared via the pillar-layer and MOC strategies are of relatively lower stability, and the ones that are guided by framework topology are of higher stability. Next, we have classified the types of PMOFs according to the secondary building units (SBUs). There are four types of PMOFs, and the SBUs include (1) the low-valence metal ions such as Cu2+ and Cd2+; (2) the paddle-wheel M2(COO)4 (M=Cu2+, Zn2+) units; (3) the infinite metal (such as Al3+, Ga3+ and In3+) oxide chains; (4) the hard metal (such as Cr3+, Fe3+, Ti4+, Zr4+, Hf4+, and rare earth metals) oxide clusters. The structure characters and stability have been described afterwards. The coordination bonds in the first and second types of SBUs are relatively weak. For comparison, most of the PMOFs based on the infinite metal oxide chains and hard metal oxide cluster exhibit high thermal/chemical stabilities, which could be used for practical applications towards C3. Then, we have summarized the recent works about applications of PMOFs in C3, which are divided into four parts, including the selective capture of CO2, organic transformations with CO2, CO2 photoreduction and CO2 electroreduction. Selective capture of CO2 from a mixture of gases is one of the most important applications, considering that less energy and lower temperatures/pressures are required. Through the catalytic cycloaddition reaction of CO2 and epoxides, the important products of cyclic carbonates can be produced. Some of the catalytic reactions can be carried out at 0.1 MPa and room temperature with high yields. With the assistance of environmentally friendly visible light, CO2 can be photoreduced into fuels such as formate ion, methanol and methane. In addition, two typical examples of CO2 electroreduction have been discussed in this review. Through the process of photoreduction and electroreduction, clean energies such as solar light and electricity can be employed to help transfer the green gas CO2 into fuels. At the end, we have discussed the merits and challenges of PMOFs in the applications of C3. Selective adsorption of CO2 from other gases, especially NOx, SOx and other flue gases, is highly required. The efficiency of the catalytic cycloaddition reaction should be further improved, especially cutting down the reaction time. Reaction efficiency and product selectivity of photoreduction and electroreduction should be improved. Photoelectrocatalytic reduction of CO2, which combines both advantages of photoreduction and electroreduction, should be a hot topic in the future. The ideal system should include both a photoanode for water oxidation and a photocathode for CO2 reduction that are linked by a wire without external applied bias, achieving the dream of artificial photosynthesis.

Key words: porphyrin metal-organic framework, CO2 capture and conversion, CO2 cycloaddition reaction, CO2 photoreduction, CO2 electroreduction