基于金属-有机框架的甲烷选择性仿酶催化氧化的微环境调控  

Bioinspired microenvironment modulation of metal–organic framework-based catalysts for selective methane oxidation

作　　者：隋剑飞 高明亮 钱兵 刘成园 潘洋 孟征 袁大强 江海龙 Jianfei Sui;Ming-Liang Gao;Bing Qian;Chengyuan Liu;Yang Pan;Zheng Meng;Daqiang Yuan;Hai-Long Jiang(Department of Chemistry,University of Science and Technology of China,Hefei 230026,China;National Synchrotron Radiation Laboratory(NSRL),University of Science and Technology of China,Hefei 230029,China;State Key Laboratory of Structural Chemistry,Fujian Institute of Research on the Structure of Matter,Chinese Academy of Sciences,Fuzhou 350002,China)

机构地区：[1]Department of Chemistry,University of Science and Technology of China,Hefei 230026,China [2]National Synchrotron Radiation Laboratory(NSRL),University of Science and Technology of China,Hefei 230029,China [3]State Key Laboratory of Structural Chemistry,Fujian Institute of Research on the Structure of Matter,Chinese Academy of Sciences,Fuzhou 350002,China

出　　处：《Science Bulletin》2023年第17期1886-1893,共8页科学通报（英文版）

基　　金：supported by the National Key Research and Development Program of China(2021YFA1500402);the Strategic Priority Research Program of the Chinese Academy of Sciences(CAS)(XDB0450302);the National Natural Science Foundation of China(22161142001,U22A20401,and 22101269);International Partnership Program of CAS(123GJHZ2022028MI);the Fundamental Research Funds for the Central Universities(WK3450000007 and WK2060000038);the XAS supports from Beijing Synchrotron Radiation Facility(BSRF)。

摘　　要：甲烷选择性转化为甲醇,被认为是催化化学中的“圣杯”反应,其可生产高价值有机产品.然而,由于甲烷中的C-H键反应能垒很高及产物易发生过氧化反应,因此在温和条件下实现该反应仍是一个艰巨的挑战.在自然界中,甲烷营养菌等生物可以通过甲烷单加氧酶(MMOs)在温和条件下利用氧气将甲烷氧化为甲醇.近年来,虽有仿MMOs的甲烷选择性氧化制备甲醇的报道,但如何通过仿酶催化更好地实现这一反应仍然极具挑战性.本文通过将Fe-卟啉包覆到具有不同长烷基链的饱和单羧基脂肪酸修饰的金属有机骨架UiO-66中,构建了一系列仿生甲烷氧化催化剂.该催化剂在50℃下可以高效地实现催化甲烷转化为甲醇,并且可以通过Fe-卟啉周围疏水修饰的微环境来有效调节和促进对甲醇的选择性.锚定在UiO-66中Zr-oxo簇上的长链脂肪酸,不仅可以调节Fe位点的电子态,提高对甲烷的吸附,还可以调控Fe位点周围H_(2)O_(2)的浓度,减少过氧化反应,起到了类似于MMOs中的微环境调节作用,因此可以提高甲醇的选择性.Inspiration from natural enzymes enabling creationary catalyst design is appealing yet remains extremely challenging for selective methane(CH_(4))oxidation.This study presents the construction of a biomimetic catalyst platform for CH_(4)oxidation,which is constructed by incorporating Fe-porphyrin into a robust metal-organic framework,UiO-66,furnished with saturated monocarboxylic fatty acid bearing different long alkyl chains.The catalysts demonstrate the high efficiency in the CH_(4)to methanol(CH_(3)OH)conversion at 50℃.Moreover,the selectivity to CH_(3)OH can be effectively regulated and promoted through a fine-tuned microenvironment by hydrophobic modification around the Fe-porphyrin.The long-chain fatty acids anchored on the Zr-oxo cluster of UiO-66 can not only tune the electronic state of the Fe sites to improve CH_(4)adsorption,but also restrict the amount of H_(2)O_(2)around the Fe sites to reduce the overoxidation.This behavior resembles the microenvironment regulation in methane monooxygenase,resulting in high CH_(3)OH selectivity.

关 键 词：金属有机骨架 催化化学 长链脂肪酸 过氧化反应 电子态 甲烷氧化 温和条件 甲烷单加氧酶 

分 类 号：TQ223.121[化学工程—有机化工] TQ426