Das Rajesh, Manna Surya Sekhar, Pathak Biswarup, Nagaraja C M
Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar, Punjab 140001, India.
Department of Chemistry, Indian Institute of Technology Indore, Indore, Madhya Pradesh 453552, India.
ACS Appl Mater Interfaces. 2022 Jul 15. doi: 10.1021/acsami.2c07969.
The sunlight-driven fixation of CO into valuable chemicals constitutes a promising approach toward environmental remediation and energy sustainability over traditional thermal-driven fixation. Consequently, in this article, we report a strategic design and utilization of Mg-centered porphyrin-based metal-organic framework (MOFs) having relevance to chlorophyll in green plants as a visible light-promoted highly recyclable catalyst for the effective fixation of CO into value-added cyclic carbonates under ambient conditions. Indeed, the Mg-centered porphyrin MOF showed good CO capture ability with a high heat of adsorption (44.5 kJ/mol) and superior catalytic activity under visible light irradiation in comparison to thermal-driven conditions. The excellent light-promoted catalytic activity of Mg-porphyrin MOF has been attributed to facile ligand-to-metal charge transfer transition from the photoexcited Mg-porphyrin unit (SBU) to the Zr cluster which in turn activates CO, thereby lowering the activation barrier for its cycloaddition with epoxides. The in-depth theoretical studies further unveiled the detailed mechanistic path of the light-promoted conversion of CO into high-value cyclic carbonates. This study represents a rare demonstration of sunlight-promoted sustainable fixation of CO, a greenhouse gas into value-added chemicals.
与传统热驱动固定相比，阳光驱动的将二氧化碳固定为有价值的化学品是一种很有前景的环境修复和能源可持续发展方法。因此，在本文中，我们报道了一种以镁为中心的卟啉基金属有机框架（MOF）的策略性设计和应用，该框架与绿色植物中的叶绿素相关，可作为可见光促进的高可回收催化剂，在环境条件下将二氧化碳有效地固定为增值环状碳酸酯。事实上，以镁为中心的卟啉MOF表现出良好的二氧化碳捕获能力，吸附热高（44.5 kJ/mol），与热驱动条件相比，在可见光照射下具有优异的催化活性。镁卟啉MOF优异的光促进催化活性归因于从光激发的镁卟啉单元（SBU）到锆簇的配体到金属的电荷转移跃迁，这反过来又激活了二氧化碳，从而降低了其与环氧化物环加成的活化能垒。深入的理论研究进一步揭示了光促进二氧化碳转化为高价值环状碳酸酯的详细机理路径。这项研究是将温室气体二氧化碳阳光促进可持续固定为增值化学品的罕见例证。
