CO₂ Chemical Fixation into Value-Added Heterocycles Catalyzed by Non-Noble-Metal Metal-Organic Frameworks

ConspectusThe conversion of CO2 into high-value-added chemicals represents an effective strategy for CO2 utilization. However, due to the inherent thermodynamic stability of CO2, its conversion primarily relies on harsh conditions, such as high temperatures and pressures, along with the involvement of noble-metal catalysts. The effective transformation of CO2 under mild conditions remains a significant challenge. Therefore, the development of efficient catalysts is of critical importance. Metal-organic frameworks (MOFs) are a class of porous crystalline materials formed by the self-assembly of metal ions with multidentate organic ligands through coordination bonds. Its precise and customizable structure, combined with high surface area and the ease of functional modification, makes it an ideal platform for catalytic applications. These advantages facilitate the design of catalysts with high activity, selectivity, and stability through rational structural modulation, significantly enhancing CO2 conversion into value-added products under mild conditions. Moreover, this enables a deep understanding of the relationship between catalyst structure and performance. Therefore, summarizing research in this field and providing in-depth insight into the application of MOF-based catalysts for CO2 conversion is crucial for advancing future developments.In this Account, we will summarize and discuss recent advances on the structural design of non-noble metal MOFs and the mechanics in the catalytic conversion of CO2, especially emphasizing how to enhance the catalytic activity and selectivity by modulating Lewis acid and/or base sites. This Account begins by outlining the challenges associated with CO2 conversion. Subsequently, illustrating why MOFs are promising catalysts for CO2 utilization. Next, we present several specific strategies for constructing highly efficient MOF-based catalysts utilized in CO2 conversion: (1) To overcome the stability challenges associated with MOFs in CO2 conversion, we designed and synthesized a series of cluster-based MOFs. The high connectivity of the metal clusters imparts exceptional structural stability. (2) We highlighted a new strategy involving multiple Lewis acid sites to synergistically catalyze the highly efficient conversion of CO2 under mild conditions without the need for noble metals. (3) To obtain selective conversion of different reactions, we simultaneously introduced both Lewis acid and Lewis base active sites into the MOF structure. This approach significantly enhances catalytic efficiency while enabling a "switch-on/off" effect for different CO2 reactions. (4) Through the nanoconfinement effect, we achieved substrate size selectivity and reaction pathway modulation, significantly improving the efficiency of multicomponent CO2 reactions and reducing the formation of byproducts. Furthermore, we provided a comprehensive overview of the progress, summarized the advantages and limitations of current explorations, and discussed the potential outlook for future development. We believe that this Account will provide valuable insights into the emerging field of CO2 chemical fixation catalyzed by non-noble-metal MOFs.