Rapidly increasing atmospheric CO2 concentrations threaten human society, the natural environment, and the synergy between the two. In order to ameliorate the CO2 problem, carbon capture and conversion techniques have been proposed. Metal–organic framework (MOF)-based materials, a relatively new class of porous materials with unique structural features, high surface areas, chemical tunability and stability, have been extensively studied with respect to their applicability to such techniques. Recently, it has become apparent that the CO2 capture capabilities of MOF-based materials significantly boost their potential toward CO2 conversion. Furthermore, MOF-based materials’ well-defined structures greatly facilitate the understanding of structure–property relationships and their roles in CO2 capture and conversion. In this review, we provide a comprehensive account of significant progress in the design and synthesis of MOF-based materials, including MOFs, MOF composites and MOF derivatives, and their application to carbon capture and conversion. Special emphases on the relationships between CO2 capture capacities of MOF-based materials and their catalytic CO2 conversion performances are discussed.

Carbon capture and conversion using metal–organic frameworks and MOF-based materials

More than 95% (in volume) of all of today’s chemical products are manufactured through catalytic processes, making research into more efficient catalytic materials a thrilling and very dynamic rese...

Metal–Organic Frameworks in Heterogeneous Catalysis: Recent Progress, New Trends, and Future Perspectives

Metal-organic frameworks (MOFs) have been widely recognized as one of the most fascinating classes of materials from science and engineering perspectives, benefiting from their high porosity and well-defined and tailored structures and components at the atomic level. Although their intrinsic micropores endow size-selective capability and high surface area, etc., the narrow pores limit their applications toward diffusion-control and large-size species involved processes. In recent years, the construction of hierarchically porous MOFs (HP-MOFs), MOF-based hierarchically porous composites, and MOF-based hierarchically porous derivatives has captured widespread interest to extend the applications of conventional MOF-based materials. In this Review, the recent advances in the design, synthesis, and functional applications of MOF-based hierarchically porous materials are summarized. Their structural characters toward various applications, including catalysis, gas storage and separation, air filtration, sewage treatment, sensing and energy storage, have been demonstrated with typical reports. The comparison of HP-MOFs with traditional porous materials (e.g., zeolite, porous silica, carbons, metal oxides, and polymers), subsisting challenges, as well as future directions in this research field, are also indicated.

Metal-Organic Framework-Based Hierarchically Porous Materials: Synthesis and Applications.

Ni-based metal organic frameworks (Ni-MOFs) with unique hierarchical hollow ball-in-ball nanostructure were synthesized by solvothermal reactions. After successive carbonization and oxidation treatments, hierarchical NiO/Ni nanocrystals covered with a graphene shell were obtained with the hollow ball-in-ball nanostructure intact. The resulting materials exhibited superior performance as the anode in lithium ion batteries (LIBs): they provide high reversible specific capacity (1144 mAh/g), excellent cyclability (nearly no capacity loss after 1000 cycles) and rate performance (805 mAh/g at 15 A/g). In addition, the hierarchical NiO/Ni/Graphene composites demonstrated promising performance as anode materials for sodium-ion batteries (SIBs). Such a superior lithium and sodium storage performance is derived from the well-designed hierarchical hollow ball-in-ball structure of NiO/Ni/Graphene composites, which not only mitigates the volume expansion of NiO during the cycles but also provides a continuous highly conductive graphene matrix to facilitate the fast charge transfer and form a stable SEI layer.

Metal Organic Frameworks Derived Hierarchical Hollow NiO/Ni/Graphene Composites for Lithium and Sodium Storage

Metal-organic framework-based heterogeneous catalysts for the conversion of C1 chemistry: CO, CO2 and CH4

It is of critical importance to design and fabricate highly active and stable catalysts for CO2 conversion. Herein, we synthesize a kind of novel porous heterobimetallic catalyst by manipulating the structural evolution of metal–organic framework (MOF) nanocrystals. The starting material, homometallic ZIF-8 nanoparticles, transforms in solution by cation exchange with Au3+ ions into heterobimetallic Au/Zn-MOF nanocages that favor the enhancement of active sites. With the use of regular hexahedral (RH) ZIF-8 and rhombic dodecahedral (RD) ZIF-8 nanoparticles as the templates, we obtain RH and RD Au/Zn-MOF nanocages with controllable shell thickness, respectively. The resulting Au/Zn-MOF nanocages are employed to catalyze the cycloaddition of CO2 and epoxides under mild reaction conditions. The excellent catalytic performance is demonstrated by high yields of 95–99% along with easy recyclability of the Au/Zn-MOF nanocages, which outperform most of the reported MOF-based catalysts and a homogeneous Au catalyst due to the synergetic effect of the two metallic components and the unique hollow structures. Impressively, these Au/Zn-MOF nanocages exhibit remarkable catalytic activity for CO2 conversion even at room temperature and atmospheric pressure. These nanomaterials thus hold great promise as catalysts for CO2 conversion in terms of facile preparation, abundant multiple active sites, and enhanced catalytic activity and stability.

Qilong Wu

Papers

Heterobimetallic metal–organic framework nanocages as highly efficient catalysts for CO2 conversion under mild conditions