Greening the Processes of Metal–Organic Framework Synthesis and their Use in Sustainable Catalysis

Abstract

Given the shortage of sustainable resources and the increasingly serious environmental issues in recent decades, the demand for clean technologies and sustainable feedstocks is of great interest to researchers worldwide. With regard to the fields of energy saving and environmental remediation, the key point is the development of efficient catalysts, not only in terms of facile synthesis methods, but also the benign utilization of such catalysts. This work reviews the use of metal-organic frameworks (MOFs) and MOF-based materials in these fields. The definition of MOFs and MOF-based materials will be primarily introduced followed by a brief description of the characterization and stability of MOF-related materials under the applied conditions. The greening of MOF synthesis processes will then be discussed and catalogued by benign solvents and conditions and green precursors of MOFs. Furthermore, their suitable application in sustainable catalysis will be summarized, focusing on several typical atom-economic reactions, such as the direct introduction of H or O and C-C bond formation. Approaches towards reducing CO emission by MOF-based catalysts will be described with special emphasis on CO fixation and CO reduction. In addition, driven by the explosive growth of energy consumption in the last century, much research has gone into biomass, which represents a renewable alternative to fossil fuels and a sustainable carbon feedstock for chemical production. The advanced progress of biomass-related transformations is also illustrated herein. Fundamental insights into the nature of MOF-based materials as constitutionally easily recoverable heterogeneous catalysts and as supports for various active sites is thoroughly discussed. Finally, challenges facing the development of this field and the outlook for future research are presented.

Metal–Organic Frameworks-Based Catalysts for Biomass Processing

“…The presence of metal coordination centers in MOF frameworks can promote a wide range of organic reactions [35], in particular, relevant to biomass conversion. Additionally, thanks to the versatility of synthesis and their structural and compositional diversity MOFs have a reputation of eco-friendly alternatives for catalysis [36].…”

Recent Advances of MOFs and MOF‐Derived Materials in Thermally Driven Organic Transformations

“…Metal/metal compound composites derived from MOF pyrolysis are increasingly being employed in organic transformations . For example, Li's group reported a series of impressive studies . First, in 2015, they prepared a Co@C‐N (carbon‐nitrogen embedded cobalt NP) catalyst through the pyrolysis of a Co II ‐containing MOF (Co 9 (btc) 6 (tpt) 2 (H 2 O) 15 ; btc=1,3,5‐benzenetricarboxylate, tpt=2,4,6‐tris(4‐pyridyl)‐1,3,5‐triazine).…”

Restructuring Metal–Organic Frameworks to Nanoscale Bismuth Electrocatalysts for Highly Active and Selective CO2 Reduction to Formate

“…MOFs exhibit permanent porosity and the exposed metal sites render MOFs promising candidates for catalysis. [ 11 ] However, the same rigid porous structure that makes MOFs interesting materials in a range of applications, hinders their electrocatalytic stability and activity. Factors like the 3D geometry impeding the long‐range charge movement, the poor overlap of O atoms and metal d‐orbitals, and the redox‐inactive nature of many carboxylate‐based organic linkers determine the poor conductivity of MOFs.…”