Metal-organic frameworks (MOFs), also called porous coordination polymers, represent a class of crystalline porous materials built from organic linkers and metal ions/clusters. The unique features of MOFs, including structural diversity and tailorability as well as high surface area, etc., enable them to be a highly versatile platform for potential applications in many fields. Herein, an overview of recent developments achieved in MOF catalysis, including heterogeneous catalysis, photocatalysis, and eletrocatalysis over MOFs and MOF-based materials, is provided. The active sites involved in the catalysts are particularly emphasized. The challenges, future trends, and prospects associated with MOFs and their related materials for catalysis are also discussed.

Metal-Organic Frameworks as Platforms for Catalytic Applications.

Carbon-based nanomaterials have been widely used as catalysts or catalyst supports in the chemical industry or for energy or environmental applications due to their fascinating properties. High surface areas, tunable porosity, and functionalization are considered to be crucial to enhance the catalytic performance of carbon-based materials. Recently, the newly emerging metal–organic frameworks (MOFs) built from metal ions and polyfunctional organic ligands have proved to be promising self-sacrificing templates and precursors for preparing various carbon-based nanomaterials, benefiting from their high BET surface areas, abundant metal/organic species, large pore volumes, and extraordinary tunability of structures and compositions. In comparison with other carbon-based catalysts, MOF-derived carbon-based nanomaterials have great advantages in terms of tailorable morphologies and hierarchical porosity and easy functionalization with other heteroatoms and metal/metal oxides, which make them highly efficient as...

Development of MOF-Derived Carbon-Based Nanomaterials for Efficient Catalysis

Oxygen reduction reaction (ORR), oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) are three key reactions for the development of green and sustainable energy systems. Efficient electrocatalysts for these reactions are highly desired to lower their overpotentials and promote practical applications of related energy devices. Metal–organic frameworks (MOFs) have recently emerged as precursors to fabricate carbon-based electrocatalysts with high electrical conductivity and uniformly distributed active sites. In this review, the current progress of MOF-derived carbon-based materials for ORR/OER/HER electrocatalysis is presented. Materials design strategies of MOF-derived carbon-based materials are firstly summarized to show the rich possibilities of the morphology and composition of MOF-derived carbon-based materials. A wide range of applications based on these materials for ORR, OER, HER and multifunctional electrocatalysis are discussed, with an emphasis on the required features of MOF-derived carbon-based materials for the electrocatalysis of corresponding reactions. Finally, perspectives on the development of MOF-derived carbon-based materials for ORR, OER and HER electrocatalysis are provided.

MOF-derived electrocatalysts for oxygen reduction, oxygen evolution and hydrogen evolution reactions

Microbial fuel cells (MFCs) have been conceived and intensively studied as a promising technology to achieve sustainable wastewater treatment. However, doubts and debates arose in recent years regarding the technical and economic viability of this technology on a larger scale and in a real-world applications. Hence, it is time to think about and examine how to recalibrate this technology's role in a future paradigm of sustainable wastewater treatment. In the past years, many good ideas/approaches have been proposed and investigated for MFC application, but information is scattered. Various review papers were published on MFC configuration, substrates, electrode materials, separators and microbiology but there is lack of critical thinking and systematic analysis of MFC application niche in wastewater treatment. To systematically formulate a strategy of (potentially) practical MFC application and provide information to guide MFC development, this perspective has critically examined and discussed the problems and challenges for developing MFC technology, and identified a possible application niche whereby MFCs can be rationally incorporated into the treatment process. We propose integration of MFCs with other treatment technologies to form an MFC-centered treatment scheme based on thoroughly analyzing the challenges and opportunities, and discuss future efforts to be made for realizing sustainable wastewater treatment.

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Towards sustainable wastewater treatment by using microbial fuel cells-centered technologies

A review on heavy metal pollution, toxicity and remedial measures: Current trends and future perspectives

Microbial fuel cell (MFC) can generate electricity from organic substances based on anodic electrochemically active microorganisms and cathodic oxygen reduction reaction (ORR), thus exhibiting promising potential for harvesting electric energy from organic wastewater. The ORR performance is crucial to both power production efficiency and overall cost of MFC. A new type of metal-organic-framework-derived electrocatalysts containing cobalt and nitrogen-doped carbon (CoNC) is developed, which is effective to enhance activity, selectivity, and stability toward four-electron ORR in pH-neutral electrolyte. When glucose is used as the substrate, the maximum power density of 1665 mW m−2 is achieved for the optimized CoNC pyrolyzed at 900 °C, which is 39.8% higher than that of 1191 mW m−2 for commercial Pt/C catalyst in the single-chamber MFC. The improved performance of CoNC catalyst can be attributed to large surface area, microporous nature, and the involvement of nitrogen-coordinated cobalt species. These properties enable the efficient ORR by increasing the active sites and enhancing mass transfer of oxygen and protons at “water-flooding” three-phase boundary where ORR occurs. This work provides a proof-of-concept demonstration of a noble-metal-free high-efficiency and cost-effective ORR electrocatalyst for effective recovery of electricity from biomass materials and organic wastewater in MFC.

Enhanced Cathodic Oxygen Reduction and Power Production of Microbial Fuel Cell Based on Noble‐Metal‐Free Electrocatalyst Derived from Metal‐Organic Frameworks

Xiu-Heng Wang

Papers

Enhanced Cathodic Oxygen Reduction and Power Production of Microbial Fuel Cell Based on Noble‐Metal‐Free Electrocatalyst Derived from Metal‐Organic Frameworks

Switchable and simultaneous oil/water separation induced by prewetting with a superamphiphilic self-cleaning mesh

Rejection of heavy metals in acidic wastewater by a novel thin-film inorganic forward osmosis membrane

Temperature as a factor affecting transmembrane water flux in forward osmosis: Steady-state modeling and experimental validation

A novel stainless steel mesh/cobalt oxide hybrid electrode for efficient catalysis of oxygen reduction in a microbial fuel cell.