Metal-organic framework (MOF) nanoparticles, also called porous coordination polymers, are a major part of nanomaterials science, and their role in catalysis is becoming central. The extraordinary variability and richness of their structures afford engineering synergies between the metal nodes, functional linkers, encapsulated substrates, or nanoparticles for multiple and selective heterogeneous interactions and activations in these MOF-based nanocatalysts. Pyrolysis of MOF-nanoparticle composites forms highly porous N- or P-doped graphitized MOF-derived nanomaterials that are increasingly used as efficient catalysts especially in electro- and photocatalysis. This review first briefly summarizes this background of MOF nanoparticle catalysis and then comprehensively reviews the fast-growing literature reported during the last years. The major parts are catalysis of organic and molecular reactions, electrocatalysis, photocatalysis, and views of prospects. Major challenges of our society are addressed using these well-defined heterogeneous catalysts in the fields of synthesis, energy, and environment. In spite of the many achievements, enormous progress is still necessary to improve our understanding of the processes involved beyond the proof-of-concept, particularly for selective methane oxidation, hydrogen production, water splitting, CO2 reduction to methanol, nitrogen fixation, and water depollution.

State of the Art and Prospects in Metal-Organic Framework (MOF)-Based and MOF-Derived Nanocatalysis.

Thanks to their remarkable mechanical, electrical, thermal, and barrier properties, graphene-based nanocomposites have been a hot area of research in the past decade. Because of their simple top-down synthesis, graphene oxide (GO) and reduced graphene oxide (rGO) have opened new possibilities for gas barrier, membrane separation, and stimuli-response characteristics in nanocomposites. Herein, we review the synthesis techniques most commonly used to produce these graphene derivatives, discuss how synthesis affects their key material properties, and highlight some examples of nanocomposites with unique and impressive properties. We specifically highlight their performances in separation applications, stimuli-responsive materials, anti-corrosion coatings, and energy storage. Finally, we discuss the outlook and remaining challenges in the field of practical industrial-scale production and use of graphene-derivative-based polymer nanocomposites.

Synthesis, properties, and applications of graphene oxide/reduced graphene oxide and their nanocomposites

With the increasing demands in energy consumption and increasing environmental concerns, it is of vital significance for developing renewable and clean energy sources to substitute traditional fossil fuels. As an outstanding candidate, hydrogen is recognized as a green energy carrier due to its high gravimetric energy density, zero carbon footprints, and earth-abundance. Currently, water splitting in alkaline electrolytes represents one of the most promising methods for sustainable hydrogen production, and the key challenge lies in the development of high-performance electrocatalysts for the hydrogen evolution reaction (HER). Given the rapid advances in the design and development of efficient catalysts towards the alkaline HER, especially capable transition metal (TM)-based materials, this review aims to summarise recent progress in the theoretical understanding of the alkaline HER and TM-based electrocatalysts. TM-based catalysts classified by their different anionic compositions (metals, alloys, oxides, hydroxides, sulfides, selenides, tellurides, nitrides, phosphides, carbides, and borides) are comprehensively showcased. Special attention is given to mainstream strategies that can improve the catalytic properties of each category, as well as the underlying structure–activity regimes. Additionally, the challenges for the future development of novel catalysts are also analyzed.

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Recent advances in transition metal-based electrocatalysts for alkaline hydrogen evolution

Oriented Transformation of Co-LDH into 2D/3D ZIF-67 to Achieve Co–N–C Hybrids for Efficient Overall Water Splitting

Electrocatalytic hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) are three typical reactions in energy conversion devices, such as water electrolyzers, metal–air batteries and fuel cells However, the sluggish kinetics of the HER/OER/ORR and their dependency on noble-metal-based catalysts (eg Pt, Ir and Ru) hinder the large-scale commercial applications of these devices Hence, the development of low-cost, efficient, stable and scalable electrocatalysts, especially bifunctional HER/OER or OER/ORR electrocatalysts that could simultaneously catalyze HER/OER or OER/ORR, is highly desired but full of great challenges To date, non-noble cobalt (Co)-based materials, including cobalt oxide, cobalt phosphides, cobalt chalcogenides (sulfide and selenides), Co-included layered double hydroxides, Co–N–C, Co-based single atoms and their composites, have been widely investigated as bifunctional electrocatalysts owing to their innate electrochemical capabilities and structural adjustability by mixing, doping or combining with other materials, such as carbon materials In this review, the fundamental mechanisms of the bifunctional electrocatalysis of ORR/OER and OER/HER are introduced and analyzed, and recent progress in the design, synthesis and emerging applications of Co-based materials as bifunctional electrocatalysts for ORR/OER or OER/HER in alkaline electrolytes are summarized and discussed Finally, the strategies and perspectives for designing novel highly efficient bifunctional cobalt-based electrocatalysts are analyzed This analysis is expected to highlight the challenges faced by bifunctional noble-metal-free electrocatalysts for the study and development of next-generation electrocatalysts for the HER/ORR/OER

Nanostructured Co-based bifunctional electrocatalysts for energy conversion and storage: current status and perspectives

The design and preparation of an excellent corrosion protection coating is still a grand challenge and is essential for large-scale practical application. Herein, a novel cationic reduced graphene oxide (denoted as RGO-ID+)-based epoxy coating was fabricated for corrosion protection. RGO-ID+ was synthesized by in situ synthesis and salification reaction, which is stable dispersion in water and epoxy latex, and the self-aligned RGO-ID+-reinforced cathodic electrophoretic epoxy nanocomposite coating (denoted as RGO-ID+ coating) at the surface of metal was prepared by electrodeposition. The self-alignment of RGO-ID+ in the coatings is mainly attributed to the electric field force. The significantly enhanced anticorrosion performance of RGO-ID+ coating is proved by a series of electrochemical measurements in different concentrated NaCl solutions and salt spray tests. This superior anticorrosion property benefits from the self-aligned RGO-ID+ nanosheets and the quaternary-N groups present in the RGO-ID+ nanoco...

Cationic Reduced Graphene Oxide as Self-Aligned Nanofiller in the Epoxy Nanocomposite Coating with Excellent Anticorrosive Performance and Its High Antibacterial Activity.

The development of outstanding noble-metal-free electrocatalysts for the hydrogen evolution reaction (HER) has attracted broad interest. Herein, a novel one-dimensional (1D) HER hybrid catalyst consisted of cobalt phosphide (CoP) and molybdenum carbide (Mo2C) nanoparticles wrapped by nitrogen-doped graphitic carbon (called CoP/Mo2C-NC) was successfully fabricated by a facile continuous-flow method and a simple two-step annealing process. During these processes, the successful synthesis of the MoO3 nanorods coated with cobalt zeolitic imidazolate frameworks (Co-ZIF-67) (Co-ZIF-67@MoO3) through the continuous-flow method plays a key role. The as-synthesized CoP/Mo2C-NC hybrid electrocatalyst exhibits a significantly enhanced HER electrocatalytic activity over the entire pH range relative to that of the control materials CoP, Mo2C-NC, and physically mixed CoP and Mo2C-NC. The outstanding HER catalytic performance is mainly due to the fact that the electron cloud transfers from Co to Mo in CoP/Mo2C-NC through...

One-Dimensional Porous Hybrid Structure of Mo2C-CoP Encapsulated in N-Doped Carbon Derived from MOF: An Efficient Electrocatalyst for Hydrogen Evolution Reaction over the Entire pH Range.

The exploration of highly efficient and stable bifunctional electrocatalysts for overall water splitting is currently of extreme interest for the efficient conversion of sustainable energy sources. Herein, we provide an earth-abundant, low-cost, and highly efficient bifunctional electrocatalyst composed of cobalt sulfide (Co9S8) and molybdenum carbide (Mo2C) nanoparticles anchored to metal–organic frameworks (MOFs)-derived nitrogen, sulfur-codoped graphitic carbon (Co9S8–NSC@Mo2C). The new composite mode of the electrocatalyst was realized through simple pyrolysis processes. The composite electrocatalyst shows outstanding hydrogen evolution reaction (HER) performance and excellent stability over the entire pH range. For example, it has a lower overpotential of 74, 89, and 121 mV with the Tafel slopes of 69.3, 86.7, and 106.4 mV dec–1 to achieve a current density of 10 mA cm–2 in 0.5 M H2SO4, 1.0 M KOH, and 1.0 M phosphate-buffered saline solutions, respectively. Moreover, it shows a small overpotential of...

Qiulan Zhou

Papers

Cationic Reduced Graphene Oxide as Self-Aligned Nanofiller in the Epoxy Nanocomposite Coating with Excellent Anticorrosive Performance and Its High Antibacterial Activity.

One-Dimensional Porous Hybrid Structure of Mo2C-CoP Encapsulated in N-Doped Carbon Derived from MOF: An Efficient Electrocatalyst for Hydrogen Evolution Reaction over the Entire pH Range.

Porous Co9S8/Nitrogen, Sulfur-Doped Carbon@Mo2C Dual Catalyst for Efficient Water Splitting.

Rational design of self-supported WC/Co3W3N/Co@NC yolk/shell nitrogen-doped porous carbon catalyst for highly efficient overall water splitting

Oxygen vacancy-rich ultrafine CoP/Co3O4 nanoparticles as high-efficiency trifunctional electrocatalyst