The thermal transformation of metal–organic frameworks (MOFs) generates a variety of nanostructured materials, including carbon-based materials, metal oxides, metal chalcogenides, metal phosphides and metal carbides. These derivatives of MOFs have characteristics such as high surface areas, permanent porosities and controllable functionalities that enable their good performance in sensing, gas storage, catalysis and energy-related applications. Although progress has been made to tune the morphologies of MOF-derived structures at the nanometre scale, it remains crucial to further our knowledge of the relationship between morphology and performance. In this Review, we summarize the synthetic strategies and optimized methods that enable control over the size, morphology, composition and structure of the derived nanomaterials. In addition, we compare the performance of materials prepared by the MOF-templated strategy and other synthetic methods. Our aim is to reveal the relationship between the morphology and the physico-chemical properties of MOF-derived nanostructures to optimize their performance for applications such as sensing, catalysis, and energy storage and conversion. Nanomaterials derived from metal–organic frameworks (MOFs) show good performance in sensing, gas storage, catalysis and energy-related applications. In this Review, the influence of the morphology of MOF-derived nanostructures on their performance is elucidated, and the opportunities in this field are discussed.

Nanomaterials derived from metal–organic frameworks

The rapidly expanding field of nonaqueous multivalent intercalation batteries offers a promising way to overcome safety, cost, and energy density limitations of state-of-the-art Li-ion battery technology. We present a critical and rigorous analysis of the increasing volume of multivalent battery research, focusing on a wide range of intercalation cathode materials and the mechanisms of multivalent ion insertion and migration within those frameworks. The present analysis covers a wide variety of material chemistries, including chalcogenides, oxides, and polyanions, highlighting merits and challenges of each class of materials as multivalent cathodes. The review underscores the overlap of experiments and theory, ranging from charting the design metrics useful for developing the next generation of MV-cathodes to targeted in-depth studies rationalizing complex experimental results. On the basis of our critical review of the literature, we provide suggestions for future multivalent cathode studies, including a...

Odyssey of Multivalent Cathode Materials: Open Questions and Future Challenges

Highly efficient electrocatalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) have been regarded as the core elements in a wide range of renewable energy technologies. Surface engineering of the electrocatalysts is one of the most popular strategies to improve their catalytic activity. Herein, we, for the first time, designed an advanced bi-functional electrocatalyst for the ORR and OER by simultaneously etching and doping a cobalt sulfides–graphene hybrid with NH3-plasma. The graphene supported Co9S8 nanoparticles were prepared (denoted as Co9S8/G) first, followed by the NH3-plasma treatment, which could not only lead to nitrogen doping into both Co9S8 and graphene, but also partially etch the surface of both Co9S8 and graphene. The heteroatom doping could efficiently tune the electronic properties of Co9S8 and graphene, and the surface etching could expose more active sites for electrocatalysis, which can contribute significantly to the enhanced electrocatalytic performance for ORR and OER. The electrochemical results revealed that the etched and N-doped Co9S8/G shows excellent ORR activity, which is close to that of the commercial Pt/C catalyst, and great OER activity. The strategy developed here provides a novel and efficient approach to prepare hybrid bi-functional electrocatalysts for ORR and OER.

Etched and doped Co9S8/graphene hybrid for oxygen electrocatalysis

Bifunctional electrocatalysts for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkaline electrolyte may improve the efficiency of overall water splitting. Nickel cobaltite (NiCo2O4) has been considered a promising electrode material for the OER. However, NiCo2O4 that can be used as an electrocatalyst in HER has not been studied yet. Herein, we report self-assembled hierarchical NiCo2O4 hollow microcuboids for overall water splitting including both the HER and OER reactions. The NiCo2O4 electrode shows excellent activity toward overall water splitting, with 10 mA cm−2 water-splitting current reached by applying just 1.65 V and 20 mA cm−2 by applying just 1.74 V across the two electrodes. The synthesis of NiCo2O4 microflowers confirms the importance of structural features for high-performance overall water splitting.

Hierarchical NiCo2 O4 Hollow Microcuboids as Bifunctional Electrocatalysts for Overall Water-Splitting.

Here we demonstrate the delicate design and construction of hierarchical Co9S8@ZnIn2S4 heterostructured cages as an efficient photocatalyst for hydrogen evolution with visible light. Two photoactive sulfide semiconductors are rationally integrated into a hierarchical hollow structure with strongly coupled heterogeneous shells and two-dimensional ultrathin subunits. The unique architecture can efficiently facilitate the separation and transfer of light-induced charges, offer large surface area, and expose rich active sites for photocatalytic redox reactions. Owing to the distinctive structural and compositional benefits, the hierarchical Co9S8@ZnIn2S4 hollow heterostructures without using any cocatalysts show remarkable activity with a hydrogen-producing rate of 6250 μmol h–1 g–1 and high stability for photocatalytic water splitting.

Formation of Hierarchical Co9S8@ZnIn2S4 Heterostructured Cages as an Efficient Photocatalyst for Hydrogen Evolution.

A new class of Co9 S8 @MoS2 core-shell structures formed on carbon nanofibers composed of cubic Co9 S8 as cores and layered MoS2 as shells is described. The core-shell design of these nanostructures allows the advantages of MoS2 and Co9 S8 to be combined, serving as a bifunctional electrocatalyst for H2 and O2 evolution.

When Cubic Cobalt Sulfide Meets Layered Molybdenum Disulfide: A Core–Shell System Toward Synergetic Electrocatalytic Water Splitting

MgVPO4F is proposed as a cathode material for rechargeable Mg ion batteries for the first time. First principles calculations were performed to study the electrochemical properties of MgVPO4F as a positive electrode material for rechargeable Mg ion batteries. Our theoretical study gives an expectation of good battery performance by MgVPO4F.

MgVPO4F as a one-dimensional Mg-ion conductor for Mg ion battery positive electrode: a first principles calculation

The electrochemical and Mg ion diffusion properties of tavorite-Mg0.5FeSO4F were studied by using first principles calculations. A discharge voltage of about 2.52 V versus Mg/Mg2+ corresponding to the redox couples of Fe3+/Fe2+ was predicted for tavorite-Mg0.5FeSO4F, and the experimental diffusion coefficient for the Mg-vacancy in Mg0.5−xFeSO4F is expected to be of the same order of magnitude as that of the Li-vacancy in Li1−xFeSO4F.

Bo Liu

Papers

When Cubic Cobalt Sulfide Meets Layered Molybdenum Disulfide: A Core–Shell System Toward Synergetic Electrocatalytic Water Splitting

MgVPO4F as a one-dimensional Mg-ion conductor for Mg ion battery positive electrode: a first principles calculation

Tavorite-FeSO4F as a potential cathode material for Mg ion batteries: a first principles calculation

MgVPO4F as a One‐Dimensional Mg‐Ion Conductor for Mg Ion Battery Positive Electrode: A First Principles Calculation.