Hollow Functional Materials Derived from Metal–Organic Frameworks: Synthetic Strategies, Conversion Mechanisms, and Electrochemical Applications

Abstract

Hollow materials derived from metal-organic frameworks (MOFs), by virtue of their controllable configuration, composition, porosity, and specific surface area, have shown fascinating physicochemical properties and widespread applications, especially in electrochemical energy storage and conversion. Here, the recent advances in the controllable synthesis are discussed, mainly focusing on the conversion mechanisms from MOFs to hollow-structured materials. The synthetic strategies of MOF-derived hollow-structured materials are broadly sorted into two categories: the controllable synthesis of hollow MOFs and subsequent pyrolysis into functional materials, and the controllable conversion of solid MOFs with predesigned composition and morphology into hollow structures. Based on the formation processes of hollow MOFs and the conversion processes of solid MOFs, the synthetic strategies are further conceptually grouped into six categories: template-mediated assembly, stepped dissolution-regrowth, selective chemical etching, interfacial ion exchange, heterogeneous construction, and self-catalytic pyrolysis. By analyzing and discussing fourteen types of reaction processes in detail, a systematic mechanism of conversion from MOFs to hollow-structured materials is exhibited. Afterward, the applications of these hollow structures as electrode materials for lithium-ion batteries, hybrid supercapacitors, and electrocatalysis are presented. Finally, an outlook on the emergent challenges and future developments in terms of their controllable fabrications and electrochemical applications is further discussed.

Cross‐Linked Surface Engineering to Improve Iron Porphyrin Catalytic Activity

“…Nanoreactors, with controllable elaborate microstructure, ideal local voids, and hollow nanostructures, show excellent performance on catalysis, supercapacitors, chemical sensors, and biomedicine. [ 1–5 ] Particularly, for catalysis, the well‐designed hollow nanomaterials do not only provide platform for the specific catalytic reaction but also can be used as model to reveal the mechanism of nano‐catalytic reaction. Generally, metal organic frameworks (MOFs) have shown a lot of advantages as an important type of catalyst and have emerged as promising platforms for diverse applications.…”

Redox Tuning in Crystalline and Electronic Structure of Bimetal–Organic Frameworks Derived Cobalt/Nickel Boride/Sulfide for Boosted Faradaic Capacitance

“…[11][12][13][14][15] In sharp contrast to the inorganic electrode materials, their diverse topology structure, tunable porosity, and abundant metal ions allow them to be a promising energy storage material. [16,17] However, the poor conductivity and lack of structural stability of pristine MOFs remain the critical limitations for practical applications in energy storage devices. [18,19] Except for MOFs-derived nanocarbons or metal compounds, [15,20,21] hybridizing MOFs with conductive polymers or carbon substrates is an additional productive tactic to improve the conductivity and stability, which can accelerate the electron transfer and reduce the inner resistance during the electrochemical reactions, even though the loading of active MOF species is lowered by the existence of conducting materials in a hybrid composition.…”

Recent Approaches to Design Electrocatalysts Based on Metal–Organic Frameworks and Their Derivatives

“…Alternatively, the pyrolysis of MOFs to MOFs derivatives offers an opportunity for producing conductive carbon materials and keeping the high porosity of MOFs precursor, facilitating the charge transfer from the electrode to catalysts surface and expose the active sites as much as possible . The catalytic hetero‐atoms can be introduced onto the electrode by well‐chosen of target MOFs and further improve the electrical, chemical and functional properties of the carbon materials by the pyrolytic process.…”