2D Metal Organic Framework‐Graphitic Carbon Nanocomposites as Precursors for High‐Performance O₂‐Evolution Electrocatalysts

Abstract

The development of effective and precious‐metal‐free electrocatalysts for the oxygen evolution reaction (OER) represents a major bottleneck to unlock a renewable energy scenario based on water splitting technologies. Materials uniting the electrical conductivity of conjugated graphitic nanomaterials with the chemical regularity of metal‐organic‐framework (MOF) crystals are promising precursors for such electrocatalysts. Nanoscale integration of these two materials is challenging. A new synthesis route is developed that integrates 2D MOF nanocrystals and graphitic carbon nanolamellae into layered composites. The graphitic carrier contributes excellent charge–transport properties, and the 2D macromolecular MOF precursor provides a suitable shuttle for introducing highly dispersed metal species. Furthermore their direct chemical environment can be controlled via selection of organic linker. Thermal decomposition of 2D cobalt tetrafluoro benzene‐dicarboxylate MOF nanocrystals within such composites enables the stabilization of cobalt oxyhydroxyfluoride nanoparticles on the graphitic carrier, which display an extraordinary activity for the OER in alkaline media, with low onset overpotential (310 mVRHE) and current densities >104 mA cm−2 μmolCo−1 at an operating overpotential of 450 mV, alongside excellent operational stability. The wide compositional array of MOFs makes this synthesis approach versatile toward advanced (electro)catalysts and other functional materials for applications from sensing to energy storage and conversion.

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

“…Since the chemical and the physical properties of the MOFs‐derived TM‐carbon‐based nanohybrids are highly dependent on the MOF precursors, it has been widely acknowledged that building MOF precursors with favorable composition, morphology, and surface structure is a prerequisite to enable these nanohybrids with satisfactory electrocatalytic activity . To this end, there has been much attention surrounding the dedicate design of MOF precursors . Currently, most work basically focus on the 3D MOF precursors owing to their high structural stability, large specific surface areas, and abundant pores .…”

“…Compared to 3D MOFs‐derived nanohybrids, 2D counterparts possess ultrathin feature and much higher surface area‐to‐volume ratio, ensuring the stronger electron transfer ability and higher utilization of the electrocatalytic active sites . For instance, Paik et al employed the 2D Ni‐based Prussian blue analogue nanoplates with thickness ranging from 40 to 50 nm as precursor to prepare carbon‐coated nickel phosphides nanoplates, bearing the abundant porosity and more accessible active sites, thus exhibiting the high OER catalytic activity with a low overpotential of 300 mV at a current density of 10 mA cm −2 in 1.0 m KOH .…”

The Role of Supported Atomically Distributed Metal Species in Electrochemistry and How to Create Them

“…Metal‐organic frameworks (MOF) are typical skeleton structures with a well‐defined and tunable metal environment. They can be used as a structural precursor, which is destroyed during the consecutive synthesis of the compound catalysts . Han et al.…”

“…They can be used as a structural precursor, which is destroyed during the consecutive synthesis of the compound catalysts. [88] Han et al synthesized hollow N-doped carbon spheres with a template-assisted pyrolysis method to obtain isolated single atomic sites on the carbon surface. [89] During the synthesis process, the SiO 2 template was dispersed in DMF solution before the addition of another monomer.…”

Structure-activity relationships in metal organic framework derived mesoporous nitrogen-doped carbon containing atomically dispersed iron sites for CO2 electrochemical reduction

“…[12,13] Nitrogen-doped carbon (hereafter denoted as NC) supported transition metal catalysts exhibit unique chemical and electrical properties, and are supposed to act as alternatives to expensive noble metal catalysts in electrocatalysis. [14,15] Interestingly, the catalytic activity and product selectivity to a large extent depend on the configuration of the transition metal in the carbon framework. For instance, iron nanoparticles anchored on NC supports were reported to mainly produce H2.…”