Synthesis and Optimization of Zeolitic Imidazolate Frameworks for the Oxygen Evolution Reaction

Abstract

Metal–organic frameworks/zeolitic imidazolate frameworks (MOFs/ZIFs) and their post‐synthesis modified nanostructures, such as oxides, hydroxides, and carbons have generated significant interest for electrocatalytic reactions. In this work, a high and durable oxygen evolution reaction (OER) performance directly from bimetallic Zn100−xCox‐ZIF samples is reported, without carrying out high‐temperature calcination and/or carbonization. ZIFs can be reproducibly and readily synthesized in large scale at ambient conditions. The bimetallic ZIFs show a systematic and gradually improved OER activity with increasing cobalt concentration. A further increase in OER activity is evidenced in ZIF‐67 polyhedrons with controlled particle size of <200 nm among samples of different sizes between 50 nm and 2 μm. Building on this, a significantly enhanced, >50 %, OER activity is obtained with ZIF‐67/carbon black, which shows a low overpotential of approximately 320 mV in 1.0 m KOH electrolyte. Such activity is comparable to or better than numerous MOF/ZIF‐derived electrocatalysts. The optimized ZIF‐67 sample also exhibits increased activity and durability over 24 h, which is attributed to an in situ developed active cobalt oxide/oxyhydroxide related nanophase.

Understanding the Effect of Second Metal on CoM (M = Ni, Cu, Zn) Metal–Organic Frameworks for Electrocatalytic Oxygen Evolution Reaction

“…[26][27][28][29][30][31][32] For example, Li et al reported that the CoZn bimetallic MOFs could exhibit OER activity with the overpotential of 320 mV at a current density of 10 mA cm −2 due to dimensionality and pore-geometry. [33] Furthermore, Bu et al reported that the CoNi bimetallic 2D-MOFs exhibited excellent OER activity with the overpotential of 240 mV at 10 mA cm −2 , thanks to the CoNi coupling effect and the unsaturated active sites. [34] However, although plenty of efficient Co MOFs-based bimetallic OER catalysts have been developed, to the best of our knowledge, the effect of different second metal on the OER catalytic performance of Co-based MOFs has not been systematically investigated.…”

MOF‐Derived Zinc‐Doped Ruthenium Oxide Hollow Nanorods as Highly Active and Stable Electrocatalysts for Oxygen Evolution in Acidic Media

“…In some synthesis process of electrocatalysts, like annealing, MOFs are usually used as precursors to obtained alloys, [14] doped oxides, [12a] heterojunctions, [15] metal‐nitrogen‐carbon system [9a,16] and other carbon based catalyst [17] . In some previous studies, the catalyst containing zinc element showed potential catalytic performance toward OER [18] . Meanwhile, the corresponding OER activity is also demonstrated for zinc‐air battery application [13] …”

Metal–Organic Framework‐Based Nanomaterials for Electrocatalytic Oxygen Evolution

“…The enhanced OER electrocatalytic performance is ascribed to the enlarged exposed active surface area, benefiting from the downsizing of MOF. [37] Similarly, Li et al recently used β-cyclodextrin (β-CD) as the modifier to regulate the size of MIL-53(Fe). The size of the synthesized MOFs can be well controlled by the introduction of different amounts of β-CD.…”