# Rapid Electrodeposition of Defect‐Tuned MOF Nanoarchitectures: Synergistic Unlocking Electrochemical Performance via Dual Modulation of Morphology and Electronic Structure

## TL;DR

This paper introduces a fast method to create MOF nanostructures that improve energy storage and oxygen evolution reaction performance through precise control of structure and electronic properties.

## Contribution

The novel approach combines rapid electrodeposition and defect engineering in MOF crystals to synergistically modulate morphology and electronic structure.

## Key findings

- Rapid electrodeposition produces ultrafine amorphous MOF(Co) nanostructures with enhanced electrochemical performance.
- Incorporation of nickel modulates the cobalt electronic environment, lowering the oxidation potential and improving stability.

## Abstract

Metal‐organic frameworks (MOFs) are increasingly used in energy storage and the oxygen evolution reaction (OER), where surfaces of MOF typically undergo structural transformation into metal (oxy)hydroxides as the true active sites. Synthesizing ultrasmall or amorphous MOF nanoparticles enables precise activation over the structural reconstruction. This work rapidly and precisely tailors ultrafine and order‐disorder structure in MOF‐74 crystals using ligands 2,5‐dihydroxyterephthalic acid (H4dobdc) and competitive salicylic acid (SA) via electrodeposition. Electrodeposition rapidly produces nanofragment (2∼3 nm)‐amorphous MOF(Co)‐SA1. The introduction of a secondary nickel center electronically modulates the primary cobalt in MOF(Co4Ni1)‐SA1. X‐ray absorption fine structure (XAFS) spectroscopy confirms this structure, which facilitates a structural reconstruction. This reconstruction, evidenced in the redox region by in situ Raman spectra, results in superior performance and long stability for both energy storage and OER applications. Theoretical calculations reveal a reduced reaction energy barrier (from 1.59 to 0.50 eV) correlated with a smaller crystal size, and Ni promotes electron transfer between Co and ligands and lowing the potential of redox of Co. Thus, rapid electrodeposition combined with precise defect engineering within MOF crystals effectively tailors the crystal size, coordination environment of metal centers, and subsequent electrochemical reconstruction, offering a viable strategy for enhanced electrochemical applications.

This work utilizes rapid electrodeposition and a competitive ligand to tailor crystal fragment/ amorphous MOF structures while Ni incorporation modulates the Co electronic environment. Their synergistic control over morphology and electronic structure accelerates reconstruction into active (oxy)hydroxides, lowers the Co3+/Co4+ oxidation potential, yielding improved energy‐storage and OER performance and offering a concise strategy for designing high‐efficiency MOF‐based electrocatalysts.