Synthesis, Characterization, and Catalytic Performance of Heterogeneous Metal–Organic Framework-Derived Carbon-Based Electrocatalysts for Oxygen Evolution Reaction in Alkaline Media

Project Abstract

Sustainable energy conversion and storage technologies require efficient, durable, and cost-effective catalysts to accelerate the oxygen evolution reaction (OER) under alkaline conditions. This study reports a rational design and synthesis of heterogeneous metal–organic framework (MOF)-derived carbon-based electrocatalysts, engineered to maximize active site density, electrical conductivity, and structural robustness for enhanced OER performance in alkaline media. A series of ZIF-8/MIL-125-derived carbon matrices were selectively pyrolyzed under controlled atmospheres to generate hierarchically porous carbon frameworks embedded with uniformly distributed transition metal nanoparticles (Fe, Co, Ni) and nitrogen- and sulfur-doped heteroatoms, forming catalytically active M–N–C and M–S active sites. Systematic optimization of MOF precursor composition, pyrolysis temperature, dwell time, and post-synthesis activation with mild potassium hydroxide was conducted to tailor surface area, porosity, graphitization degree, and metal–support interactions. Comprehensive physicochemical characterization, including X-ray diffraction (XRD), Raman spectroscopy, transmission and scanning electron microscopy (TEM/SEM), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET) surface analysis, and inductively coupled plasma mass spectrometry (ICP-MS), confirmed the formation of highly graphitized carbon frameworks with multi-scale porosity and well-dispersed metallic nanoparticles encapsulated in nitrogen-rich carbon matrices. Electrochemical performance was evaluated in 1.0 M KOH to simulate alkaline conditions relevant to water-splitting devices. Linear sweep voltammetry (LSV) demonstrated a significant reduction in overpotential at 10 mA cm?2, while Tafel slope analysis indicated favorable kinetics for OER. Electrochemical impedance spectroscopy (EIS) and durability tests revealed low charge-transfer resistance, robust charge transport pathways, and superior long-term stability under continuous operation. Faradaic efficiency measurements confirmed efficient electron utilization with negligible parasitic reactions. Mechanistic investigations, supported by in situ spectroelectrochemical techniques and density functional theory (DFT) calculations, suggested a dual-active-site mechanism where M–N–C centers primarily facilitate OH? adsorption and electron transfer, while adjacent graphitic carbon domains provide rapid charge transport; synergistic interplay with M–S species further enhances O–O coupling steps. The study also explored the role of nitrogen functionalities (pyridinic, graphitic, and pyrrolic) and sulfur moieties in modulating charge density and adsorption energy for key OER intermediates (OH*, O*, O2*) in alkaline media. A comparative assessment against benchmark catalysts (IrO2, RuO2, and non-noble metal references) established competitive turnover frequencies and stability, underscoring the potential of MOF-derived carbon-based alloys as scalable, cost-effective alternatives for electrocatalysis. Finally, the work provides a practical synthesis–structure–property map linking MOF precursor design to catalytic performance, enabling targeted customization of multi-metal, heteroatom-doped carbon catalysts for efficient, durable OER in alkaline electrolyzers and integrated energy systems.

Project Overview

What This Project Is About

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The project looks at making and testing new carbon-based catalysts derived from metal–organic frameworks (materials built from metal nodes connected by organic linkers). These catalysts help the oxygen evolution reaction (OER), a key step in water splitting, especially in alkaline (basic) conditions. The goal is to find straightforward ways to create effective, durable catalysts that could replace more expensive materials.

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The Problem It Addresses

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Objectives of the Project

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1. Understand how to convert metal–organic frameworks into carbon-based electrocatalysts.
2. Characterize the structure, composition, and surface features of the catalysts.
3. Evaluate catalytic activity toward OER in alkaline solutions.
4. Assess durability and stability under operational conditions.
5. Identify relationships between synthesis steps and electrochemical performance.

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What You Will Do Step by Step

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1) Literature review on MOFs, carbon catalysts, and OER. 2) Synthesize MOF-derived carbon catalysts with controlled features. 3) Characterize materials using basic techniques (structure, surface area, composition). 4) Test OER activity in alkaline electrolyte and record performance metrics. 5) Analyze durability through repeated cycling and prolonged operation. 6) Correlate synthesis choices with performance results. 7) Compare with simple benchmarks. 8) Summarize findings and discuss practical implications.

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Expected Outcome

Anticipated results include a set of carbon-based catalysts with measurable OER activity and reasonable stability in alkaline media, plus an understanding of how synthesis affects performance. This could inform design guidelines for more affordable, durable OER catalysts.