Homologous metal-organic complexes reconstructed oxy-hydroxide heterostructures as efficient oxygen evolution...

It is imperative to investigate more cost-effective, long-lasting, efficient, and reliable non-noble metal electrocatalysts for the oxygen evolution reaction (OER) in hydrogen production via water splitting. Metal-organic complexes have been extensively researched and utilized for this purpose, yet their transformation in this process remains intriguing and underexplored. To enable a comprehensive comparison, we synthesized three types of metal-organic complexes with varying morphologies using the same raw material. Specifically, monocrystalline and lamella Fe-Co metal-organic frameworks (MOFs), along with Fe-Co metal-organic gels (MOGs), were created using p-Phthalic acid (PTA) as a ligand to facilitate the oxygen evolution reaction in a 1 M KOH solution. The overpotential (η₁₀) of MOF nanosheets (MOF-NSs) was 286 mV at 10 mA cm^-2 under 1 M KOH, while that of MOGs was 297 mV, and MOF single crystals (MOF-SCs) exhibited an overpotential (η₁₀) of 346 mV. Density-functional theory (DFT) calculations demonstrated that the formation of FeOOH/CoOOH heterostructures reduced adsorption energy barriers and accelerated the rate-determining step, thereby improving the overall catalytic performance of OER. Hence, the structural reconstruction approach can be leveraged to develop and fabricate high-performance OER electrocatalysts in energy and related applications.