Metal Organic Frameworks Functionalized with Chiral Architectures for Spin-Selective Oxygen Evolution Reactions

Designing electrocatalysts that combine high activity, selectivity, and stability is critical for an efficient oxygen evolution reaction (OER). Previous studies show that modifying the OER catalysts, such as oxide, hydroxides, layered double hydroxides, etc., employing the chiral-induced spin selectivity (CISS) effect enhances the activity of the catalyst beyond its thermodynamic limit. However, to the best of our knowledge, inducing the CISS effect into a bimetallic metal organic framework (MOF) has not been studied yet. In this study, we report for the first time the incorporation of CISS in a NiFe-MOF-based thin-film catalyst using chiral naphthalene diimide (NDI) molecules that form helical supramolecular structures. Details of structural and spectroscopic analyses confirm the uniform Ni/Fe incorporation in the organic framework and successful chiral modification. The chiral R- and S-NiFe-MOF electrodes exhibit outstanding OER performance in 1 M KOH, requiring overpotential of only 290 mV at 10 mA cm–2 and Tafel slopes of 59 mV dec–1, markedly superior to the racemic analogue (325 mV, 76 mV dec–1). Oxygen evolution is measured quantitatively, and it reveals that the O2 evolution rate using the chiral catalyst is ∼1.5-fold higher than the achiral one. Significant reduction of the formation of the byproduct hydrogen peroxide while using chiral catalysts highlights the role of spin-polarized electron transfer that promotes the formation of triplet O2. Hence, this dual strategy of bimetallic synergy and chiral functionalization provides a robust platform for next-generation OER electrocatalysts for sustainable water-splitting and renewable-energy applications.