Unraveling the Electrical, Dielectric, and Electrocatalytic Properties of Bimetallic Cobalt-Based Metal–Organic Frameworks

Abstract

Bimetallic metal–organic frameworks (MOFs) offer unique synergistic properties and improved conductivity due to the integration of multiple metal components. However, their electrical and dielectric properties remain underexplored, and their charge transport mechanisms are not fully understood. This study investigates the electrical and dielectric properties of Mn-BTC (BTC = benzene-1,3,5-tricarboxylic acid), Co-BTC, and bimetallic Mn–Co BTC MOFs with varying Mn/Co ratios. Charge transport in these MOFs occurs via hopping at low frequencies, transitioning to lattice response at higher frequencies. While Mn incorporation typically reduces alternating current (AC) conductivity, the 1:2 Mn:Co MOF exhibits a unique conduction mechanism, enhancing AC conductivity by 25%. As electrocatalysts for oxygen evolution reaction (OER), the 1:2 Mn:Co MOF outperforms Mn-BTC, Co-BTC, and other Mn-Co BTC variants, achieving a lower overpotential (359 mV) and Tafel slope (71 mV dec⁻¹). The correlation between AC conductivity and electrocatalytic performance underscores the critical role of electrical properties in MOF functionality. This study highlights the potential of tailoring the electrical properties of bimetallic MOFs to optimize their electrocatalytic performance, offering valuable insights for future catalyst design.