Enhancing host-guest interactions through interfacial modulation of IRMOF-MXene hybrids: A detailed study on the significance of accessible functional groups in electrochemical detection

Metal-organic frameworks (MOFs) offer excellent structural tuneability that enables selective host-guest interactions, but integrating them with conductive substrates like Ti₃C₂T_x MXene can reduce accessibility to functional groups. This work empirically analyzes the influence of synthesis strategy on the electrochemical performance of amino-functionalized IRMOF 3-MXene hybrids for dopamine (DA) sensing, restricting their availability for DA interaction and reducing sensing efficiency. In contrast, the post-synthetic hybrid retains free –NH₂ groups, enabling effective DA preconcentration, which allows subsequent electron transfer to the conductive Ti₃C₂T_x. This results in enhanced electrocatalytic response, with a synergistic index of 1.12, high sensitivity (263.8 µA mM⁻¹ cm⁻²), and a low detection limit (56.4 nM) towards DA detection. The Schottky barrier formed at the MXene/IRMOF 3 interface modulates the charge transfer dynamics. Theoretical adsorption energy calculations further validate the experimental observations, highlighting the critical role of free and accessible functional groups in optimizing host-guest interactions for enhanced electrochemical performance.