Laser-Induced Synthesis of ZnO-Functionalized Graphene Electrodes from Imidazolate-Based MOFs for Electrochemical Applications

Zinc oxide (ZnO) nanoparticles possess attractive properties for electrochemical sensing, including high surface area, excellent electron mobility, and strong catalytic activity. However, conventional deposition methods often result in non-uniform distribution and weak adhesion, limiting sensor performance and reproducibility. In this work, we propose a top-down fabrication strategy for flexible, ZnO-functionalized electrodes by integrating imidazolate-based metal-organic framework (MOF) growth with laser-induced graphene (LIG) conversion. The process begins with surface activation of Kapton via KOH treatment, followed by layer-by-layer liquid-phase epitaxial deposition of ZIF-8 MOF to ensure uniform precursor loading. Controlled$\text{CO}_{2}$laser irradiation (15 W) simultaneously carbonizes the Kapton into a conductive 3D graphene framework and transforms the MOF layer into uniformly dispersed ZnO nanoparticles. The resulting hybrid electrode exhibits significantly enhanced electrochemical performance, achieving a peak current of ~1.8 mA in cyclic voltammetry using a$[\text{Fe}(\text{CN})_{6}]^{3-/^{4-}}$redox probe-over 2.5 times higher than electrodes derived from bare Kapton. The structure also demonstrates excellent mechanical flexibility and repeatable redox behavior across cycles. This scalable and template-directed approach offers a promising platform for next-generation flexible electrochemical sensors.