Graphene–ZnO–β‐Cyclodextrin Nanohybrid: Synthesis, Photocatalytic, and Antimicrobial Properties

ABSTRACT This study reports the synthesis and characterization of a novel GO/ZnO/β‐CD nanocomposite for efficient photocatalytic degradation of methylene blue (MB) dye and antibacterial applications. The nanocomposite was synthesized via a facile hydrothermal method and extensively characterized through FTIR, XRD, SEM, TEM, EDX, and BET analyses, confirming successful integration of all components with characteristic functional groups preserved. XRD patterns revealed the hexagonal wurtzite crystalline structure of ZnO nanoparticles with average crystallite size of 27–32 nm, while SEM and TEM imaging demonstrated hierarchical morphology with uniformly distributed ZnO nanoparticles (15–30 nm) anchored onto crumpled GO. EDX analysis confirmed optimal elemental composition of 65.8 wt% Zn, 22.1 wt% O, and 11.21 wt% C. The GO/ZnO/β‐CD nanocomposite exhibited superior photocatalytic performance, achieving 99% MB degradation within 60 min under UV irradiation at optimal conditions (MB concentration: 15 ppm, catalyst loading: 0.03 g/20 mL), significantly outperforming GO/ZnO (97%) and GO (95%) alone. Kinetic analysis revealed the degradation process follows pseudo‐second‐order kinetics ( k 2 = 0.0289 g mg −1 min −1 , R 2 = 0.993) compared to pseudo‐first‐order ( k 1 = 0.035 min −1 , R 2 = 0.995), confirming chemisorption as the predominant mechanism. The nanocomposite demonstrated remarkable antibacterial activity against both Escherichia coli and Staphylococcus aureus , producing inhibition zones of 19 and 22 mm respectively, surpassing penicillin control against S. aureus . Recyclability studies indicated sustained performance over four consecutive cycles, maintaining 68% efficiency in the fourth cycle.