Polypyrrole‐Integrated Mg‐ZnO Nanocomposites: A Dual‐Functional Material for Photocatalytic RhB Degradation and Electrochemical Sensing

Polypyrrole (PPy) nanocomposites with variable Mg‐doped ZnO (MgZ) content (1, 3, and 6 wt%) were produced via in situ polymerization. The prepared samples have been studied using XRD, UV, SEM–EDX, IR, PL, and BET surface area analysis. XRD analysis confirmed the crystalline nature of MgZ and PPy/MgZ composites (1PMZ, 3PMZ, and 6PMZ), whereas PPy exhibited an amorphous phase. The photocatalytic activity of the produced nanocomposites was tested for the degradation of Rhodamine B (RhB) through visible light irradiation. The inclusion of PPy into MgZ successfully lowered the band gap to 2.6 eV, which increased visible light absorption. Among the prepared samples, the 3 wt% PPy/MgZ (3PMZ) nanocomposite exhibited superior photocatalytic activity, achieving 95.2% RhB degradation within 210 min. The impact of initial dye concentration, catalyst loading, and pH on the degradation efficiency was systematically estimated. Furthermore, the catalyst demonstrated excellent recyclability, retaining significant activity even after five consecutive cycles. Additionally, the electrochemical performance of 3PMZ was evaluated for dopamine (DA) detection, demonstrating its efficacy as a multifunctional material for both environmental remediation and electrochemical sensing purposes.