Reactive MnO₂ Nanowire Template-Assisted Synthesis of Tubular Mn-Based Polypyrrole Composites for High-Performance Oxidase-like Catalysis

The development of bioinspired nanozymes with tailored activities and structural versatility remains a critical challenge in advanced enzyme-mimetic systems. Herein, we demonstrate a facile one-step hydrothermal approach for constructing one-dimensional (1D) tubular Mn-based polypyrrole (PPy) hybrid architectures using MnO2 nanowires (NWs) as dual-function templates and oxidative polymerization agents. This strategy enables precise control over compositional gradients and morphological evolution, where hydrothermal temperature emerges as a critical parameter governing the compositional and structural transformation from MnO2 NWs to MnOOH, Mn3O4, and MnCO3 nanorods embedded within conductive PPy nanotubes. Consequently, the optimized Mn3O4-based composites exhibit remarkably enhanced oxidase-mimicking activity, achieving great improvement in catalytic efficiency. Owing to this superior oxidase-like performance, a highly sensitive cysteine sensing platform was constructed. This work establishes a modular platform for designing hybrid nanozymes by integrating structural directionality (1D tubular architecture) with compositional tunability (metal oxide–polymer interfaces), offering promising opportunities in biosensing, environmental remediation, and energy-related catalytic applications.