Strategies and insights towards the high performance visible light photocatalytic activity of MnO₂/PPy hybrid catalysts: challenges and perspectives

In this work, α‐MnO₂ on polypyrrole nanosheets (α‐MnO₂/PPy) were constructed via a facile hydrothermal method. The composition of MnO₂ with PPy is varied from 1, 1.5 and 2 mmol %. Tetragonal α‐MnO₂ phase with spherical particles are uniformly wrapped on the PPy nanosheets, which is determined by XRD, Raman, SEM and TEM analysis. Due to high surface area (104.52 m²/g) and porous nature (14.2 nm) of the α‐MnO₂/PPy adsorption edges were further extended with in the visible light region and simultaneous reduction of band gap energy (3.48–2.58 eV) could be observed by UV–Vis spectra. Rapid recombination process of electron–hole process was further diminished the intensity, which is analyzed through PL spectroscopy. The photocatalytic activity of the obtained catalyst was monitored using Reactive Black 31 (RB31) and 4-chlorophenol (2-CP) dyes under visible light. The outstanding degradation efficiency of 96%, high apparent constant (0.8712 min⁻¹) and desirable long term stability was observed in MnO₂/PPy composite catalyst towards RB31 dye. The improved photocatalytic mechanism has also been proposed.