Constructing novel Ag nanoparticles anchored on MnO2 nanowires as an efficient visible light driven photocatalyst

Abstract

In this study, novel Ag@MnO₂ nanowires were constructed, using a one step hydrothermal method, which exhibited excellent efficiency towards the photodegradation of organic contaminants under visible-light driven irradiation. The resulting Ag@MnO₂ nanowires were systematically characterized using various spectroscopic and microscopic techniques. Morphological characterizations show that the Ag nanoparticles are well anchored on the surface of the MnO₂ nanowires. The N₂ adsorption/desorption studies revealed that the as prepared photocatalyst possesses mesoporosity. The optical properties and energy band gap structures were studied using UV-visible diffuse reflectance spectroscopy. The photocatalytic activity enhancement of the Ag@MnO₂ (5%) nanowires could be ascribed to the efficient separation of the photogenerated electron–hole pairs compared to other Ag@MnO₂ nanowires and pure MnO₂. The possible photocatalytic mechanism was proposed for this enhanced charge separation performance using photoluminescence spectra analysis, electrochemical impedance spectroscopy (EIS) spectra and photocurrent density. Furthermore, photocatalytic mechanism investigations demonstrate that ˙OH and O₂˙⁻ play a key role and h⁺ plays a minor role in the photocatalytic process. We believe that our findings can open a new avenue for the photocatalytic applications of Ag@MnO₂ nanowires.