Hydrothermal synthesis of bifunctional Ag/MnO2 nanowires decorated with V2O5 nanorice: Photocatalytic and electrochemical impedance study for treatment of impurities present in waste water

Abstract

Organic dyes and herbicides are harmful pollutants that are being increasingly found in the water systems. To treat these waste water pollutants effectively, photocatalysis can be applied as green and eco-friendly clean up technology. In this article, a novel binary composite consisting of Ag doped MnO2 nanowires (NWs) and V2O5 nanorice (NRs) in 1:1 ratio was synthesized for photocatalytic treatment of Congo red (CR) dye and Pendimethalin (PM) herbicide. Physiochemical properties of the composite were determined by XRD, FT-IR, and SEM spectroscopy. Results revealed that the robust interfacial interactions and generation of heterojunctions among Ag/MnO2 NWs and V2O5 NRs improved the electron-hole pair separation. Due to very low aspect ratio of Ag/MnO2 NWs and V2O5 NRs in the composite, Ag/MnO2@V2O5 provided a high surface area and increased the photocatalytic performance of photocatalyst. The photocatalytic efficiency of Ag/MnO2@V2O5 for the removal of CR was 82.9% 0.0142 min−1 that was ∼2.85 and ∼4.15 times higher than Ag/MnO2 and V2O5. In addition, Ag/MnO2@V2O5 showed 50.9% degradation of PM within 120 min with rate constant value of 0.005 min−1. When applied for cyclic test, Ag/MnO2@V2O5 exhibited excellent chemical and photostability. These results proved Ag/MnO2@V2O5 as potential photocatalyst for removal of various industrial and agriculture effluents. Electrochemical impedance spectroscopic (EIS) study was also carried out using three electrode measurements. The electrochemical data obtained showed that the Ag/MnO2@V2O5 has reduced charge transfer resistance and thus electrochemical measurements confirmed the excellent performance of prepared catalyst.