Morphology-dependent performance of MnO2 as an electrocatalyst for oxygen evolution reaction

Abstract

Manganese dioxide (MnO2) nanostructures emerged as a suitable candidate for wide range of applications due to its low toxicity, abundance and low cost. This material also possess high surface area and large number of active sites that makes it suitable for oxygen evolution reaction (OER). In the present study, effect of morphology on the OER activity of MnO2 was investigated. MnO2 of different morphology was synthesized by varying the experimental conditions. The hydrothermal and co-precipitation synthesis methods were used to prepare MnO2. For different morphologies such as hollow urchin, nanoflowers, nanorods and smooth balls of MnO2 were successfully synthesized. The presence of different phases was identified by X-ray diffraction (XRD). The morphology of the prepared samples was examined through field emission electron microscopy (FE-SEM). The prepared samples were also characterized through Raman spectroscopy and UV-visible spectroscopy. The OER activity of prepared samples was investigated through an electrochemical workstation. The best results were obtained for MnO2 nano flowers prepared using the hydrothermal method.