Oxygen deficient V2O3: A stable and efficient electrocatalyst for HER and high performance EDLCs.

The demand of materials for energy conversion and storage is increasing to address the issues related to the depletion of fossil fuels. In the present study, oxygen deficient vanadium oxide (V 2 O 3) has been synthesized in an autoclave at 500 °C for 4 h. The reaction temperature, time and atmosphere affect the pure phase formation of V 2 O 3. The structural, morphological and surface characteristics of pure phase V 2 O 3 has been analysed by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS), respectively. The phase transition with respect to temperature has been confirmed by thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). The electrocatalytic hydrogen evolution reaction (HER) activity has been studied in an acidic medium. The synthesized sample shows higher cyclic stability for 1000 cyclic voltammetry (CV) cycles. It also exhibits a lower Tafel slope of 81.2 mVdec−1. The electrochemical double layer capacitance (EDLC) measurements was done via CV measurements performed at various scan rates. The observed EDLC value of synthesized sample is 242.6 μFcm−2. The study predicts potential applications of V 2 O 3 nano structures for electrochemical applications like HER and supercapacitors. • Controlled synthesis of intermediate pure V 2 O 3 nano structures. • Effect of temperature and time affect the phase transformation in an autoclave. • Efficient and stable elctrocatalyst for HER. • Oxygen deficiency in V 2 O 3 enhance the stability for capacitor applications. [ABSTRACT FROM AUTHOR]