MoS2 nanosheets as bifunctional electrode for oxygen evolution reaction and electrochemical supercapacitor

In recent years, the demand for economic multifunctional materials for oxygen evolution reaction (OER) and supercapacitors increased tremendously. The present study focuses on the synthesis of mesoporous molybdenum disulfide nanosheets using a facile and cost-effective hydrothermal technique. The influence of acidic, alkaline, and neutral pH conditions on structural, morphological, and electrochemical properties of MoS2 has been studied in detail. The intense (0 0 2) diffraction peak evidence the growth of MoS2 along the c axis of hexagonal crystal structure. The MoS2 prepared in acidic pH condition exhibit less stacking of MoS2 layers. The pH 3 MoS2 sample possesses high specific surface area and hence affords abundant electroactive sites. The electrochemical measurements were carried out using cyclic voltammetry, galvanostatic charge-discharge, linear sweep voltammetry, and electrochemical impedance spectroscopy. The results show that the high specific capacitance of 857 F/g at 5 mV/s scan rate was achieved for the MoS2 prepared under acidic pH conditions. Further, the electrode exhibits cyclic stability of 78% even after 1000 cycles. Also, in oxygen evolution reaction, MoS2 electrocatalyst requires an overpotential of 299 mV to deliver a current of 25 mA/cm2. These results suggest that MoS2 nanosheets can serve as a potential candidate as an electrode for OER and supercapacitors.