2H-MoS2 as an electrode material for oxygen reduction reaction and supercapacitor applications

Abstract

Molybdenum Disulfide (MoS2) is a two-dimensional material having hexagonal crystal structure, which is widely used as a catalyst in various electrochemical reactions. In the present work, 2H-MoS2 nano-structures are synthesized in the exfoliated form by a facile hydrothermal synthesis route and are studied as electrode material for electrochemical devices. Formation of 2H-MoS2 phase has been confirmed by XRD and is also supported by the presence of E12g and A1g bands in Raman spectroscopy which appears due to the formation of layered MoS2 sheets. The FESEM images show MoS2 sheets in the form of flower-like microstructures. The ORR limiting current density obtained from polarization curves is 3.51 mA/cm2 at 2400 rpm with an onset potential of 0.06 V vs RHE. The specific capacitance of 2H-MoS2 as determined from CV and GCD are 115.42 F/g (at a scan rate of 10 mV/s) and 57.69 F/g (at current density 0.5 A/g) respectively and the samples retain 71.5 % of specific capacitance after 5000 CV cycles. The sample exhibited an electrochemical double layer capacitive (EDLC) behavior with partial pseudo-capacitance. The results suggest that the MoS2-based materials are potential candidates as electrodes in the electrochemical devices.