Dopant influence on phase and electrochemical performance of molybdenum sulfide nanostructures

Abstract

MoS2 nanostructure was successfully synthesized by employing one step solvothermal route for electrochemical water splitting applications. Generally, MoS2 nanostructures played a very important role in electrochemical energy field due to its unique physical and chemical properties [1]. In the present study, bare and Ni incorporated MoS2 nanostructures were synthesized via solvothermal route and the rhombohedral phase formation for bare and 5% Ni doped MoS2 was confirmed by X-ray diffraction (XRD) study. On further increasing the dopant concentration as 10%, the phase transformation was strongly influenced and thereby the rhombohedral phase was turned as monoclinic Mo2S3 phase and was evidenced by strong diffraction peak of plane (-101). The phase changing mechanism of Ni dopant on MoS2 nanostructures was also revealed. The luminescent nature of the synthesized nanostructures was studied by photoluminescence (PL) spectra. FTIR result clearly demonstrated the Mo-S vibration of two different phases. SEM images clearly revealed the clumsy growth of nanorods for both the phases of nanostructures. The electrochemical water splitting efficiency of different phase molybdenum sulfides have been explored by cyclic voltammetry (CV), linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS) and chronoampherometry (CA) studies. The best efficient 10% Ni doped Mo2S3 electrode governed the specific capacitance of 1207 F/g at 10 mV/s scan rate with higher current density of 193 mA/g with good conductivity. Moreover, the very good electrochemical stability was reported for the efficient electrode for 18 h with zero percent decay of its activity even after 18 h of excellent electrochemical water oxidation process. Mechanism of dopant and phase nature on electrochemical performance of the electrode was revealed. Hence, the favorable phase, dopant and morphology of molybdenum sulfide nanostructures for electrochemical water splitting applications were explored in this study.