Investigating the usefulness of chitosan based proton exchange membranes tailored with exfoliated molybdenum disulfide nanosheets for clean energy applications

Chitosan based proton exchange membranes (PEMs) has been synthesized by a facile solution casting strategy using two-dimensional exfoliated molybdenum disulfide (E-MoS2) nanosheets. The prepared PEMs are characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Field-emission scanning electron microscopy (FESEM) with Energy dispersive X-ray spectroscopy (EDX), water uptake, Thermogravimetric analysis (TGA), AC impedance spectroscopy and cyclic voltammetry. In comparison with pure chitosan membrane, E-MoS2 nanosheets incorporated membranes exhibit excellent water absorbing capacity, ion-exchange capacity and proton conductivity. Moreover, the changes in roughness of nanocomposite membranes is investigated by atomic force microscopy (AFM) and the results confirm that the E-MoS2 nanosheets content enhances the surface roughness as well as provide good mechanical and thermal resistivity to the chitosan/E-MoS2 membranes. Chitosan membranes with 0.75% E-MoS2 nanosheets demonstrated higher proton conductivity of 2.92 × 10-3 Scm-1 and membrane selectivity of 8.9 × 104 Scm-3 s with reduced methanol permeability of 3.28 × 10-8 cm2 s-1. Overall, results evidenced that the chitosan/E-MoS2 nanocomposite membranes will be an alternate to Nafion in direct methanol fuel cells (DMFCs).