Synthesis of flower-like molybdenum sulfide/graphene hybrid as an efficient oxygen reduction electrocatalyst for anion exchange membrane fuel cells

Nanostructured transition metal chalcogenides (TMCs) have significant interest towards electrochemical devices such as fuel cells, metal-ion batteries, due to their unique physical and electrochemical properties. Herein, we report a facile hydrothermal synthesis of flower-like nanostructured molybdenum sulphide and its incorporation on to graphene as a potential oxygen reduction reaction catalyst in alkaline medium. The phase purity and morphological evolution of MoS2 is systematically studied through X-ray diffraction and scanning electron microscopic techniques. The electronic states of metal and non-metallic species are deeply studied by X-ray photoelectron spectroscopy. The effect of annealing temperatures and TMC concentrations are also investigated by electrochemical techniques such as cyclic and linear sweep voltammograms. The optimised electrocatalyst (MoS2/G-500) delivers significant ORR activity with onset and half-wave potentials of 0.91 and 0.80 V (vs. RHE), respectively. Superior durability compared to state-of-art Pt/C catalyst is ascertained by repeating potential cycles for about 5000 times and also by chronoamperometric technique. Finally, the hybrid catalyst is evaluated in AEMFC as cathode catalyst which delivers peak power density of about 29 mW cm�2 under ambient temperature and pressure. The present findings emphasis that MoS2/G catalyst is promising as cost-effective and alternative to noble metal-based catalysts for fuel cell applications

Activated carbon from orange peels as supercapacitor electrode and catalyst support for oxygen reduction reaction in proton exchange membrane fuel cell

Activated carbon is synthesized using orange peel as precursor through chemical activation using H3PO4 and its ability as electrocatalyst support for ORR reaction is examined. The prepared material was subjected to various structural, compositional, morphological and electrochemical studies. For ORR activity, the platinum loaded on activated carbon (Pt/OP-AC) was investigated by cyclic voltammograms (CVs) recorded in N2 and O2 saturated 0.1 M aqueous HClO4. For supercapacitor performance, three electrode systems was tested in aqueous H2SO4 for feasibility determination and showed electrochemical double layer capacitance (EDLC) behaviour which is expected for activated carbon like materials. Electrochemical surface area (ECSA) of the activated carbon from orange peel is measured using CV. The physical properties of the prepared carbon are studied using SEM (scanning electron microscope), XRD (X-ray diffraction), Fourier transform infrared (FT-IR) spectroscopy and Raman spectroscopy. The AC derived from orange peels delivered a high specific capacitance of 275 F g �1 at 10 mV s-1 scan rate. Hence, this study suggested that orange peels may be considered not only as a potential alternative source for synthesizing carbon supported catalyst for fuel cell application but also highlight the production of low-cost carbon for further applications like supercapacitors

Activated carbon from orange peels as supercapacitor electrode and catalyst support for oxygen reduction reaction in proton exchange membrane fuel cell

Activated carbon is synthesized using orange peel as precursor through chemical activation using H3PO4 and its ability as electrocatalyst support for ORR reaction is examined. The prepared material was subjected to various structural, compositional, morphological and electrochemical studies. For ORR activity, the platinum loaded on activated carbon (Pt/OP-AC) was investigated by cyclic voltammograms (CVs) recorded in N2 and O2 saturated 0.1 M aqueous HClO4. For supercapacitor performance, three electrode systems was tested in aqueous H2SO4 for feasibility determination and showed electrochemical double layer capacitance (EDLC) behaviour which is expected for activated carbon like materials. Electrochemical surface area (ECSA) of the activated carbon from orange peel is measured using CV. The physical properties of the prepared carbon are studied using SEM (scanning electron microscope), XRD (X-ray diffraction), Fourier transform infrared (FT-IR) spectroscopy and Raman spectroscopy. The AC derived from orange peels delivered a high specific capacitance of 275 F g−1 at 10 mV s-1 scan rate. Hence, this study suggested that orange peels may be considered not only as a potential alternative source for synthesizing carbon supported catalyst for fuel cell application but also highlight the production of low-cost carbon for further applications like supercapacitors