Electrocatalytic Application of Ni/Fe MOF for Methanol Oxidation in DMFC

Abstract

Fuel cells are the way towards green environment with its application reaching landmark where it can be employed on mass scales for consumer usage. Previously used catalyst such as Pt, Rh, Ru and Pd being expensive, faced the challenge of catalyst poisoning and slow reaction kinetics. The solution to these problems is an effective, low cost and efficient catalyst which can benefits the advantages of noble catalyst while suppressing the negatives faced by them. This thesis presents the research on novel bimetallic Ni/Fe MOF as catalyst of methanol oxidation reaction in DMFC. The catalyst was synthesized using hydrothermal process. To enhance the characteristic of catalyst, reduced graphene oxide was incorporated in catalyst with 1-5 and 8 wt%. Reduced graphene oxide (rGO) was synthesized using modified hummers method. Incorporation of rGO in Ni/Fe MOF enhanced the catalytic activity and conductivity by increasing surface area. As for the trend of 1-5 wt%, the performance of catalyst increases, however 8 wt% showed less catalytic activity due to domination of rGO on active sites of catalyst which hindered the oxidation of methanol on Ni/Fe MOF. Characterization of samples was done by SEM, XRD and FTIR. XRD described the crystallinity of catalyst and reflected that rGO has no effect on crystallinity of catalyst. SEM revealed information about morphology of catalyst and FTIR confirmed the presence of functional group in catalyst. Electrochemical studies were carried out using CV, EIS and Chronoamperometry tests. With current density of 486.14 mA/cm2, Ni/Fe MOF with 8 wt% rGO composite showed best catalytic activity at 50 mV/s scan rate. Chronoamperometry showed stability of 51% for the passage of an hour while EIS confirmed the lowest charge transfer resistance for 5 wt% rGO-Ni/Fe MOF.