Catalytic Application of Metal Organic Framework towards Methanol Oxidation in Direct Methanol Fuel Cell

Abstract

In this work, the catalytic activity of Cu-BTC which is also known as HKUST-1 has been measured towards Methanol oxidation reaction for Direct Methanol Fuel Cells (DMFC). The catalytic characteristics were enhanced when Graphene Oxide was added to Metal Organic Framework. CU-BTC was prepared via a facile hydrothermal method and Graphene Oxide was synthesized through Improved Hummer’s method. (1-5)wt% of GO composites with Cu-BTC were synthesized and the concentration of GO was optimized through 8wt% GO sample. As the concentration of GO was increased, catalytic testing showed superior performance due to enhanced surface area and conductivity provided by Graphene Oxide. The Cu-BTC/8wt% GO sample displayed lower catalytic activity because higher concentration of GO blocked the pores of MOF and hindered the active catalytic sites necessary for the methanol oxidation reaction to proceed. Samples were characterized through X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy. XRD showed the crystallinity of the material and reflected that the incorporation of GO did not affect the structure of the MOF. SEM revealed the morphology and symmetry of the cubic structure of the material while FTIR hinted at the functional groups that must be present and confirms the successful synthesis. Electrochemical studies were carried out through cyclic voltammetry, Electrochemical Impedance Spectroscopy and Chronoamperometry. The sample with highest concentration of GO(Cu-BTC/ 5wt% GO) displayed highest current density of 120.23mA/cm2 at a scan rate of 50mV/s, it also had the lowest charge transfer resistance(Rct) and highest capacity of 54% for retaining current over prolonged period of time as illustrated by chronoamperometry. The enhanced activity was a response of high conductive properties of GO. Keywords: Graphene Oxide, Metal Organic Frameworks, Cu-BTC, Methanol oxidation reaction, Direct methanol fuel cells, Electrocatalysis, Hydrothermal method, Improved Hummer’s method.