Synthesis and characterization of platinum-cobalt supported on activated carbon electrocatalyst

Abstract

Activated carbon (AC) was produced from coconut shell using phosphoric acid as an activating agent. It was characterized using X-ray diffraction (XRD), Scanning electron micrographs (SEM), Fourier transform infrared spectra (FTIR), Brunauer-Emmett-Teller (BET) and Electrical conductivity test (EC) techniques. The XRD results showed that the AC has graphitic structure while the SEM images revealed formation of pores on the AC. The FTIR spectra revealed that chemical transformation has taken place during carbonization and chemical activation, the BET results showed a specific surface area of 3927400cm²/g, pore size of 3.1nm and pore volume of 0.15cm³/g while the EC of the AC was found to be 0.025 S/cm. Pt and Pt-Co alloys with different Pt/Co ratios supported on the activated carbon were synthesized by impregnation-reduction method. The synthesized electrocatalysts were characterized by XRD, BET and EC methods. The XRD analysis confirmed the formation of Pt-Co alloy on the activated carbon and a decrease of metal particle size and lattice parameter with increase in the cobalt content. The BET results for the electrocatalysts showed the reduction in the surface area as the percentage of Pt and Co deposited on the activated carbon increased. The EC increased as the percentage of the active species deposited on the activated carbon increased. Comparative analysis of the properties of the synthesized electrocatalyst and reported electrocatalysts in the literature showed that the prepared Pt-Co/ACelectrocatalyst can be used for the methanol electro-oxidation reaction at the anode of the direct methanol fuel cell.