Development of Carbon Nanofibers/Pt Nanocomposites for Fuel Cell Application.

Abstract

Carbon nanofibers (CNFs)were prepared via the deposition of acetylene gas on bimetallic catalyst (Fe–Co) supported on kaolin in a catalytic chemical vapour reactor. Carbon nanofibers/Pt nanocomposite (Pt catalyst)was synthesized by immobilization of potassium tetrachloroplatinate (IV) (K2PtCl4) onto the carbon nanofibers (CNFs) by a wet impregnation method. The effects of mass of carbon nanofibers (CNFs) (0.25–0.30 g) and deposition time (150–180 min) on the percentage of platinum (Pt) deposited on the nanofiber were investigated. The developed CNFs/Pt was characterized using different analytical tools such as HRSEM, EDS, HRTEM, BET, TGA, XRD, XPS and cyclic voltammetry (CV). The XRD patterns revealed the crystallite size of the Pt catalyst ranged between 5.54 and 6.69 nm, and the size decreased with increasing mass of support (CNFs). The HRTEM/HRSEM analysis of the CNFs/Pt catalyst showed that the dispersion and distribution pattern and the shape of the catalyst changes as the amount of CNFs increased from 0.25 to 0.3 g. However, deposition time did not influence the crystalline nature of the catalysts. XPS analysis demonstrated the existence of different oxidation states of Pt particles on the surface of CNFs. The CV analysis revealed that CNFs/Pt catalyst supports the oxygen reduction reaction and hydrogen oxidation reaction in the fuel cell. The platinum loading of 0.002–0.004 mgpt/cm2 in the fabricated electrodes using the developed CNFs/Pt nanocomposite was compared well with other electrodes (fabricated with other support materials) such as carbon black, carbon nanotubes, aerogel and titanium.