Structural Analysis of Platinum Nanoparticles on Carbon Nanotube Surface as Electrocatalyst System

Abstract

Synthesis of Pt/CNT composite by using sol gel method has been performed which the composition of CNT on the composite are vary, (x = 20, 40, 60 and 80 wt%). Performance of composite was characterized by Transmission Electron Microscope (TEM) and X-Ray Diffraction (XRD), respectively. In the refinement results of X-ray diffraction pattern, the composite consists of two phases, namely, carbon and platinum phases. Carbon phase has a structure hexagonal (P 63 m c) with lattice parameters a = b = 2.451(2) Å and c = 6.89(1) Å, α = β = 90° and γ = 120°, the unit cell volume of V = 35.8(1) A³, and the atomic density of ρ = 2.224 g.cm^-3. While platinum phase has the structure of cubic (F m -3 m) with lattice parameters a = b = c = 3.921(2) Å, α = β = γ = 90°, the unit cell volume of V = 60.3(1) A³, and the atomic density of ρ = 21.487 g.cm^-3.According to the image of TEM, the average particle size for Pt nano particle is estimated to range from 4.1-4.3 nm. While the cavity diameter average of CNT is estimated to range from 5.9-7.5 nm. Based on the calculation, the crystallite size of the Pt particle was around 4.31 nm. The optimum value of dispersed Pt into CNT occurred at 60 wt% CNT with the best composition of Pt in the unit cell of cystal structure. We concluded that this study successfully dispersed Pt nanoparticles onto CNT formed Pt/CNT composite. This was a great opportunity that the composite can be applied as electrocatalyst system on fuel cell application.