S.P.R. Kalaikathir and S. Begila David

ABSTRACT

In the present work, carbon-supported, well-dispersed Pt100, Pt50Sn50, Pt50Co50,Pt60Sn30Co10, Pt60Sn20Co20, andPt60Sn10Co30 electrocatalysts were synthesized by Pechini method. The crystallite size, lattice parameter, composition, and particle size of metals in the electrocatalysts were determined by XRD, EDX and TEM techniques, respectively. X-ray diffraction analysis showed that catalysts have a Pt face-centred cubic (fcc) structure with crystallite size of 3–4.5 nm. The EDX results of the binary Pt–Sn/C and Pt–Co/C and the ternary Pt–Sn–Co/C catalysts were extremely close to the nominal values, indicating that the metals were loaded onto the carbon support without any obvious loss. The size of catalyst nanoparticles was observed via TEM and showed an average diameter of 3.1 nm. The electrocatalytic activities of Pt100/C, Pt50Sn50/C, Pt50Co50/C, Pt60Sn30Co10/C, Pt60Sn20Co20/C, andPt60Sn10Co30/Ccatalysts were investigated in terms of CV and CA. The electrochemical results showed that the catalytic activity in 1.0 M EtOH + 0.5 M H2SO4 solution at 0.5 V vs. Ag/AgCl exhibits the following sequence: Pt60Sn30Co10/C > Pt60Sn20Co20/C > Pt60Sn10Co30/C> Pt50Sn50/C>Pt/C > Pt50Co50/C. This clearly indicates thatthe performance of the ternary Pt60Sn30Co10/C electrocatalysts for ethanol electro-oxidation is better than that of the binary Pt50Sn50/C and Pt50Co50/C electrocatalysts due to the promoting function of Co. In addition, its CO-tolerance is better than that of the Pt50Ru50/C and Pt50Co50/C catalysts. The high activity of Pt60Ru30Co10/C electrocatalyst was also observed on membraneless ethanol fuel cell, which was consistent with the half-cell measurements. Keywords: Membraneless ethanol fuel cell, Platinum, Cobalt, Tin, and Electrocatalysts.