PtSn/C electrocatalysts modified with Ni and Ga for the ethanol electrooxidation   

Departamento de Química, Centro de Ciências Exatas, Universidade Federal do Espírito Santo, Av. Fernando Ferrari, 514, CEP.: 29075-910, Vitória, Espírito Santo, Brazil

Adv. Mater. Lett., 2018, 9 (12), pp 895-901

DOI: 10.5185/amlett.2018.1875

Publication Date (Web): Sep 14, 2018

Copyright © IAAM-VBRI Press

E-mail: joagrothur@yahoo.com.br

Abstract

Ni and Ga elements are inexpensive compared to the Pt. Ni and NiOx have been recognized to have potential applications in ethanol electrooxidation. For these reasons and based on previous results obtained with Ga addition on Pt-based electrocatalysts we have investigated the PtSn/C electrocatalysts modified with Ni and Ga. The PtSnNiGa/C electrocatalysts were characterized in acidic medium by electrochemical techniques and by physicochemical techniques such as: X-ray diffraction; Energy dispersive X-ray spectroscopy; Transmission electron microscopy. Based on the TEM analyses, the PtSnNiGa/C electrocatalysts show average particle sizes range between 3.6 – 5.5 nm, which is consistent with XRD data. The ethanol oxidation on the PtSnNiGa/C electrocatalysts occurs at lower potentials as compared to the Pt/C. The higher current normalized by Pt mass (2.62 Ag-1Pt), lower susceptibility to poisoning anodic and charge transfer resistance (245 Ω) were obtained for the Pt₄₅Sn₂₂Ni₂₁Ga₁₂/C electrocatalyst.The current normalized by Pt mass: Pt₅₀Sn₂₆Ni₁₂Ga₁₂/C (2.8 Ag^-1Pt); Pt₄₅Sn₂₂Ni₂₁Ga₁₂/C (2.62 Ag^-1Pt); Pt₅₂Sn₂₁Ni₁₈Ga₉/C (1.63 Ag^-1Pt) and Pt₄₃Sn₂₃Ni₁₁Ga₂₂/C (1.27 Ag^-1Pt) electrocatalysts are higher compared to binary catalysts with high Pt content. The promotion effect of PtSnNiGa/C to ethanol electrooxidation can be explained by the modification structural of Pt by incorporation of Sn, Ni and/or Ga to the face-centered cubic crystalline of Pt.

Keywords

Ethanol oxidation reaction, gallium, platinum, fuel cells, quaternary electrocatalysts.