Pt3Ni/C and Pt3Co/C cathodes as electrocatalysts for use in oxygen sensors and proton exchange membrane fuel cells.

The composites Pt3Ni/C and Pt3Co/C are electrocatalysts for oxygen reduction reactions (ORRs). This study compares the electrocatalytic activity of these electrodes that are used to detect oxygen, and determines their suitability for use in proton exchange membrane fuel cells (PEMFCs). Chemical reduction is used to produce the Pt3Ni/C and Pt3Co/C electrocatalysts. The particle size, elemental composition and crystallinity of the intermetallic electrocatalysts are determined using transmission electron microscopy (TEM) and an energy-dispersive spectrometer (EDX). The ORR activity of the Pt3Ni/C and Pt3Co/C electrocatalysts is determined using cyclic voltammetry (CV), a polarization curve (PC) and a rotating disk electrode (RDE). The Pt3Ni/C electrode registers a greater current for the ORR as compared to the Pt3Co/C electrode. Both electrodes exhibit a linear relationship between response current and oxygen concentration in the detection range from 100 to 1000 ppm. The Pt3Ni/C electrode exhibits a significant sensitivity to oxygen up to 13.4 μA ppm−1 cm−2. A membrane electrode assembly (MEA) that is produced using Pt3Ni/C as a cathodic electrocatalyst in a single PEMFC generates a maximum power density of 1097 mW cm−2. [ABSTRACT FROM AUTHOR]