Abstract: In this communication, we report a novel CoPy/C catalyst for the oxygen reduction reaction (ORR) in alkaline electrolyte using cobalt sulfate heptahydrate (CoSO₄·7H₂O) and pyridine (Py) as the Co and N precursors supported on Vulcan XC-72R, followed by heat treatment in an inert atmosphere. Electrochemical performances were evaluated using cyclic voltammograms (CVs) and rotating disk electrode (RDE) technique in terms of its ORR activity as a function of Co content in the catalyst synthesis. Results show that the presence of Co in the CoPy/C catalyst greatly affects the formation of ORR catalytic active sites and that the best performing catalyst is 10%Co%30Py/C, which was synthesized at 800°C. In 3.0 mol·L^-1 KOH, 10%Co30%Py/C (in O₂) produces an obvious ORR current with an on-set potential at 0.014 V. Compared with the 40% Py/C the on-set potential of the 10% Co30% Py/C for oxygen reduction shifted positively by 71 mV (versus RHE (reversible hydrogen electrode)) and a well-defined limiting current plateau was achieved. Therefore, a maximum current density of 1.0 mA·cm^-2 was obtained at -0.16 V with a half-wave potential of -0.07 V. Transmission electron microscopy (TEM) measurements show that the nanoparticles with a diameter of 20 nm are uniformly dispersed on Vulcan carbon (Vulcan XC-72R).

Key words: Alkaline fuel cell, CoPy/C, Heat treatment, Oxygen reduction reaction, Cyclic voltammogram, Rotating disk electrode