Pt-Co electrodeposited by pulse reverse current on carbon cloth (CC) and glassy carbon (GC) are studied. On both substrates, applying a higher reverse current or a longer reverse time increases the Pt content due to higher Co dissolution from Pt-Co structures, but does not affect the morphology. Despite similar morphologies and compositions deposited on CC or GC, the electrochemical behaviors of Pt-Co on both substrates are significantly different. Distinct hydrogen under-potential deposition (HUPD) adsorption/desorption peaks are not observed on CC, while well-defined peaks are established on GC. Oxygen reduction reaction (ORR) of Pt-Co on CC is significantly higher than on GC due to its highly porous structure. The ORR on GC changes with the Pt content controlled by varying the reverse pulse during electrodeposition, where Pt-Co with 58 at.% Pt or higher provides a better activity than Pt, with 77 at.% Pt having the highest ORR activity. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.