Binary PtMn/C alloy catalysts with various atomic ratios (60-90 atomic% Mn) were synthesized and tested for the activity toward ethanol oxidation. The synthesized catalysts were characterized by energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). XRD studies indicate that a Pt-Mn alloy has formed in all cases. PtMn(19:81)/C and PtMn(10:90)/C exhibited the highest activity toward ethanol oxidation compared to PtMn(39:61)/C and Pt/C. XPS analysis indicates that highest activity occurs for alloys with similar surface and bulk Mn contents. (C) 2011 The Electrochemical Society. [DOI: 10.1149/2.095202jes] All rights reserved.