In this work, we propose a flash light-assisted facile and eco-friendly synthesis technique for Pt-based alloy nanoparticle/carbon nanotube catalysts. Pt and Pt-Ru alloy nanoparticle/multiwalled carbon nanotube (MWCNT) catalysts could be directly fabricated in a few milliseconds from MWCNTs immersed in metal precursors by flash light irradiation at room temperature and ambient conditions. The fabricated Pt-based alloy nanoparticle /MWCNT catalysts were characterized by X-ray photoelectron spectroscopy, ultraviolet-visible spectroscopy, Raman spectroscopy, and scanning electron microscopy. In order to evaluate the electro-catalytic surface area and methanol oxidation of Pt and Pt-Ru alloy catalysts, Cu-stripping voltammetry, cyclic voltammetry, linear sweep voltammetry studies and electrochemical impedance spectroscopy analysis were conducted. When compared to catalysts fabricated by a conventional chemical fabrication process, a Pt-50-Ru-50/MWCNT catalyst fabricated directly from metal precursors by flash light irradiation exhibited superior activity and stability with regard to methanol electro-oxidation. (C) 2014 The Electrochemical Society. All rights reserved.