This study investigated low temperature reduction of copper oxides using modified formic acid vapor treatment with Pt catalysts in terms of reaction kinetics and mechanisms. An in situ FTIR was adopted to monitor the evolution of organic ligands and oxidized copper surface under catalyzed formic acid vapor. 350 nm-thick Cu2O can be perfectly and efficiently transformed to pure copper at 160 degrees C. Analytical results of electron paramagnetic resonance verify that HCOOH can be easily decomposed and forms hydrogen radicals through catalysis with Pt. An optimal catalytic temperature of 150 degrees C which generated the maximum amount of hydrogen radicals was suggested.