Co-oxidation of CO and H-2 or oxidation of H-2 in the presence of CO was first achieved at low temperatures (0-20 degrees C) over single-component catalysts (Pd/FeOx) at a space velocity of 15.000 ml g(cat)(-1) h(-1). A systematical study of FeOx- and Al2O3-supported Pd catalysts is carried out by means of STEM, TEM, XRD, XPS, Mossbauer spectra, and time-resolved CO titration. Highly dispersed Pd nanoparticles with size 1-1.8 nm over 5.4 wt% Pd/FeOx are confirmed by HAADF-STEM and HRTEM. Time-resolved CO titration, Mossbauer spectra, and XRD and XPS results suggest FeOx support supplying active oxygen is involved in the oxidations. Particle size effect and oxygen supply from FeOx support are speculated to be the main reasons for the excellent performance of Pd/FeOx in co-oxidation of CO and H-2 or oxidation of H-2 in the presence of CO. (C) 2012 Elsevier Inc. All rights reserved.