FeOx-supported Au catalysts prepared by co-precipitation (CP) were investigated for catalytic HCHO oxidation. The applied calcination temperature was found to greatly influence both the chemical properties and microstructure of the catalysts. Characterization using XRD, H-2-TPR and XPS suggested that lower calcination temperature improves the reducibility of the catalysts, and favors the presence of surface hydroxyl groups. Consequently, an Au/FeOx catalyst calcined at 200 C afforded 100% conversion of HCHO into CO2 and H2O at room temperature and under humid air. In situ DRIFTs studies suggested that the moisture was essential for deep oxidation of the formate intermediates into CO2 and H2O, this being the rate limiting step for catalytic HCHO oxidation. (c) 2014 Elsevier B.V. All rights reserved.