The objective of this work was to investigate the catalytic activity of gold catalysts supported on two metal oxides, yttrium oxide and nickel oxide, prepared by co-precipitation for CO and methanol oxidation reactions. The TGA and XRD results confirmed that yttrium hydroxide (Y(OH)3) was formed at calcination temperature below 300 degrees C. When it was calcined at 400 degrees C, the Y(OH)3 was transformed to yttrium oxide hydroxide (YOOH). Finally, when calcination temperature was raised to 600 degrees C. the YOOH was completely transformed to yttrium oxide (Y2O3). Interestingly, the gold loaded on YOOH calcined at 400 degrees C and gold loaded on Y2O3 calcined at 500 degrees C comparatively showed the highest catalytic activity for complete CO oxidation at a reaction temperature of 300 degrees C. The 0.12% Au/Y2O3 catalyst calcined at 500 degrees C was employed for both CO and methanol oxidation studies. For complete CO oxidation, the reaction temperatures of Au/Y2O3 and Au/NiO catalysts were 325 degrees C and 250 degrees C, respectively. The light-off temperatures of Au/Y2O3 and Au/NiO catalysts for methanol oxidation were 210 degrees C and 205 degrees C, respectively. Conclusively. the Au/Y2O3 clearly exhibited the same activity as that of Au/NiO for methanol oxidation while the Au/NiO gave higher activity for CO oxidation. (C) 2010 Elsevier B.V. All rights reserved.