Preparation of Au/Y2O3 and Au/NiO catalysts by co-precipitation and their oxidation activities

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 °C. When it was calcined at 400 °C, the Y(OH)3 was transformed to yttrium oxide hydroxide (YOOH). Finally, when calcination temperature was raised to 600 °C, the YOOH was completely transformed to yttrium oxide (Y2O3). Interestingly, the gold loaded on YOOH calcined at 400 °C and gold loaded on Y2O3 calcined at 500 °C comparatively showed the highest catalytic activity for complete CO oxidation at a reaction temperature of 300 °C. The 0.12% Au/Y2O3 catalyst calcined at 500 °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 °C and 250 °C, respectively. The light-off temperatures of Au/Y2O3 and Au/NiO catalysts for methanol oxidation were 210 °C and 205 °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.