Gold stabilized on various oxide supports catalyzing formaldehyde oxidation at room temperature

Abstract

Gold stabilized on reducible oxide (CeO2 and FeOx) and irreducible oxide (γ-Al2O3, SiO2, and HZSM-5) were prepared by deposition precipitation method and tested for catalytic oxidation of formaldehyde (HCHO) at room temperature under high GHSV of 600000 ml/(g·s). Au/γ-Al2O3 catalyst showed distinctive catalytic performance, presenting the highest initial HCHO conversion and stability. Correlating the reaction rate with Au particle size, there is a linear relationship, suggesting that the smaller Au particle size with higher dispersion possesses high reactivity for HCHO oxidation. All the catalysts deactivated at high GHSV (600000 ml/(g·s)), but in a quite different rate. Reducible oxide (CeO2 and FeOx) could stabilize gold through O linkage and therefore exhibits a better stability for HCHO oxidation reaction. However, the aggregation of gold particles occurred over Au/SiO2 and Au/HZSM-5 catalysts, which result in the fast deactivation. Therefore, our results suggest that the reducibility of the supports for Au catalysis has no direct influence on the activity, but affects the catalytic stability.