Gold nanoparticles supported on hydroxylapatite as high performance catalysts for low temperature CO oxidation

Abstract

A series of gold supported on hydroxylapatite (HAP) catalysts were prepared by deposition–precipitation with urea to study the influence of calcination atmosphere, i.e., H2, He and O2, on the performance of the catalyst in low-temperature CO oxidation. Calcination atmosphere was found to have an important influence on the catalytic activity and stability of Au/HAP. The highest initial activity was obtained for Au/HAP-He obtained by inert He-calcination, which, however, suffered the most severe deactivation with time on stream. Calcination in oxidative O2 environment resulted in the best stability and highest steady-state activity among the three catalysts. TEM results revealed that inert He-calcination can produce the smallest Au nanoparticles over the HAP support, which was suggested to be responsible for the highest initial activity of Au/HAP-He. Based on the CO2-TPD and in situ DRIFTS studies, the superior stability of Au/HAP-O2 can be attributed to a limited surface basicity in this material.