Preparation, characterization and activity of Au/Al2O3 catalysts modified by MgO

Series of alumina supported gold catalysts were modified by MgO. The catalysts were tested in CO oxidation using the method of temperature programmed oxidation (TPO). The introduction of MgO resulted in strong activity increase in the sub-ambient temperature region. At optimum gold and MgO content the performance of Au–MgO/Al2O3 is identical to the Au/MgO catalyst, i.e. the TPO pattern shows the characteristic U-shape behavior. This U-shape pattern is lost when the catalyst is cooled from 300 °C to sub-ambient temperature in the reaction mixture. However, re-reduction of the catalysts in hydrogen completely restores the original activity pattern. High-resolution TEM results indicate that in these catalysts Au is in the atomic closeness of magnesia.