Catalytic combustion of formaldehyde on gold/iron-oxide catalysts

A series of gold/iron-oxide catalysts for catalytic combustion of formaldehyde were prepared by co-precipitation. The catalyst containing 7.10 wt% of gold exhibited the highest catalytic activity. On this catalyst, the catalytic combustion reaction of formaldehyde proceeded at considerable rates at 20 °C and complete burn-off of formaldehyde was achieved at 80 °C. The catalysts were stable and remained active in the presence of moisture and are good substitutes for the noble metals (Pt, Pd) catalysts. The structure of catalysts, the valence state of gold and the size of gold particles were investigated by X-ray diffraction, X-ray photoelectron spectroscopy and transmission electron microscopy techniques. Gold atoms with fractional positive charge (Auδ+) were found to exist in the catalyst and play an important role in the catalytic activity. Interaction between active species and support also provided important contribution to the valence state of gold and the activity for the catalytic combustion of HCHO.