Thermochimica Acta, Vol.292, No.1-2, 169-174, 1997
TPR and TPD Investigation of Au/Alpha-Fe2O3
Temperature-programmed reduction (TPR) and temperature-programmed desorption (TPD) studies of Au/alpha-Fe2O3 and alpha-Fe2O3 samples have been carried out. It was found that the peak maximum due to the Fe2O3 --> Fe3O4 reduction of the gold-containing sample was shifted by similar to 140 K to lower temperatures in comparison with alpha-Fe2O3. A scheme of low-temperature reduction with the participation of reactive surface hydroxyl groups is proposed. By means of TPD, it was established that the hydroxyl coverage on Au/alpha-Fe2O3 was about two times higher than that on alpha-Fe2O3. A scheme is suggested which explains the continuous desorption of water to 1083 K from the surface of the gold-containing sample. The results obtained are in agreement with earlier proposed water-gas shift (WGS) reaction mechanism over Au/alpha-Fe2O3 catalysts.