Activity of calcined Ag,Cu,Au/TiO2 catalysts in the dehydrogenation/dehydration of ethanol

The catalytic activity of the anatase TiO2 and M (z+)/TiO2 with supported ions M (z+) = Ag+, Cu2+, Au3+ in vapor phase conversions of ethanol is investigated at temperatures of 100-400A degrees C. It is shown that the yields of acetaldehyde and ethylene decline for the most active catalyst Cu2+/TiO2 but increase for TiO2 and Ag/TiO2. The drop in the activation energy of the dehydrogenation reaction over calcined samples is linearly correlated with the one in the reduction potential of M (z+) to Cu+, Au+, Ag-0 and the ionic radius of M (z+) in the crystal. The energies of activation for ethylene formation change in the series TiO2 > Au3+ > Cu2+ > Ag+ and TiO2 a parts per thousand Cu2+ a parts per thousand Ag+ > Au3+ for the calcined samples. The rate of pyridine adsorption, considered as an indicator of the activity of acid sites, is a linear function of ion charge +z = 1, 2, 3, and slows by two-thirds after calcination.