INFRARED STUDY OF SYNGAS ADSORPTION ON ZIRCONIA

The adsorption of CO, H2, and their mixtures on zirconia has been followed by FTIR technique. On samples reduced at 823 K, no hydrogen adsorbed species has been found at room temperature. Two CO species are reversibly adsorbed at room temperature giving bands at =2190 and at =2110 cm-1 assigned to CO chemisorbed on Zr4+ and Zr3+ sites, respectively. Between 423 and 673 K, the adsorption of syngas under static conditions produces formate and methoxide surface species in equilibrium. These species are intermediates in the formation of methyl alcohol and dimethyl ether produced under dynamic flow conditions on Zr02- Only the formate species remains on the surface at T > 673 K, and this species is reduced to CO by hydrogen at T = 523 K. © 1990, American Chemical Society. All rights reserved.