COMPARISON OF THE SURFACE REACTIVITY AND BULK PROPERTIES OF ZNO AND ZRO2 - SUPPORTS FOR CO HYDROGENATION CATALYSTS

ZnO and ZrO2 has been produced under basic conditions. Hydrozincite, p recipitated from a zinc acetate solution under alkaline conditions (af ter drying and calcination) transformed to ZnOy. This oxygen-deficient solid only reduced marginally in 5 kPa H-2 at a maximum rate at 770 K , as confirmed by a Zn-2p(3/2) binding energy decrease. It adsorbed CO and even more extensively CO2. This ZnOy adsorbs pyridine equally on Lewis acid sites (LAS) and Bronsted acid sites (BAS) and promotes CO h ydrogenation at 523 K to methanol to the extent of 61.9 nmol/m(2)/min. ZrO2 amorphous aerogels and crystalline xerogels adsorbed pyridine mo re in a H-bound state and promoted CO hydrogenation more to propan-2-o l at 523 K. The reasons for this surface reactivity are sought in term s of LAS-BAS concentrations and the potential of aerogel routes to ZnO are considered.