EFFECTS OF THE INTERACTION OF DISPERSED METAL PARTICLES WITH THE SUPPORT IN CATALYSTS PREPARED USING ORGANOMETALLIC COMPOUNDS

Results are reported of a systematic study of the effect of Group IVB transition metal (titanium, zirconium, hafnium) ions attached to the silica surface on the properties of dispersed palladium particles. Catalysts have been obtained from organometallic precursors. The following effects of the metal ions have been observed: (i) an increase in stability of palladium particles to sintering in hydrogen atmosphere at up to 873 K; (ii) a decrease in palladium surface coverage with chemisorbed hydrogen and carbon monoxide; (iii) an increase in TON activity and selectivity of palladium towards methanol synthesis from carbon monoxide and hydrogen; and (iv) a decrease in palladium activity in benzene hydrogenation and ethane hydrogenolysis. The data obtained have been compared with those for palladium supported on bulk TiO2 and ZrO2 and are discussed in terms of different hypotheses of the nature of a strong metal-support interaction. © 1990.