B. Ohtani et al., TITANIUM(IV) OXIDE PHOTOCATALYST OF ULTRA-HIGH ACTIVITY FOR SELECTIVEN-CYCLIZATION OF AN AMINO-ACID IN AQUEOUS SUSPENSIONS, Chemical physics letters, 242(3), 1995, pp. 315-319
Titanium(IV) oxide (TiO2) powder was prepared by the high-temperature
hydrolysis of titanium(IV) tetrabutoxide in toluene as anatase crystal
lites of average diameter approximate to 15 nm. They were platinized b
y impregnation from aqueous chloroplatinic acid solution followed by h
ydrogen reduction. The catalyst was suspended in an aqueous L-lysine (
Lys) solution and photoirradiated under argon at ambient temperature t
o obtain L-pipecolinic acid (PCA). Among several platinized commercial
TiO2 powders, the present TiO2 showed the highest photocatalytic acti
vity for both Lys consumption and PCA production. This result is attri
buted to both the higher activity owing to the larger surface area wit
h lesser defects and the higher dispersion of platinum deposits acting
as an efficient reduction site for a Schiff base intermediate into PC
A.