A 49-m(2)/g TiO2 wet-imregnated with ZrO(NO3)(2), dried 6 h/105degreesC, and calcined in O-2 at 500degreesC, was treated 24 h with aq. H2PtCl6, dried and calcined 2 h/200degreesC to yield 2(or 5)%Pt/10(or 20 or 30)%ZrO2/TiO2 catalysts; 2% and 5%Pt/TiO2 were also prepared. The catalysts were reduced with H-2 in situ at 200degreesC or 500degreesC and tested, 0.26 g each, in selective reduction of 2-butenal. Conversions to 2-buten-1-ol were 70-90%, rising at 5%Pt, 20-30% ZrO2, and at a reaction temperature of 500degreesC. The 5%Pt/20(and 30)%ZrO2/TiO2 reduced at 500degreesC were most selective (about twice as much as the 2% and 5%Pt/TiO2). Temperature-programmed reductions run for 5%Pt/30%ZrO2/TiO2, TiO2, and ZrO2, suggested the ZrO2 on TiO2 to be amorphous (<3 nm) and to pass into growing crystallites at 600degreesC with ZrTiO4 formed at 700degreesC.