Low-temperature reduced TiO2-supported Pt and Pt-Fe catalysts are much more active and selective for the liquid phase hydrogenation of cinnamaldehyde to unsaturated cinnamyl alcohol than the corresponding carbon-supported catalysts. High-temperature reduced catalysts, where the SMSI effect should be present, are almost inactive for this reaction. There is at present no definitive explanation for this effect but an electronic metal-support interaction is most probably involved.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)