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In this paper, a study on the selective hydrogenation of a,b-unsaturated aldehydes to unsaturated alco- 30a,b-unsaturated aldehydes to unsaturated alco- 30 hols (UA) by using two series of PtSn and PtFe catalysts with different metallic loadings and supported on 3131 carbon nanotubes and carbon Vulcan is reported. The catalysts were prepared by conventional impreg- 32is reported. The catalysts were prepared by conventional impreg- 32 nation using the corresponding metallic precursors, H2PtCl6, SnCl2, and FeCl3. Once reduced under hydro- 332PtCl6, SnCl2, and FeCl3. Once reduced under hydro- 33 gen flow, the supported catalysts were characterized by temperature-programmed reduction (TPR), H2 34reduction (TPR), H2 34 chemisorption, test reactions of the metallic phase, and X-ray photoelectron spectroscopy (XPS). Hydro- 35and X-ray photoelectron spectroscopy (XPS). Hydro- 35 genation results show that the addition of a second metal to Pt leads to important modification of the 3636 selectivity, although the highest selectivities to UA are reached with very different Fe or Sn loadings. 3737 The performance of the catalysts in the citral hydrogenation was related to the characteristics of the 3838 bimetallic phase. It was found that the Fe addition to Pt catalysts results in a typical behavior such as 39such as 39 for an usual ionic promoter in contact with the active metal, reaching high selectivities to UA as the Fe 4040 loading and the Fe ionic species percentage increases, while for PtSn catalysts, a high selectivity to UA 4141 was found only with a very low amount of Sn ionic species in contact with a very high percentage of 4242 Sn reduced species. The best selectivity to UA (about 98%) was found for PtSn(1wt%)/CN-P catalyst trea- 4343 ted with N2 at high temperature.2 at high temperature.