Well faceted palladium nanoparticies (rods, cubes, tetrahedrons, polyhedrons) supported on alumina were synthesized by a seed-mediated growth technique. The quantification of the different exposed crystallographic planes of these supported palladium nanoparticles was firstly done by TEM analysis. To get more information about the exposed crystallographic planes, the amount of defects and the accessibility of palladium sites, infrared spectroscopy measurements of an adsorbed probe molecule (CO) were also performed and enabled to improve and complete the first TEM analysis. In fact, infrared measurements allowed to evidence, and likely to quantify, the presence of crystallographic planes and defects not seen by TEM. Finally, the preferential adsorption of CTAB (cetyltrimethylammonium bromide) on low coordinative crystallographic planes was also experimentally demonstrated. (C) 2008 Elsevier B.V. All rights reserved.