The surface chemistry of Mo(CO)(6) on Pt(1 1 0), Mo/Pt(1 1 0) and MoOx/Pt(1 1 0) surfaces was investigated by high-resolution electron energy loss spectroscopy and thermal desorption spectroscopy. The Mo/Pt(1 1 0) surface was prepared by dosing Mo(CO)(6) on Pt(1 1 0) at 700 K followed by annealing at 1000 K. The oxidation of Mo/Pt(1 1 0) surface leads to the formation of MoOx/Pt(1 1 0) surface. Mo(CO)(6) molecularly chemisorbs on the clean Pt(1 1 0) and MoOx/Pt(1 1 0) surfaces at 100 K, however, undergoes partial dissociation on the Mo/Pt(1 1 0) surface. The Mo/Pt(1 1 0) surface more strongly donates electrons to adsorbates than the Pt(1 1 0) and MoOx/Pt(1 1 0) surfaces, and thus exhibits a higher reactivity toward Mo(CO)(6). We propose that the interaction of CO ligands in Mo(CO)(6) with the metal surface determines the adsorption behavior of Mo(CO)(6). Our work enriches the surface chemistry of Mo(CO)(6), on metallic substrates. (c) 2009 Elsevier B.V. All rights reserved.