The decomposition, dehydrogenation, self-hydrogenation, and hydrogenation of cyclohexene were used as probe reactions to determine the effects of supporting monolayer Pt on W(110) and C/W(110) surfaces. The reaction pathways were studied using temperature-programmed desorption (TPD) and high-resolution electron energy loss spectroscopy (HREELS). Oil the clean and carbon-modified W(110) surfaces, the dominant reaction pathway of cyclohexene is the complete decomposition to produce hydrogen and atomic carbon. Monolayer Pt-modification of the W(110) and C/W(110) surfaces reduces the complete decomposition and enhances the selectivity toward the dehydrogenation of cyclohexene to produce gas phase benzene. More importantly, unlike previous studies of supporting monolayer Pt on Ni and Co surfaces, neither self-hydrogenation of cyclohexene nor hydrogenation of cyclohexene with coadsorbed hydrogen is detected oil the monolayer Pt-modified W(110) and C/W(110) surfaces. The comparison is consistent with our previous density functional theory (DFT) modeling of monolayer Pt on different substrates, confirming that the chemical properties of supported Pt vary significantly on different Substrates. (c) 2005 Elsevier Inc. All rights reserved.