Active sites for the selective hydrodeoxygenation of m-cresol on WOx-modified Pt

Abstract

Adsorption and reaction of m-cresol on Pt(111) and WOx-modified Pt(111) surfaces was characterized using temperature programmed desorption (TPD), high resolution electron energy loss spectroscopy (HREELS), and X-ray photoelectron spectroscopy (XPS). The results of this study show that on Pt(111) a strong interaction between the aromatic ring and the Pt surface facilitates CC bond cleavage resulting in decomposition at relatively low temperatures. In contrast, on WOx-modified Pt(111), m-cresol bonds to oxygen vacancy sites on the WOx deposits via the hydroxyl oxygen with the aromatic ring tilted away from the surface, resulting in a bonding configuration that promotes selective CO bond cleavage and limits ring hydrogenation. XPS results also show that interactions at the Pt-WOx interface help stabilize submonolayer WOx deposits in a partially reduced state, thereby maintaining a high concentration of the oxygen vacancy adsorption sites.