Understanding Polyol Decomposition on Bimetallic Pt–Mo Catalysts—A DFT Study of Glycerol

Abstract

Catalytic dehydrogenation and C–C and C–O bond cleavage for glycerol decomposition on bimetallic Pt–Mo alloy model catalysts are studied using periodic density functional theory. The scaling relationship developed for monometallic systems for fast binding energy prediction has been tested and validated on both Pt-skin and Pt3Mo-skin bimetallic surfaces. Using only the binding energies of atomic C and O for corresponding alloy surfaces, this simple relationship is shown to be an extremely efficient approach to speeding up the catalytic trend analysis for bimetallic alloy catalysts. Similar to Pt(111), it is found that the Pt-skin surface also favors dehydrogenation via C–H bond cleavage and faster C–C bond cleavage over C–O bond cleavage, but the overall activity decreases compared with pure Pt. On Pt3Mo-skin surfaces, the overall reaction becomes much more exothermic, but Mo species significantly affect the selectivity by favoring the C–O bond cleavage. Thermodynamic analyses also predict that surface Mo ...