Comparison of Reaction Pathways of Ethylene Glycol, Acetaldehyde, and Acetic Acid on Tungsten Carbide and Ni-Modified Tungsten Carbide Surfaces

Abstract

Selectively converting biomass-derived oxygenates to H2 or syngas (H2 and CO) is critical in the utilization of biomass to replace fossil fuels. In previous studies, monolayer (ML) Ni on a Pt substrate showed enhanced conversion and selectivity for oxygenate conversion. In the current work, tungsten monocarbide (WC) is used to support monolayer Ni, with the aim of replacing ML Ni–Pt with ML Ni–WC. C2 oxygenates with different functional groups, ethylene glycol, acetaldehyde, and acetic acid, are studied on clean WC and Ni-modified WC surfaces. For each C2 oxygenate, density functional theory (DFT) calculations reveal different binding energies on WC and Ni–WC surfaces. Parallel experimental measurements using temperature programmed desorption (TPD) and high resolution electron energy loss spectroscopy (HREELS) confirm the different reaction pathways on the two types of surfaces, with the dominant decomposition pathway being C–O bond scission on clean WC and C–C bond cleavage on Ni-modified WC surfaces. Fu...