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O: Fachverband Oberflächenphysik

O 52: Heterogeneous Catalysis and Surface Dynamics I

O 52.3: Vortrag

Mittwoch, 29. März 2023, 11:00–11:15, TRE Phy

Transition metal carbides vs platinum as catalysts for H2 dissociation and hydrogenation of ethylene and acetylene — •Carlos Jimenez-Orozco¹, Elizabeth Florez¹, and Jose Rodriguez² — ¹Faculty of Basic Sciences, University of Medellin, Medellin, Colombia — ²Chemistry Division, Brookhaven National Laboratory, USA

Hydrogenation reactions are key in the chemical industry, many of them use the scarce Pt-group metals as catalysts, limiting their usage in the long term. Transition metal carbides (TMC) emerge as an alternative material. Among TMC, tungsten carbide (WC) stands out as the active phase or as support of metals. There is still a lack in the understanding of the WC performance, limiting their modulation and applications. Here, density functional theory was used to study the performance of WC in hydrogenation of acetylene (C2H2) and ethylene (C2H4) as probe molecules, together with the H2 dissociation capability of WC. Hence, Pt, Pt/WC (Pt monolayer) and WC were compared. Hydrogen surface coverage and atomistic thermodynamics were used to achieve more realistic models. The H2 dissociation on Pt/WC has a Pt-like behavior at high coverage. The pristine WC surface becomes as a machine for H2 dissociation in a wide rage of T and P, achieving high surface coverages. The Pt/WC has the capability to hydrogenate selectively C2H2 into C2H4, avoiding surface poisoning. The results put WC and Pt/WC under the spotlight as a promising systems alternative to Pt for hydrogenation reactions at several T and P conditions and for the selective transformation of C2H2 into C2H4.