Using Density Functional Theory (DFT), the interaction of crucial molecules involved in the selective partial oxidation of methanol to methyl formate (MF), with monometallic Au, Pd and bimetallic Au/Pd, Pd/Au core@shell catalysts is systematically investigated. The core@shell structures modeled in this study consist of Au(111), Pd(111) cores covered by monolayer of Pd, Au, respectively. Our results indicate that the adsorption strength of the molecules examined as a function of catalytic surface decreases in the order of Au/Pd(111) > Pd(111) > Au(111) > Pd/Au(111) and correlate well with the d‑band center model. The preadsorbtion of oxygen is found to have a positive impact on the selective partial oxidation reaction due to the stabilization of CH3OH and HCHO on the catalyst surface and the simultaneous intensification of MF desorption. Based on a dynamical matrix approach combined with statistical thermodynamic we propose a simple route for evaluating the Gibbs free energy of adsorption as a function of temperature. This method allows us to anticipate the relative temperature stability of molecules involved in the selective partial oxidation of methanol to MF in terms of catalytic surface.
Kamil Czelej, Karol Cwieka, Juan Carlos Colmenares and Krzysztof J. Kurzydlowski. Langmuir, 32(30) (2016) 7493 – 7502.
http://pubs.acs.org/doi/abs/10.1021/acs.langmuir.6b01906
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