Methanol oxidation on the PtPd(111) alloy surface: A density functional theory study

Abstract

The mechanisms of methanol (CH3OH) oxidation on the PtPd(111) alloy surface were systematically investigated by using density functional theory calculations. The energies of all the involved species were analyzed. The results indicated that with the removal of H atoms from adsorbates on PtPd(111) surface, the adsorption energies of (i) CH3OH, CH2OH, CHOH, and COH increased linearly, while those of (ii) CH3OH, CH3O, CH2O, CHO, and CO exhibited odd‐even oscillation. On PtPd(111) surface, CH3OH underwent the preferred initial CH bond scission followed by successive dehydrogenation and then CHO oxidation, that is, CH3OH → CH2OH → CHOH → CHO → CHOOH → COOH → CO2. Importantly, the rate‐determining step of CH3OH oxidation was found to switch from CO → CO2 on Pt(111) to COOH → CO2 + H on PtPd(111) with a lower energy barrier of 0.96 eV. Moreover, water also decomposed into OH more easily on PtPd(111) than on Pt(111). The calculated results indicate that alloying Pt with Pd could efficiently improve its catalytic performance for CH3OH oxidation through altering the primary pathways from the CO path on pure Pt to the non‐CO path on PtPd(111).

A DFT and KMC based study on the mechanism of the water gas shift reaction on the Pd(100) surface

“…42,43 We note that the PW91 functional has been shown to be reliable for such studies. 44,45 For all the calculations an experimental lattice constant of 3.891 Å is used for bulk Pd and the ideal Pd(100) surfaces are modelled by a 3 Â 3 supercell with 4 atomic layers respectively from bulk Pd. Of the four layers we have relaxed the top two atomic-layers and fixed the bottom two layers to mimic the bulk of the system.…”

Fabrication of C@Mo Ti1−O2−δ nanocrystalline with functionalized interface as efficient and robust PtRu catalyst support for methanol electrooxidation

“…2 (a), in which two clear lattice spacings of 0.350 nm and 0.235 nm attributed to (101) and (001) of anatase TiO 2 can be identified, respectively, [51] with the grain size ranging from 8 to 13 nm. Meanwhile, the lattice spacing of 0.221 nm corresponding to the Pt (111) plane [57,58] can be detected, which indicates the successful loading of PtRu NPs on the C@MTNC-FI support. A clear tendency of PtRu NPs to deposit on the edge around the support can be observed.…”

Carbon‐Coated and Interfacial‐Functionalized Mixed‐Phase MoxTi1−xO2‐δ Nanotubes as Highly Active and Durable PtRu Catalyst Support for Methanol Electrooxidation

“…From Figure (F), 1D robust structured TNTs can be observed with a diameter of 20 to 50 nm. And Figure (A) shows the high resolution TEM (HRTEM) image of PtRu/C@IF‐MTNTs catalyst, in which lattice spacing of 0.221 nm corresponding to Pt (111) plane can be detected and the PtRu NPs tends to deposited on the edge of modified TNTs. Figure (D) suggests the core–shell nanotubes architecture and PtRu NPs are uniformly deposited on shells.…”