Microkinetic Modeling of Ethane Total Oxidation on Pt

Abstract

Catalytic total oxidation is important in several applications. However, associated models are rather empirical. In this study, a microkinetic model is developed for ethane total oxidation, under fuel-lean conditions on a Pt catalyst using input from density functional theory and Brønsted−Evans−Polanyi linear free energy relations. Reaction orders and the apparent activation energy estimated from the model are in good agreement with experimental values. The inclusion of oxygen coverage effects on the activation of ethane changes the rate-determining step from thermal dehydrogenation to oxidative dehydrogenation of ethane. A significant portion (30%) of the reaction flux proceeds via oxygen insertion reactions to C 2 hydrocarbons (CH 2 C*).

Density-functional calculations of the conversion of methane to methanol on platinum-decorated sheets of graphene oxide

“…In this work, we used two Pt atoms loaded onto a GO sheet (C 48 O 16 ) to match the mass of composition of Pt (about 32%) within the range of experimental observation in a common Pt/GO hybrid synthesis (about 30%). 13,14 From our calculation of the density of states, we found a specific d-band structure at about +2 to +4 eV, a Pt (1) and Pt (2) are marked in Fig. 6.…”

“…Among the various tasks, it is claimed that the preparation of methanol would become an important issue in industry. [1][2][3][4][5] As methane is an abundant and readily accessible natural resource, the catalytic conversion of methane to methanol or other hydrocarbons or oxides would become a prominent issue, either experimentally or theoretically, [6][7][8][9] where the breaking of high C-H bond strength of methane is the first step to convert methane into methanol and it can be activated by catalysts (metal cluster with very high reactivity in microporous structure, or metal oxide catalysts), followed by the formation of methyl radicals to produce oxygenated products (the controlled oxidation reaction is complicated by the surroundings of the enzymatic system). According to these reports, the platinum atoms might increase the adsorption energies of hydrocarbon species, and facilitate the scission of the C-H bond.…”

“…Adsorption and reaction of CH 4 on Pt 2 /GO, Pt 2 O 2 /GO and Pt 2 O/GO sheetsTo investigate the CH 4 anchoring behavior on the Pt 2 /GO sheet, we considered several adsorption modes of CH 4 around Pt(1) and Pt (2) ; we found that the most stable structure in our calculation is IM-1 (shown in Fig.3), in which the adsorbed CH 4 is located at about Pt(2) with the calculated greatest adsorption energy, À0.53 eV, but the adsorption energies decrease to À0.11 to À0.30 eV on moving CH 4 about the Pt (1) atom that has a larger coordination number (Pt(1) already bonded to O (b) and O (c) atoms). The C-H bond of CH 4 in IM-1 became elongated to 1.16 Å (1.10 Å in a free molecule) via the activation of Pt (2) ; dehydrogenation of CH 4 required only 0.33 eV to overcome the energy barrier to form IM-2, CH 3 -Pt (2) + H-Pt (2) (slightly endothermic, 0.06 eV); the absorbed H atom on Pt (2) might subsequently transfer toward the O (c) atom to form IM-3, CH 3 -Pt (2) + HO-Pt (1) , with an energy barrier of height 0.80 eV and an exothermicity of 1.24 eV.…”

Activation Pathway of C‐H and C–C Bonds of Ethane by Pd Atom with CO2 as a Soft Oxidant

“…The noble metal (Rh, Ru, Ir, Pt and Pd) catalysts have high catalytic activity and carbon deposition resistance, and the advantages of high temperature resistance, oxidation resistance and corrosion resistance. Researchers are more concerned about Pt due to its excellent catalytic performance, but Pt is too expensive to industrial production. Pd and Pt are in the same group, have similar chemical properties, are more economical, and can be used for the activation of C−H bonds .…”

Deactivation of Pt/Al2O3 during propane oxidation at low temperatures: Kinetic regimes and platinum oxide formation

“…Due to the vast number of possible elementary reaction steps in alkane oxidation reactions, even for the simplest alkanes methane [1] and ethane [2], reaction rate equations are often simplified to include only the most kinetically-relevant step. For alkane oxidation over a typical oxidation catalyst such as platinum, several different kinetic regimes can exist in which the kinetically-relevant step and the rate equations are different in each regime.…”