Reaction Kinetics of Ethylene Glycol Reforming over Platinum in the Vapor versus Aqueous Phases

Kandoi, Shampa; Greeley, Jeffrey; Simonetti, Dante A.; Shabaker, John W.; Dumesic, James A.; Mavrikakis, Manos

doi:10.1021/jp104136s

Cited by 67 publications

(78 citation statements)

References 32 publications

(54 reference statements)

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“…In general, we observe that more dehydrogenated species have smaller kinetic barriers to C-O bond-breaking; this is in agreement with recent studies of C-C and C-O bond cleavage in ethylene glycol decomposition that found similar decreases in activation energy barriers for more dehydrogenated species [35,36]. However, the barrier for C-O bond breaking does not decrease monotonically with increasing dehydrogenation.…”

Section: Kinetics Of C-o Bond Breaking Eventssupporting

confidence: 92%

Dimethyl ether electro-oxidation on platinum surfaces

et al. 2016

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a b s t r a c tA first-principles density functional theory study was performed to elucidate the mechanism of dimethyl ether electro-oxidation on three low-index platinum surfaces (Pt(111), Pt(100), and Pt (211)). The goal of this study is to provide a fundamental explanation for the high activity observed experimentally on Pt (100) compared to Pt(111) and stepped surfaces. We determine that the enhanced activity of Pt(100) stems from more facile C-O bond breaking kinetics, as well as from easier removal of CO as a surface poison through activation of water. In general, the C-O bond (in CH x OCH y ) becomes easier to break as dimethyl ether is dehydrogenated to a greater extent. In contrast, dehydrogenation becomes more difficult as more hydrogen atoms are removed. We perform two analyses of probable reaction pathways, which both identify CHOC and CO as the key reaction intermediates on these Pt surfaces. We show that the reaction mechanism on each surface is dependent on the cell operating potential, as increasing the potential facilitates C-H bond scission, in turn promoting the formation of intermediates for which C-O scission is more facile. We additionally demonstrate that CO oxidation determines the high overpotential required for electro-oxidation on Pt surfaces. At practical operating potentials ( $ 0.60 V RHE ), we determine that C-O bond breaking is most likely the most difficult step on all three Pt surfaces studied.

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Section: Kinetics Of C-o Bond Breaking Eventssupporting

confidence: 92%

Dimethyl ether electro-oxidation on platinum surfaces

et al. 2016

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“…1 Hydrogen can be obtained from an aqueous solution of a (bio)carbohydrate over a Pt-based catalyst under mild conditions (ca. 200 1C, 30 bar) via aqueous phase reforming (APR): [2][3][4] C n H 2m O n + nH 2 O " nCO 2 + (m + n)H 2 (1) This route [5][6][7] gives the possibility to upgrade liquid waste streams from bio-based industries into a nearly CO-free hydrogen gas mixture with minimized energy input. 8,9 The production of hydrogen via APR is challenged by undesired side reactions like the acid catalyzed dehydration of the substrate, followed by hydrogenation over the metal surface.…”

Section: Introductionmentioning

confidence: 99%

Aqueous phase reforming in a microchannel reactor: the effect of mass transfer on hydrogen selectivity

d’Angelo

Ordomskiy

Schaaf

et al. 2013

Catal. Sci. Technol.

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Aqueous phase reforming of sorbitol was carried out in a 1.7 m long, 320 mm ID microchannel reactor with a 5 mm Pt-based washcoated catalyst layer, combined with nitrogen stripping. The performance of this microchannel reactor is correlated to the mass transfer properties, reaction kinetics, hydrogen selectivity and product distribution. Mass transfer does not affect the rate of sorbitol consumption, which is limited by the kinetics of the reforming reaction. Mass transfer significantly affects the hydrogen selectivity and the product distribution. The rapid consumption of hydrogen in side reactions at the catalyst surface is prevented by a fast mass transfer of hydrogen from the catalyst site to the gas phase in the microchannel reactor. This results in a decrease of the concentration of hydrogen at the catalyst surface, which was found to enhance the desired reforming reaction rate at the expense of the undesired hydrogen consuming reactions. Compared to a fixed bed reactor, the selectivity to hydrogen in the microchannel reactor was increased by a factor of 2. The yield of side products (mainly C3 and heavier hydrodeoxygenated species) was suppressed while the yield of hydrogen was increased from 1.4 to 4 moles per mole of sorbitol fed.

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“…The data reported in Figure 2 clearly show the huge amount of work that has been done in the investigation of the reforming of C1-C3 compounds. In particular, EG and glycerol have both been widely investigated in the literature as starting material for the production of H 2 [21,22,[24][25][26][27]. derived platform molecules.…”

Section: Aqueous Phase Reforming Of C5 and C6 Polyolsmentioning

confidence: 99%

A Short Overview on the Hydrogen Production Via Aqueous Phase Reforming (APR) of Cellulose, C6-C5 Sugars and Polyols

et al. 2019

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The use of lignocellulosic biomasses for the production of renewable hydrogen is surely among the hot-topic research tasks. In this review, we report on the recent advances in the catalytic conversion of cellulose and its derived C6-C5 sugars (glucose, fructose, and xylose) and polyols (sorbitol and xylitol) into hydrogen via aqueous phase reforming (APR) reactions. The APR processes are considered to be new sustainable catalytic routes for converting the carbohydrate fraction of biomasses into hydrogen at milder reaction conditions if compared with the traditional reforming reactions. Particular emphasis is given to the development of new and active catalysts and to the optimization of reaction conditions that aimed to maximize hydrogen production with a low concentration of CO avoiding, at the same time, the formation of alkanes.

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Reaction Kinetics of Ethylene Glycol Reforming over Platinum in the Vapor versus Aqueous Phases

Cited by 67 publications

References 32 publications

Dimethyl ether electro-oxidation on platinum surfaces

Dimethyl ether electro-oxidation on platinum surfaces

Aqueous phase reforming in a microchannel reactor: the effect of mass transfer on hydrogen selectivity

A Short Overview on the Hydrogen Production Via Aqueous Phase Reforming (APR) of Cellulose, C6-C5 Sugars and Polyols

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