An Experimental and Kinetic Modelling Study for Methane Oxidation over Pd-based Catalyst: Inhibition by Water

Sadokhina, Nadezda; Ghasempour, Farideh; Auvray, X.; Smedler, Gudmund; Nylén, Ulf; Olofsson, Marcus; Olsson, Louise

doi:10.1007/s10562-017-2133-2

Cited by 24 publications

(23 citation statements)

References 55 publications

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“…XPS did not show any peak for elemental Pd, thereby confirming the absence of metallic palladium in the catalyst. This result is in contrast to previous research reports on the presence of metallic Pd in Pd/γ-Al2O3 catalysts [18][19][20]26]. In addition to metallic Pd and stoichiometric PdO, palladium surfaces exhibit non-stoichiometric native oxides.…”

Section: X-ray Photoelectron Spectroscopy (Xps)contrasting

confidence: 99%

“…This confirms the supposition that the γ-Al 2 O 3 support facilitated oxygen migration from the support to the stoichiometric PdO to form Pd native oxide (PdO x ). Other researchers reported the presence of Pd and/or PdO in Pd/γ-Al 2 O 3 catalysts [2,6,7,9,18,19]. Miller et al [20] and Schwartz et al [22] suggested that the support could facilitate oxygen mobility and affect composition of the surface catalytic sites at temperatures <400 • C. In order to identify the active phases in the catalytic combustion process, we did XPS of the catalyst after reaction with 2% CH4/4% O2 at 450 °C for 20 min.…”

Section: Active Phase Of the Catalyst And Proposed Mechanismmentioning

confidence: 99%

“…Deactivation by steam has been reported as a major issue with supported Pd catalysts [6,[15][16][17][18]] particularly at temperatures above 325 • C. However, Pt/Pd bimetallic catalysts were active for methane combustion in the presence of steam [6].…”

Section: Introductionmentioning

confidence: 99%

“…The nature and identity of the active phase in Pd catalysts during methane combustion is currently under dispute [2,6,7,9,[18][19][20][21]. Several researchers recognize PdO as the active phase [2,6,7,9]; some advocate for Pd [18,19], and others for the Pd to PdO ratio [20,21].…”

Section: Introductionmentioning

confidence: 99%

“…Several researchers recognize PdO as the active phase [2,6,7,9]; some advocate for Pd [18,19], and others for the Pd to PdO ratio [20,21]. Another consideration is the possibility of the support lending its constituents to the catalytic active site during the course of the reaction [20].…”

Section: Introductionmentioning

confidence: 99%

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Low-Temperature Activity and PdO-PdOx Transition in Methane Combustion by a PdO-PdOx/γ-Al2O3 Catalyst

et al. 2018

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Abstract:The search to discover a suitable catalyst for complete combustion of methane at low temperature continues to be an active area of research. We prepared a 5 wt % PdO-PdO x /γ-Al 2 O 3 catalyst by a modified Vortex-assisted Incipient Wetness Method. X-ray Photoelectron Spectroscopy showed that the original catalyst contained PdO (38%) and PdO x (62%) on the surface and indicated that PdO x originated from the interaction of PdO with the support. Scanning Transmission Electron Microscopy confirmed the catalyst had an average particle size of 10 nm and was well-dispersed in the support. The catalyst exhibited exceptional low-temperature activities with 90-94% methane conversion at 300-320 • C. The catalyst was active and stable after several catalytic runs with no signs of deactivation by steam in this narrow temperature range. However, the conversion decreased in the temperature range 325-400 • C. The surface composition changed to some extent after the reaction at 325 • C. A tentative mechanism proposes PdO x (Pd native oxide) as the active phase and migration of oxide ions from the support to PdO and then to PdO x during the catalytic oxidation. The high methane conversion at low temperature is attributed to the vortex method providing better dispersion, and to catalyst-support interaction producing the active phase of PdO x .

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Section: X-ray Photoelectron Spectroscopy (Xps)contrasting

confidence: 99%

Section: Active Phase Of the Catalyst And Proposed Mechanismmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Low-Temperature Activity and PdO-PdOx Transition in Methane Combustion by a PdO-PdOx/γ-Al2O3 Catalyst

et al. 2018

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In situ Activation of Bimetallic Pd−Pt Methane Oxidation Catalysts

et al. 2020

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This study investigates possible pathways to reduce water inhibition over Pd−Pt methane oxidation catalysts supported on alumina and a ceria‐zirconia mixed oxide under conditions typical for lean burn gas engines. Spatially resolved concentration and temperature profiles reveal that addition of hydrogen to the lean reaction mixture leads to significant heat production and an increase in methane conversion. Moreover, reductive pulses during operation are not only able to regenerate the catalyst deactivated by water by removal of OH‐groups from the catalyst surface, but even promote its activity after repeated application of pulsing for several hours. X‐ray absorption spectroscopy reveals the formation of a partially reduced PdO−Pd mixture during the pulsing, which explains the increase in activity. This state of high activity is stable for several hours under the tested lean conditions. The results presented in this study suggest an efficient in situ activation strategy to overcome water inhibition of methane total oxidation over Pd−Pt catalysts by careful process control.

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Recent Advances in Complete Methane Oxidation using Zeolite‐Supported Metal Nanoparticle Catalysts

Mortensen

Noack²,

Pedersen³

et al. 2022

ChemCatChem

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The high fuel efficiency of natural gas makes it an attractive alternative to coal and oil during the transition towards renewable energy resources. Natural gas engines are needed to ensure a stable power grid that can accommodate fluctuations in renewable energy production. Unfortunately, these engines emit as much as 3-4 % of the methane (CH 4 ) in the natural gas under learn-burn conditions. This methane slip has a high environmental cost since CH 4 is a potent greenhouse gas. Complete catalytic oxidation of CH 4 can potentially control the emission. Unfortunately, the best performing Pd/Al 2 O 3 catalysts suffer from severe deactivation under operating conditions.After decades of little progress, zeolite-supported catalysts have recently attracted increased attention. Here, we review the current status, challenges, and prospects for controlling methane emissions from large engines using zeolite-based catalysts. The determining factors for catalytic activity and stability are the zeolite topology, alumina content, counter-ion, and active metal nanoparticles incorporation. In addition, we highlight the importance of testing under realistic operation conditions. Thus, the review provides a framework for developing a catalyst technology critically needed to fulfill the Paris Climate Agreement.

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An Experimental and Kinetic Modelling Study for Methane Oxidation over Pd-based Catalyst: Inhibition by Water

Cited by 24 publications

References 55 publications

Low-Temperature Activity and PdO-PdOx Transition in Methane Combustion by a PdO-PdOx/γ-Al2O3 Catalyst

Low-Temperature Activity and PdO-PdOx Transition in Methane Combustion by a PdO-PdOx/γ-Al2O3 Catalyst

In situ Activation of Bimetallic Pd−Pt Methane Oxidation Catalysts

Recent Advances in Complete Methane Oxidation using Zeolite‐Supported Metal Nanoparticle Catalysts

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