Raney copper catalysts for the water-gas shift reaction II. Initial catalyst optimisation

Mellor, J. R.; Coville, Neil J.; Sofianos, A.C.; Copperthwaite, Richard G.

doi:10.1016/s0926-860x(97)00168-3

Cited by 12 publications

(4 citation statements)

References 14 publications

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“…2 However, activated chemisorption is evidently not the sole factor involved in surface catalysis, as the Group 11 metals (Cu, Ag, and Au), which are very weak chemisorbers, often display marked catalytic and electrocatalytic properties. While such behavior is highlighted by recent works on supported metal electrodes, 3 copper is known to be highly active as a catalyst for both the waterÀgas shift reaction 4 and the selective oxidation of methanol to methanal; 5 it also displays unusual electrocatalytic activity for nitrate reduction to ammonia 6 in acid solution and CO 2 reduction to hydrocarbons 7 in base.…”

Section: ' Introductionmentioning

confidence: 99%

Large Amplitude Fourier Transformed AC Voltammetric Investigation of the Active State Electrochemistry of a Copper/Aqueous Base Interface and Implications for Electrocatalysis

et al. 2011

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The higher harmonic components available from large-amplitude Fourier-transformed alternating current (FT-ac) voltammetry enable the surface active state of a copper electrode in basic media to be probed in much more detail than possible with previously used dc methods. In particular, the absence of capacitance background current allows low-level Faradaic current contributions of fast electron-transfer processes to be detected; these are usually completely undetectable under conditions of dc cyclic voltammetry. Under high harmonic FT-ac voltammetric conditions, copper electrodes exhibit well-defined and reversible premonolayer oxidation responses at potentials within the double layer region in basic 1.0 M NaOH media. This process is attributed to oxidation of copper adatoms (Cu*) of low bulk metal lattice coordination numbers to surface-bonded, reactive hydrated oxide species. Of further interest is the observation that cathodic polarization in 1.0 M NaOH significantly enhances the current detected in each of the fundamental to sixth FT-ac harmonic components in the Cu*/Cu hydrous oxide electron-transfer process which enables the underlying electron transfer processes in the higher harmonics to be studied under conditions where the dc capacitance response is suppressed; the results support the incipient hydrous oxide adatom mediator (IHOAM) model of electrocatalysis. The underlying quasi-reversible interfacial Cu*/Cu hydrous oxide process present under these conditions is shown to mediate the reduction of nitrate at a copper electrode, while the mediator for the hydrazine oxidation reaction appears to involve a different mediator or active state redox couple. Use of FT-ac voltammetry offers prospects for new insights into the nature of active sites and electrocatalysis at the electrode/solution interface of Group 11 metals in aqueous media.

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Section: ' Introductionmentioning

confidence: 99%

Large Amplitude Fourier Transformed AC Voltammetric Investigation of the Active State Electrochemistry of a Copper/Aqueous Base Interface and Implications for Electrocatalysis

et al. 2011

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“…Impregnation of the Raney catalysts with chromium is known to improve the activity/selectivity of Cu-based catalyst [20][21][22]. The experimental results obtained in this study and showed in Fig.…”

Section: Influence Of Chemical Composition and Preparation Methods On mentioning

confidence: 52%

Compact string reactor for autothermal hydrogen production

2007

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This study addresses the development of a compact reactor for oxidative steam-reforming of methanol (OSRM) to produce hydrogen in autothermal mode for fuel cells. The string reactor uses catalytically active brass wires with a diameter of 500 mm placed in parallel into a tube. The micro-channels in the reactor for gases are formed between the wires presenting hydrodynamics similar to the one in multi-channel micro-reactors. Due to the high thermal conductivity of brass, the heat generated during methanol oxidation at the reactor entrance is transferred to the zone of the endothermic steam-reforming. The catalysts are prepared by Al-alloy formation on the surface of the brass wires followed by the partial leaching of Al. The catalyst presents a porous layer with the morphology of Raney metals and the chemical composition consistent with the Cu/Zn/Al-mixed oxide. The catalyst surface was additionally modified by incorporating chromium leading to Cr/Cu-spinel. This decreases the degree of the reduction of copper oxide and sintering leading to a stable catalyst. The catalyst was tested in OSRM showing high activity and selectivity to carbon dioxide and hydrogen. The string reactor presents nearly isothermal profile since the temperatures gradient within the reactor length is about 3 K. Micro-structured string reactor presents a short start-up and a fast transient behavior showing a rapid temperature change when adjusting the oxygen amount introduced into the reactor. #

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“…In the case of Cu–Al alloys, aluminum is selectively removed (2Al + 2NaOH + 6H 2 O = 2Na[Al(OH) 4 ] + 3H 2 ), whereas copper remains in the form of a nanoporous solid structure. Copper‐based Raney‐type catalysts have been successfully applied in the water–gas shift reaction or in methanol synthesis . However, the use of structured or cellular Raney‐type alloys is not very common to date.…”

Section: Introductionmentioning

confidence: 99%

“…Copperbased Raney-type catalysts have been successfully applied in the water-gas shift reaction or in methanol synthesis. [15][16][17][18] However, the use of structured or cellular Raney-type alloys is not very common to date. Only simple geometries such as diffusion-coated wire meshes or plasma spray-coated monolith structures have been achieved so far.…”

Section: Introductionmentioning

confidence: 99%

Periodic Open Cellular Raney‐Copper Catalysts Fabricated via Selective Electron Beam Melting

Wolf

et al. 2020

Adv Eng Mater

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Herein, the possibility of generating Raney‐Copper catalysts with high geometric complexity is demonstrated. For this, periodic open cellular structures (POCS) composed of a highly brittle Al–Cu alloy containing 29.4 at% copper are fabricated by selective electron beam melting (SEBM) for application in chemical reaction engineering. After selective leaching of aluminum in an NaOH solution, the POCS show a core–shell structure with a nanoporous copper surface layer and a solid core. The fabrication and dealloying processes as well as the microstructure are studied. Moreover, the SEBM‐processed Raney‐type copper catalysts show a high catalytic activity in methanol synthesis.

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Raney copper catalysts for the water-gas shift reaction II. Initial catalyst optimisation

Cited by 12 publications

References 14 publications

Large Amplitude Fourier Transformed AC Voltammetric Investigation of the Active State Electrochemistry of a Copper/Aqueous Base Interface and Implications for Electrocatalysis

Large Amplitude Fourier Transformed AC Voltammetric Investigation of the Active State Electrochemistry of a Copper/Aqueous Base Interface and Implications for Electrocatalysis

Compact string reactor for autothermal hydrogen production

Periodic Open Cellular Raney‐Copper Catalysts Fabricated via Selective Electron Beam Melting

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