Raney copper catalysts for the water-gas shift reaction: I. Preparation, activity and stability

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

doi:10.1016/s0926-860x(97)00167-1

Cited by 41 publications

(21 citation statements)

References 28 publications

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“…Similar results are reported in the literature confirming the above reaction mechanism [5,8,[42][43][44]. WGS can be neglected under the conditions of the SR reaction [45] although copper-zinc-alumina catalysts are known to be active for low temperature WGS reaction [46,47]. The lack of CO formation was explained by the surface blocking by the strongly adsorbed methanol and methylformate [45].…”

Section: Catalytic Activitysupporting

confidence: 86%

“…OSRM takes place over copper/zinc/alumina (CZA) catalysts with high activity and selectivity to CO 2 and H 2 . Optimum feed composition was reported having oxygen to methanol and water to methanol ratios of 0.2-0.3 and 1.3-1.6, www.elsevier.com/locate/cattod Catalysis Today 120 (2007) [45][46][47][48][49][50][51][52][53] respectively [7][8][9]. The excess steam serves to reduce CO content by water-gas shift reaction:…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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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Section: Catalytic Activitysupporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Compact string reactor for autothermal hydrogen production

2007

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“…In this connection, there has been a continuing interest in catalysts, which are active in the presence of sulfur compounds [8][9][10]. Sulfided Mo-based supported systems have been designed as sulfur-resistant WGS catalysts.…”

Section: Introductionmentioning

confidence: 99%

Water–gas shift activity of K-promoted (Ni)Mo/γ-Al2O3 systems in sulfur-containing feed

Nikolova

Edreva-Kardjieva

Grozeva

2011

Reac Kinet Mech Cat

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The effect of potassium additive on the catalytic activity of nickelmolybdenum alumina-supported systems has been studied by varying the molybdenum content within 5-18 mass% MoO 3 , reaction temperature from 180 to 400 (500)°C, and steam to gas ratio of 0.3, 0.7, and 1. It has been established that potassium reduces the activity of one-component Mo-containing samples, while, independent of molybdenum loading, nickel promotes activity within the whole temperature range studied and extends the temperature range of catalytic activity by about 70°C to lower reaction temperatures. A symbatic or additive, or antibatic catalytic behavior was observed with NiMo-containing samples depending on the atomic Ni/Mo ratio and temperature range. Potassium, being a third component in tri-component KNiMo-containing samples, enhances the water-gas shift (WGS) activity depending on the atomic K/(Ni ? Mo) ratio. The activity approaches the equilibrium conversion degree in the interval of 320-500°C. A decrease in the specific surface area of calcined and tested samples relative to the bare support shows close values indicating that the overall dispersion of the species is not changed during the catalytic test. Close examination indicated that the sample containing K 2 O, NiO, and MoO 3 of 4.9, 2.5, and 12.7 mass%, respectively, was found to be the most suitable catalyst for water-gas shift reaction with sulfur containing feed since it attains equilibrium conversion even at 300°C, and at a low steam to gas ratio of 0.3 atm. This catalyst demonstrates a stable and reproducible catalytic activity as inlet gas loading is increased.

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“…Before catalytic testing, the powder samples were leached in 20 wt.% NaOH aqueous solution, similarly to the alkaline treatment of Raney catalysts [43,44]. Subsequently, the samples were kept in the alkaline solution for 2 h at ambient temperature and then kept 1 h in the boiling solution, after which they were decanted and washed with distilled water until no alkali was detected in the filtrate.…”

Section: Methodsmentioning

confidence: 99%