In-situ study of reduction of copper catalysts

Vong, M. S. W.; Sermon, Paul A.; Grant, Kathryn B.

doi:10.1007/bf00764866

Cited by 20 publications

(18 citation statements)

References 28 publications

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“…The reduction process follows a sigmoidal curve of reduction rate versus reduction degree [157][158][159][160][161][162][163][164][165]. This could be explained by an induction phenomenon, by difficulties in nucleation [165,166] or by autocatalysis due to the Cu crystallites formed [167].…”

Section: Other Catalystsmentioning

confidence: 99%

“…It has been reported that reduction of CuO in a binary catalyst is retarded compared with pure CuO [62,73,157,162,164,168,169], whereas it is accelerated in ternary catalysts [169]. CO reduces CuO faster than H 2 , especially in the final stages of the reduction where it is believed that the presence of hydroxyl groups on the surface of the catalyst inhibits the reduction by H 2 [167,170].…”

Section: Other Catalystsmentioning

confidence: 99%

“…The reduction of CuO to Cu was found by some authors [164][165][166]171] to go through Cu 2 O, whereas others [162] have not identified this intermediate stage.…”

Section: Other Catalystsmentioning

confidence: 99%

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Methanol Synthesis

Hansen¹,

Nielsen²

2008

Handbook of Heterogeneous Catalysis

133

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The sections in this article are Introduction Thermodynamics Methanol Synthesis Catalysts Introduction Zn O / Cr 2 O 3 Catalyst Copper‐Based Catalysts Cu / Zn O + Element ( Al , Cr , … ) Promotion of Cu / Zn O / MOx Catalysts Cu / Zr O 2 Other Cu , Cu / Me , Cu / Me Ox Catalysts Pd ‐Based Catalysts Sulfide Catalysts Other Catalysts Activation of Cu / Zn Catalyst Activity as a Function of the Nature of Copper‐Based Catalysts Catalyst Deactivation Sintering Sulfur Poisoning Other Poisons By‐Product Formation Reaction Mechanism(s) and Active Sites Cu + in a Zn O Matrix as the Active Center The S chottky Junction Theory Partly Oxidized Copper Independent of Support as Active Sites Metallic Copper in Dynamic Interaction with the Support Cu –Zinc Surface Alloy Model Water Gas Shift Reaction Kinetics Reaction Rate Equations Diffusion Restrictions Kinetics in Slurry Phase Methanol Synthesis Methanol Synthesis Technology Synthesis Gas Preparation Natural Gas Reforming Adiabatic Pre‐Reforming Tubular, Fired Reforming Autothermal Reforming and Oxygen‐Fired Secondary Reforming Gasification of Heavy Oil, Coal or Biomass Coproduction in Ammonia Plants and Use of Off‐gases Economics of Synthesis Gas Preparation Reactor Systems and Synthesis Loop Layout Slurry Phase Reactor Types Methanol Purification Concepts Circumventing the Equilibrium Limitations Other Methanol Synthesis Routes and Technologies Methanol Synthesis by Methane Activation Conclusion

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Section: Other Catalystsmentioning

confidence: 99%

Section: Other Catalystsmentioning

confidence: 99%

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Methanol Synthesis

Hansen¹,

Nielsen²

2008

Handbook of Heterogeneous Catalysis

133

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“…The choice of CO as a probe molecule for Cu ions is implied from the existence of a characteristic carbonyl frequency shift, which depends strictly on the copper coordination environment, as well as the oxidation state [ 14 , 15 , 16 ]. In the case of Cu 2+ cations, the CO-IR analysis is insufficient, thus complementary techniques such as Electron Paramagnetic Resonance (EPR) [ 17 , 18 , 19 ], X-ray photoelectron spectroscopy (XPS) [ 20 , 21 , 22 ] and temperature-programmed reduction (TPR) [ 20 , 23 , 24 , 25 , 26 ], as well as IR studies of NO sorption, are needed to receive a detailed characterization of the oxidation state and properties of Cu in zeolites under various red-ox conditions, e.g., [ 27 , 28 , 29 ].…”

Section: Introductionmentioning

confidence: 99%

Reduction and Oxidation of Cu Species in Cu-Faujasites Studied by IR Spectroscopy

et al. 2020

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The process of reduction (by hydrogen and ethanol) and oxidation (by oxygen and NO) of Cu sites in dealuminated faujasite-type zeolites (of Si/Al = 31) was studied by infrared (IR) spectroscopy with CO (for Cu+) and NO (for Cu2+) as probe molecules. Two zeolites were studied: one of them contained mostly Cu+exch., whereas another one contained mostly Cu2+ and Cu+ox. The susceptibility of various forms of Cu for reduction were investigated. IR experiments of CO sorption evidenced that Cu+ox. was more prone for the reduction than Cu+exch. According to NO sorption studies, Cu2+exch. was reduced in the first order before Cu2+ox. Ethanol reduced mostly Cu2+ and, also, some amounts of Cu+. The treatment with oxygen caused the oxidation of Cu+ (both Cu+exch. and Cu+ox.) to Cu2+. The adsorption of NO at 190K produced Cu+(NO)2 dinitrosyls, but heating to room temperature transformed dinitrosyls to mononitrosyls and increased the Cu2+ content.

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“…The peaks at 2q ¼ 13.0 , 24.1 , 27.9 , 34.2 , 38.4 , 41.9 , 50.1 are assigned to aurichalcite phase ((Cu, Zn) 5 (CO 3 ) 2 (OH) 6 ); the peaks at 2q ¼ 18.9 , 31.7 , 32.6 , 35.4 , 42.2 , 47.6 , 58.3 , 62.8 are ascribed to malachite phase (Cu 2 CO 3 (OH) 2 ); the peaks at 2q ¼ 14.7 , 17.3 , 29.6 , 43.9 , 48.6 belong to rosasite phase ((Cu, Zn) 2 CO 3 (OH) 2 ). [22][23][24][25] From Fig. 5 we can see that the peak at 2q ¼ 13.0 is the strongest one, which can be ascribed to aurichalcite; the peaks at 2q ¼ 17.3 and 31.7 are strong peaks, which are specic to rosasite and malachite, respectively.…”

Section: Xrd Characterizationmentioning

confidence: 99%

Promoting effect of a Cu–Zn binary precursor on a ternary Cu–Zn–Al catalyst for methanol synthesis from synthesis gas

et al. 2014

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Small amounts of Cu-Zn binary precursor were introduced into traditional ternary Cu-Zn-Al catalysts to produce a series of modified ternary Cu-Zn-Al catalysts for the synthesis of methanol from synthesis gas with high CO content. 2 wt% Cu-Zn (Cu-Zn ¼ 3 : 1 atomic ratio) binary precursor was found to have the most significant improvement for the catalytic performances. Physicochemical characterization of the as-prepared catalysts by TPR, in situ XRD and in situ XAES techniques indicated that the addition of a suitable amount of binary Cu-Zn precursor partially modified the structure of the catalyst, changed the particle size of Cu, copper surface area and the ratio of Cu + /Cu 0 , and thus effectively improved the catalytic performances of the catalyst.

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In-situ study of reduction of copper catalysts

Cited by 20 publications

References 28 publications

Methanol Synthesis

Methanol Synthesis

Reduction and Oxidation of Cu Species in Cu-Faujasites Studied by IR Spectroscopy

Promoting effect of a Cu–Zn binary precursor on a ternary Cu–Zn–Al catalyst for methanol synthesis from synthesis gas

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