Mechanisms of Methanol Synthesis from Carbon Dioxide and from Carbon Monoxide at Atmospheric Pressure over Cu/ZnO

Fujita, Shin‐ichiro; Usui, Masahito; Ito, Hiroto; Takezawa, Nobutsune

doi:10.1006/jcat.1995.1306

Cited by 163 publications

(129 citation statements)

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“…These transients were attributed to the spillover of reactive intermediates or hydrogen atoms from Cu to ZnO. Such spillover and a bifunctional synthesis mechanism were demonstrated by infrared spectroscopy to occur during methanol synthesis from CO 2 -containing reactants [8,38]. There is also evidence that reconstruction of Cu particles supported on ZnO [26][27][28][29] Although we detect Cu(II) in our Cu/SiO 2 catalyst, the fraction of the Cu atoms in this form does not correlate with the rate of methanol synthesis.…”

Section: Discussionmentioning

confidence: 97%

“…6 must lie in the slow accumulation of a species on the support, which participates in bifunctional methanol synthesis pathways required for CO/H 2 reactant mixtures. One possibility is that support surface hydroxyl groups are required for the formation of formate from CO/H 2 on the support, although not from CO 2 /H 2 on the Cu [11,38,39].…”

Section: Discussionmentioning

confidence: 99%

“…Other studies have shown that, on Cu/ZnO catalysts, CO 2 /H 2 mixtures produce a formate species that is an intermediate to CH 3 OH on both Cu and ZnO surfaces, but that CO/H 2 mixtures produce formate only on the ZnO support surface [8,[38][39][40][41][42][43]. SiO 2 has few hydroxyl groups, but slow methanation side reactions (Eq.…”

Section: Discussionmentioning

confidence: 99%

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New insights into methanol synthesis catalysts from X-ray absorption spectroscopy

Meitzner¹,

Iglesia

1999

Catalysis Today

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X-ray absorption spectroscopic studies from several different groups provide a consistent structural picture of methanol synthesis catalysts. Copper metal is the principal Cu species detected in all in-situ XAS studies. A small amount of Cu(II) persisted in many samples reduced below 600 K, but it appears to be catalytically irrelevant. Cu(I) was not detected in any of the in-situ XAS studies. The Zn structure did not change in response to chemical treatments in any of the ZnO-containing methanol synthesis catalysts.We conclude that the slow approach to steady-state rate of methanol synthesis from CO/H 2 mixtures cannot result from changes in the Cu metal component of Cu/SiO 2 catalysts. By eliminating this possibility, we provide indirect evidence for the proposal that initial induction periods reflect slow changes in the surface of the SiO 2 or ZnO component in the catalysts. A bifunctional mechanism involving the formation of formate from CO on support hydroxyl groups would increase methanol synthesis rates as OH groups are formed by hydrolysis of Si-O bonds using the H 2 O formed in slow methanation side reactions. The bifunctional mechanism is not required for the synthesis of methanol from CO 2 -containing mixtures, because formate can form on Cu directly from CO 2 and H 2 .

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Section: Discussionmentioning

confidence: 97%

Section: Discussionmentioning

confidence: 99%

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New insights into methanol synthesis catalysts from X-ray absorption spectroscopy

Meitzner¹,

Iglesia

1999

Catalysis Today

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“…The significance of the hydroxy carbonates precursor phases of Cu-ZnO catalysts was first highlighted by Herman et al [17] and later extended to malachite and aurichalcite [18,19]. Many have focussed on catalysts containing only copper and zinc oxide, the two components of greatest catalytic significance for hydrogenation [20][21][22] In this article, we discuss the spectral properties of synthetic aurichalcite, with variable Cu:Zn ratio, using UV-Vis and NIR spectroscopy, having in mind the thermal treatment of aurichalcite produces Cu-ZnO catalysts.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and spectroscopic characterisation of aurichalcite (Zn,Cu2+)5(CO3)2(OH)6; implications for Cu–ZnO catalyst precursors

Reddy

Frost

Locke

2007

Transition Met Chem

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The Cu-ZnO catalyst precursors with variable Cu:Zn ratio, between Zn-rich and Cu-rich compositions have been investigated by a combination of electronic and vibrational spectroscopy. Synthesized catalyst precursors exhibit two d-d transition bands of Cu 2+ ions in a distorted octahedral symmetry, at 7,600 and 12,900 cm -1 (1,315 and 775 nm). The effect of structural cation substitution (Zn 2+ and Cu 2+ ) on band shifts is observed in the spectra of the synthetic catalyst precursors. The observation of two broad features at *7,600 and 12,900 cm -1 (1,315 and 775 nm) is a strong indication for Zn 2+ substitution by Cu 2+ ions. The result of multiple bands in the symmetric stretching and bending regions confirms the reduction of symmetry from D 3h to C 2v /C s for (CO 3 ) 2-ion in aurichalcite. The synthetic aurichalcite may be used as a standard for identification of spectral properties of naturally occurring anhydrous carbonate minerals.

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“…Several studies have indicated that support composition affects the activity of Cubased catalysts for CO hydrogenation to methanol [1][2][3][4][5][6]. Zirconia has proven to be a particularly promising support for such applications, since Cu/ZrO 2 catalysts can be operated with or without the presence of CO 2 [7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Effects of cerium incorporation into zirconia on the activity of Cu/ZrO for methanol synthesis via CO hydrogenation

Pokrovski

Rhodes

Bell

2005

Journal of Catalysis

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Mechanisms of Methanol Synthesis from Carbon Dioxide and from Carbon Monoxide at Atmospheric Pressure over Cu/ZnO

Cited by 163 publications

References 0 publications

New insights into methanol synthesis catalysts from X-ray absorption spectroscopy

New insights into methanol synthesis catalysts from X-ray absorption spectroscopy

Synthesis and spectroscopic characterisation of aurichalcite (Zn,Cu2+)5(CO3)2(OH)6; implications for Cu–ZnO catalyst precursors

Effects of cerium incorporation into zirconia on the activity of Cu/ZrO for methanol synthesis via CO hydrogenation

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