Georgeite and azurite as precursors in the preparation of co-precipitated copper/zinc oxide catalysts

Pollard, A. M.; Spencer, Michael S.; Thomas, Richard; Williams, Peter A.; Holt, J.; Jennings, J. R.

doi:10.1016/0926-860x(92)80125-v

Cited by 62 publications

(37 citation statements)

References 14 publications

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“…[1] Precursor phases strongly influences the activity of the final catalyst with zincian malachite being the desired phase. [1] Its preparation by co-precipitation involves the transient formation of amorphous georgeite [2], which then transforms rapidly to crystalline malachite. The inability to synthesize stable georgeite, or even to find mineralogical examples of georgeite with high purity, has led to it being largely ignored.…”

Section: Introductionmentioning

confidence: 99%

Stable amorphous georgeite as a precursor to a high-activity catalyst

Kondrat

Smith

Wells

et al. 2016

Nature

135

105

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Section: Introductionmentioning

confidence: 99%

Stable amorphous georgeite as a precursor to a high-activity catalyst

Kondrat

Smith

Wells

et al. 2016

Nature

135

105

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“…The layers are attached together on one side by hydrogen bonding between the hydroxyl groups and oxygen from a carbonate group, while on the other side there is metal-oxygen bonding. Aurichalcite is used in industry as a catalyst precursor for hydrogenation processes and a number of studies have consequently been focussed on the study of aurichalcite [13][14][15].…”

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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“…As an intermediary phase between copper hydroxy carbonate and malachite, the presence of georgeite, which has identical composition with malachite but amorphous phase, has been suggested 10) . Also, it has been evidenced that zinc can be partially substituted of copper in georgeite to form zincian-georgeite, which transforms into malachite slowly 21) . Therefore, the precipitation of amorphous-like phase of malachite in the precursor precipitated at pH 8.8 still contains a small amount of Zn probably, and hence is through to be responsible for further interdispersion of Cu and ZnO resulting high catalytic activity.…”

Section: Preparation Of Cu/zno/al2o3 Catalyst With Superior Catalyticmentioning

confidence: 99%

“…In summary, Cu/ZnO/Al2O3 catalyst capable of methanol reforming at temperatures [20][21][22][23][24][25] lower than commercial catalysts was successfully developed. This catalyst provides enhanced energy efficiency for applications such as miniaturized reformers, which have large specific surface area.…”

Section: Preparation Of Cu/zno/al2o3 Catalyst With Superior Catalyticmentioning

confidence: 99%

Hydrogen Production by Methanol Steam Reforming Using Microreactor

Kawamura¹,

Ogura²,

Igarashi³

2013

J. Jpn. Petrol. Inst.

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A microreactor technology, in which a microchannel is used as a catalytic reaction field in order to supply hydrogen to a small polymer electrolyte fuel cell (PEFC) for portable electronic devices, was described. The reduction of heat loss in the microreactor is the primary requirement for improving system efficiency, since heat release in microreactors is higher than in conventional reactors due to the increased specific surface area. Therefore, the methanol steam reforming, operated below 300 , is an appropriate process for the hydrogen production using the microreactor. First, the high-performance Cu/ZnO/Al2O3 catalyst for methanol reforming at low temperature was developed under the optimized preparation condition. The miniaturized methanol reformer was then developed to utilize this Cu/ZnO/Al2O3 catalyst. The length of the microchannel was determined based on one-dimensional mass and heat balance analyses. The microreactor was fabricated from silicon and glass substrates using a number of microfabrication techniques. Methanol reforming using this reactor has been demonstrated to reach the levels necessary to power a 1 W-class small PEFC system. The multilayered integrating the miniature methanol reformer with a CO remover, a catalytic combustor as a heat source for methanol reforming, vaporizers, and several necessary functional elements for hydrogen production has also been successfully fabricated. Finally, the microreactor system has been demonstrated to produce hydrogen at a rate sufficient to generate electrical power of 2.5 W.

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Georgeite and azurite as precursors in the preparation of co-precipitated copper/zinc oxide catalysts

Cited by 62 publications

References 14 publications

Stable amorphous georgeite as a precursor to a high-activity catalyst

Stable amorphous georgeite as a precursor to a high-activity catalyst

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

Hydrogen Production by Methanol Steam Reforming Using Microreactor

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