New Synthetic Routes to More Active Cu/ZnO Catalysts Used for Methanol Synthesis

Kurtz, Melanie; Bauer, Natalia; Buscher, C. Thomas; Wilmer, H.; Hinrichsen, Olaf; Becker, Ralf; Rabe, Stefan; Merz, Klaus; Drieß, Matthias; Fischer, Roland A.; Mühler, Martin

doi:10.1023/b:catl.0000011085.88267.a6

Cited by 130 publications

(104 citation statements)

References 17 publications

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“…This agrees with other published results [33][34][35] reporting a linear correlation between the activity of Cu-based catalysts and the copper surface area. On the contrary, there is no clear correlation between the CO production and the surface area of ZnO carriers or copper dispersion.…”

Section: Catalytic Activity Of Cuo/zno Samples In the Conventional Resupporting

confidence: 93%

CuO/ZnO catalysts for methanol steam reforming: The role of the support polarity ratio and surface area

Mateos-Pedrero

Silva

Tanaka

et al. 2015

Applied Catalysis B: Environmental

116

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The effect of surface area and polarity ratio of ZnO support on the catalytic properties of CuO/ZnO catalyst for methanol steam reforming (MSR) are studied. The surface area of ZnO was varied changing the calcination temperature, and its polarity ratio was modified using different Zn precursors, zinc acetate and zinc nitrate. It was found that the copper dispersion and copper surface area increase with the surface area of the ZnO support, and the polarity ratio of ZnO strongly influences the reducibility of copper species. A higher polarity ratio promotes the reducibility, which is attributed to a strong interaction between copper and the more polar ZnO support. Interestingly, it was observed that the selectivity of CuO/ZnO catalysts (lower CO yield) increases with the polarity ratio of ZnO carriers. As another key result, CuO/ZnOAc375 catalyst has proven to be more selective (up to 90%) than a reference CuO/ZnO/Al2O3 sample (G66-MR, Süd Chemie).The activity of the best performing catalyst, CuO/ZnOAc-375, was assessed in a Pd-composite membrane reactor and in a conventional packed-bed reactor. A hydrogen recovery of ca. 75% and a hydrogen permeate purity of more than 90% was obtained. The Pd-based membrane reactor allowed to improve the methanol conversion, by partially suppressing the methanol steam reforming backward reaction, besides upgrading the reformate hydrogen purity for use in HT-PEMFC.2

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Section: Catalytic Activity Of Cuo/zno Samples In the Conventional Resupporting

confidence: 93%

CuO/ZnO catalysts for methanol steam reforming: The role of the support polarity ratio and surface area

Mateos-Pedrero

Silva

Tanaka

et al. 2015

Applied Catalysis B: Environmental

116

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“…However, the addition of aluminum in the precipitation process significantly changes the precursor chemistry according to the structural and electronic properties of ternary Cu/ZnO/Al 2 O 3 compared to binary Cu/ZnO catalysts. Thus, superior activities have been described for Cu/ZnO/Al 2 O 3 catalysts exhibiting a similar copper surface area like comparable Cu/ZnO catalysts [55] and [56].…”

Section: Microstructure Of Zno and Al 2 O 3 In Cu/zno/al 2 O 3 Catalystsmentioning

confidence: 90%

“…The superior activities obtained for ternary Cu/ZnO/Al 2 O 3 catalysts compared to binary Cu/ZnO catalysts with a similar copper surface area may be originating from the more complex precursor chemistry of these catalysts during the precipitation process [56]. Addition of aluminum as a third cationic component will change the electronic and structural properties of the final catalyst and may result in an enhanced activity.…”

Section: Thermal Stability Of Cu/zno/al 2 O 3 Catalystsmentioning

confidence: 99%

Microstructural characterization of Cu/ZnO/Al2O3 catalysts for methanol steam reforming—A comparative study

Kurr

Kasatkin

Girgsdies

et al. 2008

Applied Catalysis A: General

111

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Microstructural characteristics of various real Cu/ZnO/Al 2 O 3 catalysts for methanol steam reforming (MSR) were investigated by in situ X-ray diffraction (XRD), in situ X-ray absorption spectroscopy (XAS), temperature programmed reduction (TPR) and electron microscopy (TEM). Structure-activity correlations of binary Cu/ZnO model catalysts were compared to microstructural properties of the ternary catalysts obtained from in situ experiments under MSR conditions. Similar to the binary system, in addition to a high specific copper surface area the catalytic activity of Cu/ZnO/Al 2 O 3 catalysts is determined by defects in the bulk structure. The presence of lattice strain in the copper particles as the result of an advanced Cu-ZnO interface was detected only for the most active Cu/ZnO/Al 2 O 3 catalyst in this study. Complementarily, a highly defect rich nature of both Cu and ZnO has been found in the short-range order structure (XAS). Conventional TPR and TEM investigations confirm a homogeneous microstructure of Cu and ZnO particles with a narrow particle size distribution. Conversely, a heterogeneous microstructure with large copper particles and a pronounced bimodal particle size distribution was identified for the less active catalysts. Apparently, lattice strain in the copper nanoparticles is an indicator for a homogeneous microstructure of superior Cu/ZnO/Al 2 O 3 catalyst for methanol chemistry.

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“…14À17 Copper catalysts are often prepared via coprecipitation, as high loadings can be achieved in combination with high copper dispersion and good stability. 13À15, 18 Alternative methods have been explored such as chemical vapor deposition, 19,20 colloidal routes, 21 and solÀgel synthesis. 22 Preparation via pore volume impregnation is especially desirable because of its practical simplicity and small waste streams.…”

Section: ' Introductionmentioning

confidence: 99%

Copper Nitrate Redispersion To Arrive at Highly Active Silica-Supported Copper Catalysts

Munnik

Wolters

Gabrielsson³

et al. 2011

J. Phys. Chem. C

119

125

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In order to obtain copper catalysts with high dispersions at high copper loadings, the gas flow rate and gas composition was varied during calcination of silica gel impregnated with copper nitrate to a loading of 18 wt % of copper. Analysis by X-ray diffraction (XRD), N2O chemisorption, and transmission electron microscopy (TEM) showed that calcination in stagnant air resulted in very large copper crystallites and a low copper surface area (12 m2·gCu –1). A moderate flow of air was sufficient to greatly enhance the copper surface area (∼90 m2·gCu –1) based on a bimodal particle size distribution of few large crystallites and a highly dispersed phase. Changing to an N2 flow resulted in similar copper surface areas compared to samples calcined in air at the same space velocity, while calcination in a 2% NO/N2 flow resulted in a relatively narrow particle size distribution peaking around 8 nm and a slightly lower copper surface area (84 m2·gCu –1). By use of SBA-15 supported samples, in situ XRD and diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS) showed that the decomposition of copper nitrate in NO occurred via a highly dispersed copper hydroxynitrate phase, while decomposition in N2 or air occurred partly via copper nitrate anhydrate and partly via poorly dispersed copper hydroxynitrate. The high CuO dispersions after calcination in an N2 or air flow were ascribed to the redispersion of copper nitrate anhydrate by interaction with the OH groups of the silica support. By utilization of this redispersion, high copper dispersions on silica gel with concomitant high activities were obtained for the gas-phase hydrogenation of butanal.

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New Synthetic Routes to More Active Cu/ZnO Catalysts Used for Methanol Synthesis

Cited by 130 publications

References 17 publications

CuO/ZnO catalysts for methanol steam reforming: The role of the support polarity ratio and surface area

CuO/ZnO catalysts for methanol steam reforming: The role of the support polarity ratio and surface area

Microstructural characterization of Cu/ZnO/Al2O3 catalysts for methanol steam reforming—A comparative study

Copper Nitrate Redispersion To Arrive at Highly Active Silica-Supported Copper Catalysts

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