Influence of preparation method on supported Cu–Ni alloys and their catalytic properties in high pressure CO hydrogenation

Wu, Qigang; Eriksen, Winnie L.; Duchstein, Linus Daniel Leonhard; Christensen, Jakob Munkholt; Damsgaard, Christian Danvad; Wagner, Jakob Birkedal; Temel, Burcin; Grunwaldt, Jan‐Dierk; Jensen, Anker Degn

doi:10.1039/c3cy00546a

Cited by 33 publications

(20 citation statements)

References 66 publications

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“…The XRD patterns for Ni x @Pt 100Àx samples depicted well separated peaks for Ni and Pt elements, which strongly suggest well segregated phases. 55 Another possibility is to have separated Ni and Pt nanoparticles; however, voltammetric studies show that the oxidation of Ni occurs at B0.4 V (ENH). Therefore the pure Ni core presents an oxidation peak at this potential, while only the Ni@Pt nanoparticles with the lowest amount of Pt presents a small oxidation peak indicating an incomplete Pt monolayer (ESI, † Fig.…”

Section: Resultsmentioning

confidence: 99%

Challenges of modelling real nanoparticles: Ni@Pt electrocatalysts for the oxygen reduction reaction

Ramos-Sánchez

Praserthdam

Godínez-Salomón

et al. 2015

Phys. Chem. Chem. Phys.

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Theoretical/computational methods have been extensively applied to screen possible nano-structures attempting to maximize catalytic and stability properties for applications in electrochemical devices. This work shows that the method used to model core@shell structures is of fundamental importance in order to truly represent the physicochemical changes arising from the formation of a core-shell structure. We demonstrate that using a slab approach for modelling nanoparticles the oxygen adsorption energies are qualitatively well represented. Although this is a good descriptor for the catalytic activity, huge differences are found for the calculated surface stability between the results of a nano-cluster and those of a slab approach. Moreover, for the slab method depending on the geometric properties of the core and their similarity to the elements of the core or shell, contradictory effects are obtained. In order to determine the changes occurring as the number of layers and nano particle size are increased, clusters of Ni@Pt from 13 to 260 atoms were constructed and analyzed in terms of geometric parameters, oxygen adsorption, and dissolution potential shift. It is shown that the results of modelling the Ni@Pt nanoparticles with a cluster approach are in good agreement with experimental geometrical parameters, catalytic activity, and stability of a carefully prepared series of Ni@Pt nanostructures where the shell thickness is systematically changed. The maximum catalytic activity and stability are found for a monolayer of Pt whereas adding a second and third layer the behavior is almost the same than that in pure Pt nanoparticles.

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Section: Resultsmentioning

confidence: 99%

Challenges of modelling real nanoparticles: Ni@Pt electrocatalysts for the oxygen reduction reaction

Ramos-Sánchez

Praserthdam

Godínez-Salomón

et al. 2015

Phys. Chem. Chem. Phys.

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“…Because of the multi‐tasking ability of this class of catalysts, they are used in many applications and different scientific questions are currently studied based on Cu/ZnO‐based materials. The range spans from investigations of reaction mechanisms2–4 and metal–support interaction,5–8 over catalyst stability9 to new synthesis methods10–13 and attempts to find alternatives to Cu/ZnO 14–16. Usually, the progress made in the individual studies is well documented, but—as a general problem of catalysis research—a meaningful comparison of the model catalysts or newly developed materials of different reports is often rather difficult.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Characterisation of a Highly Active Cu/ZnO:Al Catalyst

et al. 2014

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We report the application of an optimised synthesis protocol of a Cu/ZnO:Al catalyst. The different stages of synthesis are all well-characterised by using various methods with regard to the (micro-)structural, textural, solid-state kinetic, defect and surface properties. The low amount of the Al promoter (3 %) influences but does not generally change the phase evolution known for binary Cu/ZnO catalysts. Its main function seems to be the introduction of defect sites in ZnO by doping. These sites as well as the large Cu surface area are responsible for the large N₂O chemisorption capacity. Under reducing conditions, the Al promoter, just as Zn, is found enriched at the surface suggesting an active role in the strong metal–support interaction between Cu and ZnO:Al. The different stages of the synthesis are comprehensively analysed and found to be highly reproducible in the 100 g scale. The resulting catalyst is characterised by a uniform elemental distribution, small Cu particles (8 nm), a porous texture (pore size of approximately 25 nm), high specific surface area (approximately 120 m² g^-1), a high amount of defects in the Cu phase and synergetic Cu–ZnO interaction. A high and stable performance was found in methanol synthesis. We wish to establish this complex but well-studied material as a benchmark system for Cu-based catalysts

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“…The hydrogenolysis of glycerol is a structure-sensitive reaction [12,19]. The catalytic performance relies heavily on the structure of the bimetallic catalyst [12][13], which in turn is related to the catalyst preparation parameters [13][14][20][21][22][23][24]. As an example, variations in both the reduction and calcination temperatures can change the bimetallic Pt-Cu interaction and the extent of surface coverage by copper, thus affecting the catalytic performance of Pt-Cu catalysts during nitrate reduction [24].…”

Section: Introductionmentioning

confidence: 99%

Effects of pretreatment temperature on bimetallic Ir-Re catalysts for glycerol hydrogenolysis

Deng

Leng

Zhou

et al. 2015

Chinese Journal of Catalysis

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A series of bimetallic Ir-Re/KIT-6 catalysts was prepared by direct activation of impregnated samples at various reduction temperatures to study the effect of pretreatment temperature on catalyst structure and on catalytic performance for glycerol hydrogenolysis. All catalysts were characterized by N2 adsorption-desorption, transmission electron microscopy, CO chemisorption, in-situ CO adsorption diffuse reflectance infrared Fourier transform spectroscopy and temperature-programmed desorption of ammonia (NH3-TPD). The results demonstrated that those catalysts reduced at 400 to 700 °C exhibited an Ir-Re alloy structure with similar particle sizes and Ir dispersions. Furthermore, NH3-TPD results indicated that all catalysts had similar acid strengths, though acid density varied with the reduction temperature. Increasing the pretreatment temperature from 400 to 600 °C monotonically increased the acid density of the catalysts and also improved the catalytic activity for glycerol hydrogenolysis. Reducing the Ir-Re alloy catalyst at 700 °C slightly decreased the activity due to the growth of the metal particles. Moreover, a linear relationship was identified between the acid density of a catalyst and its activity, verifying the vital roles of both Re and surface acidity with regard to optimizing the performance of Ir-Re alloy catalysts.

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Influence of preparation method on supported Cu–Ni alloys and their catalytic properties in high pressure CO hydrogenation

Cited by 33 publications

References 66 publications

Challenges of modelling real nanoparticles: Ni@Pt electrocatalysts for the oxygen reduction reaction

Challenges of modelling real nanoparticles: Ni@Pt electrocatalysts for the oxygen reduction reaction

Synthesis and Characterisation of a Highly Active Cu/ZnO:Al Catalyst

Effects of pretreatment temperature on bimetallic Ir-Re catalysts for glycerol hydrogenolysis

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