3D atom probe study of gas adsorption and reaction on alloy catalyst surfaces I: Instrumentation

Bagot, P.A.J.; Bocarmé, Thierry Visart de; Cerezo, A.; Smith, George Davey

doi:10.1016/j.susc.2006.05.026

Cited by 52 publications

(30 citation statements)

References 22 publications

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“…Further progress in these fields will require a much better understanding of how such catalysts function at the atomic level. In a previous paper [1], we introduced the catalytic atom probe (CAP), a new instrument based on the 3-dimensional atom probe (3DAP). This instrument allows atomic-scale investigation of the effects of gaseous adsorption and reaction on metal surfaces which closely approximate real catalyst particles.…”

Section: Introductionmentioning

confidence: 99%

3D atom probe study of gaseous adsorption on alloy catalyst surfaces III: Ternary alloys – NO on Pt–Rh–Ru and Pt–Rh–Ir

2008

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Section: Introductionmentioning

confidence: 99%

3D atom probe study of gaseous adsorption on alloy catalyst surfaces III: Ternary alloys – NO on Pt–Rh–Ru and Pt–Rh–Ir

2008

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“…A similar concept is the base of the 3-Dimensional Atom Probe/Atom Probe Tomography (3DAP/APT) principle [149,150]. The main idea here is not to analyse the single layer of adsorbates, but rather the distribution and the nature of atoms within the sample [151]. The system is equipped with a position sensitive detector, allowing a tomographic reconstruction of the sample, to be obtained with atomic resolution in the z-direction, together with the chemical identification of the ions.…”

Section: Field Emission Microscopy Fem/field Ion Microscopy Fimmentioning

confidence: 99%

“…The study of the adsorption of NO on Au-62 at% Pd catalysts was performed by FIM, PFDMS and CAP (Catalytic Atom Probe [151]). Even though the presence of two different metals may induce an imperfect FIM image (as compared to pure metals), it is possible to image alloys and to discern different crystallographic facets with very good accuracy, as can be seen in Figure 18a.…”

Section: Towards Denox Reactions On Au-based Catalystsmentioning

confidence: 99%

Dynamic Processes on Gold-Based Catalysts Followed by Environmental Microscopies

et al. 2017

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Abstract:Since the early discovery of the catalytic activity of gold at low temperature, there has been a growing interest in Au and Au-based catalysis for a new class of applications. The complexity of the catalysts currently used ranges from single crystal to 3D structured materials. To improve the efficiency of such catalysts, a better understanding of the catalytic process is required, from both the kinetic and material viewpoints. The understanding of such processes can be achieved using environmental imaging techniques allowing the observation of catalytic processes under reaction conditions, so as to study the systems in conditions as close as possible to industrial conditions. This review focuses on the description of catalytic processes occurring on Au-based catalysts with selected in situ imaging techniques, i.e., PEEM/LEEM, FIM/FEM and E-TEM, allowing a wide range of pressure and material complexity to be covered. These techniques, among others, are applied to unravel the presence of spatiotemporal behaviours, study mass transport and phase separation, determine activation energies of elementary steps, observe the morphological changes of supported nanoparticles, and finally correlate the surface composition with the catalytic reactivity.

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“…One particular technique of interest is ion scattering, which uses ionized gas molecules as depth sensitive probes, like low energy ion scattering [112][113][114]. When reactive gas molecules are employed as probing ion sources, like atom probe microscopy (APM), an atomically resolved layer by layer construction of catalysts can be achieved [115][116][117][118][119]. However, the destructiveness and high vacuum requirements of ion scattering and microscopy techniques are currently detrimental to their use for in situ or in operando experiments and stand as a grand challenge for their developers.…”

Section: Summary and Future Challengesmentioning

confidence: 99%

Nanocatalysis II: In Situ Surface Probes of Nano-Catalysts and Correlative Structure–Reactivity Studies

Alayoǧlu

Somorjai

2014

Catal Lett

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Model nano-catalysts with monodisperse particle sizes and architectures are essential for a fundamental understanding of surface property dynamics during catalytic reactions. Surface tools and techniques, when conducted under catalytically relevant temperature and pressure conditions, render possible measurements of dynamic surface properties such as oxidation state, composition, coordination, and bonding. Near edge X-ray absorption fine structure (NEXAFS) spectroscopy with purposely built in situ reaction cells and ambient pressure X-ray photoelectron spectroscopy (APXPS) provide (near) surface sensitive and chemical specific information on the oxidation states of metal and oxide (co-)catalysts as well as adsorbent functional elements such C, O and N under reactive gas atmospheres and even liquid environments. Likewise, sum frequency generation (SFG) vibrational spectroscopy with in situ reaction cells helps uncover the bonding geometry and configuration of the topmost surface again under conditions pertinent to catalysis. Furthermore, the local dynamics in the nanoscale and on the single particle level are revealed by environmental transmission electron microscopy (ETEM) and the spectro-microscopy techniques equipped within. A correlative approach, where an array of these in situ tools and techniques were conducted in parallel with catalytic measurements, was employed to gain molecular insight into some of the modern scientific challenges in heterogeneous catalysis.Several case examples of this correlative approach are presented here. The CO oxidation reaction over hybrid nano-catalysts of Pt nanoparticles (NPs) with various mesoporous metal oxides such as Co 3 O 4 , MnO 2 and CeO 2 was explored in relation to bifunctional catalysis and interfacial charge transfer chemistry by using in situ NEXAFS spectroscopy. Likewise, bimetallic CoPt and PtSn nanoparticle catalysts supported on silica were investigated by using a combination of in situ NEXAFS spectroscopy and APXPS. Next, CO 2 hydrogenation was carried out over bimetallic CoPt/SiO 2 and Co/TiO 2 hybrid nano-catalysts. In this case, in situ NEXAFS spectroscopy, APXPS, and ETEM indicated severe, yet reversible, surface restructuring that involved hydrogen atom spillover. Finally, *2 nm Pt NPs were investigated using in situ SFG to study hydrogenation and hydrogenative isomerization reactions. Specifically, SFG indicated that the hydrogenation of furfural and crotonaldehyde proceed by interfacial hydrogen atom spillover from TiO 2 , while the hydrogenative isomerization of methylcyclopentane (MCP) proceeds by spillover and surface diffusion of cyclohexene over mesoporous zeolites. These studies unequivocally indicated the presence of a particular reaction channel that involved one way flow of charged (i.e. electrons or protons) or neutral species (i.e. reactants) at a broadly defined interface between metals and oxides. In addition to these case studies, experimental approaches employing capillary flow micro-reactors are discussed in relation toward t...

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3D atom probe study of gas adsorption and reaction on alloy catalyst surfaces I: Instrumentation

Cited by 52 publications

References 22 publications

3D atom probe study of gaseous adsorption on alloy catalyst surfaces III: Ternary alloys – NO on Pt–Rh–Ru and Pt–Rh–Ir

3D atom probe study of gaseous adsorption on alloy catalyst surfaces III: Ternary alloys – NO on Pt–Rh–Ru and Pt–Rh–Ir

Dynamic Processes on Gold-Based Catalysts Followed by Environmental Microscopies

Nanocatalysis II: In Situ Surface Probes of Nano-Catalysts and Correlative Structure–Reactivity Studies

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