<i>Operando</i> reaction cell for high energy surface sensitive x-ray diffraction and reflectometry

Gleißner, Robert; Beck, E.; Chung, Simon; Semione, Guilherme Dalla Lana; Mukharamova, Nastasia; Gizer, Gökhan; Pistidda, Claudio; Renner, Dru B.; Noei, Heshmat; Vonk, Vedran; Stierle, Andreas

doi:10.1063/5.0098893

Cited by 3 publications

(2 citation statements)

References 30 publications

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“…By this, key details of the complex structural interplay between basal and stepped ZnO and Cu surfaces have been revealed. In upcoming work, we strive to extend the investigations from the UHV and ambient pressure regime toward operando conditions, utilizing H 2 /CO/CO 2 gas feeds at 50 bar and 500 K. 70 ■ ASSOCIATED CONTENT * sı Supporting Information…”

Section: Acs Applied Nano Materialsmentioning

confidence: 99%

Role of Oxidation–Reduction Dynamics in the Application of Cu/ZnO-Based Catalysts

Gleißner

Chung

Semione

et al. 2023

ACS Appl. Nano Mater.

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We investigated Cu nanoparticles (NPs) on vicinal and basal ZnO supports to obtain an atomistic picture of the catalyst’s structure under in situ oxidizing and reducing conditions. The Cu/ZnO model catalysts were investigated at elevated gas pressures by high energy grazing incidence X-ray diffraction and ambient pressure X-ray photoelectron spectroscopy (AP-XPS). We find that the Cu nanoparticles are fully oxidized to Cu2O under atmospheric conditions at room temperature. As the nanoparticles swell during oxidation, they maintain their epitaxy on basal ZnO (000 ± 1) surfaces, whereas on the vicinal ZnO (101̅4) surface, the nanoparticles undergo a coherent tilt. We find that the oxidation process is fully reversible under H2 flow at 500 K, resulting in predominantly well-aligned nanoparticles on the basal surfaces, whereas the orientation of Cu NPs on vicinal ZnO was only partially restored. The analysis of the substrate crystal truncation rods evidences the stability of basal ZnO surfaces under all gas conditions. No Cu–Zn bulk alloy formation is observed. Under CO2 flow, no diffraction signal from the nanoparticles is detected, pointing to their completely disordered state. The AP-XPS results are in line with the formation of CuO. Scanning electron microscopy images show that massive mass transport has set in, leading to the formation of larger agglomerates.

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Section: Acs Applied Nano Materialsmentioning

confidence: 99%

Role of Oxidation–Reduction Dynamics in the Application of Cu/ZnO-Based Catalysts

Gleißner

Chung

Semione

et al. 2023

ACS Appl. Nano Mater.

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“…The combined use of surface science techniques at UHV and ambient pressure revealed a variety of complex structural details, which we strive to explore under operando conditions at 50 bar and beyond in future work. 70 with a depiction of respective interface models (Figure S3). Line scans over the faint features 9 and 11 of Figure 5b are shown in Figure S4 • A collection of additional figures and tables are shown in Section S4, including:…”

Section: The Cu/vzno Systemmentioning

confidence: 99%

Ambient Pressure Oxidation-Reduction Dynamics of Cu/ZnO Model Catalysts for Methanol Synthesis

Gleißner

Chung

Semione

et al. 2022

Preprint

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We investigated Cu/ZnO model catalysts for methanol synthesis to obtain an atomistic picture of activation and deactivation processes under in situ oxidizing and reducing conditions. We have investigated Cu nanoparticles with different shapes and aspect ratios grown epitaxially on basal and vicinal ZnO surfaces at elevated gas pressures by high energy grazing incidence X-ray diffraction and ambient pressure X-ray photoelectron spectroscopy (AP-XPS). We find that the Cu nanoparticles are fully oxidized to Cu2O under atmospheric conditions at room temperature. During oxidation, they maintain their epitaxy on basal ZnO (000-1) surfaces, whereas on the vicinal ZnO (10-14) surface, the nanoparticles undergo a coherent tilt. We find that the oxidation process is fully reversible under H2 flow at 500 K, resulting in predominantly well-aligned nanoparticles on the basal surfaces, whereas a random orientation is preferred for the (10-14) surface. Under CO2 flow, no diffraction signal from the nanoparticles is detected, pointing to their completely disordered state. The AP-XPS results are in line with the formation of CuO. The analysis of the substrate crystal truncation rods evidences the stability of basal ZnO surfaces under all gas conditions. No proof for Cu-Zn alloy formation is found. Scanning electron microscopy images show that massive mass transport has set in, leading to the formation of larger agglomerates, which is detrimental to the catalyst’s performance.

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In situ cell for grazing-incidence x-ray diffraction on thin films in thermal catalysis

Thum,

Arztmann,

Zizak

et al. 2024

Review of Scientific Instruments

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A cell for synchrotron-based grazing-incidence x-ray diffraction at ambient pressures and moderate temperatures in a controlled gas atmosphere is presented. The cell is suited for the in situ study of thin film samples under catalytically relevant conditions. To some extent, in addition to diffraction, the cell can be simultaneously applied for x-ray reflectometry and fluorescence studies. Different domes enclosing the sample have been studied and selected to ensure minimum contribution to the diffraction patterns. The applicability of the cell is demonstrated using synchrotron radiation by monitoring structural changes of a 3 nm Pd thin film upon interaction with gas-phase hydrogen and during acetylene semihydrogenation at 150 °C. The cell allows investigation of very thin films under catalytically relevant conditions.

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Operando reaction cell for high energy surface sensitive x-ray diffraction and reflectometry

Cited by 3 publications

References 30 publications

Role of Oxidation–Reduction Dynamics in the Application of Cu/ZnO-Based Catalysts

Role of Oxidation–Reduction Dynamics in the Application of Cu/ZnO-Based Catalysts

Ambient Pressure Oxidation-Reduction Dynamics of Cu/ZnO Model Catalysts for Methanol Synthesis

In situ cell for grazing-incidence x-ray diffraction on thin films in thermal catalysis

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