Redox Properties of Cu<sub>2</sub>O(100) and (111) Surfaces

Wang, Chunlei; Tissot, Héloïse; Escudero, Carlos; Pérez-Dieste, Virgínia; Stacchiola, Darı́o; Weissenrieder, Jonas

doi:10.1021/acs.jpcc.8b08494

Cited by 38 publications

(34 citation statements)

References 61 publications

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“…High doses of hydrogen modify the surface reconstruction by interacting with several surface sites, resulting in a disordered surface (in agreement with the STM results). It has previously been reported that dissociative adsorption of O 2 on the same surface forms an O-terminated Cu 2 O(l00) surface that also modifies the surface reconstruction to give a (1 × 1) LEED pattern; however, in contrast to the H-modified surface, the (1 × 1)-O surface exhibits a high degree of surface crystallinity. , …”

Section: Resultsmentioning

confidence: 99%

Interaction of Atomic Hydrogen with the Cu₂O(100) and (111) Surfaces

et al. 2019

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Reduction of Cu2O by hydrogen is a common preparation step for heterogeneous catalysts; however, a detailed understanding of the atomic reaction pathways is still lacking. Here, we investigate the interaction of atomic hydrogen with the Cu2O(100):(3,0;1,1) and Cu2O(111):(√3 × √3)R30° surfaces using scanning tunneling microscopy (STM), low-energy electron diffraction, temperature-programmed desorption (TPD), and X-ray photoelectron spectroscopy (XPS). The experimental results are compared to density functional theory simulations. At 300 K, we identify the most favorable adsorption site on the Cu2O(100) surface: hydrogen atoms bind to an oxygen site located at the base of the atomic rows intrinsic to the (3,0;1,1) surface. The resulting hydroxyl group subsequently migrates to a nearby Cu trimer site. TPD analysis identifies H2 as the principal desorption product. These observations imply that H2 is formed through a disproportionation reaction of surface hydroxyl groups. The interaction of H with the (111) surface is more complex, including coordination to both Cu+ and OCUS sites. STM and XPS analyses reveal the formation of metallic copper clusters on the Cu2O surfaces after cycles of hydrogen exposure and annealing. The interaction of the Cu clusters with the substrate is notably different for the two surface terminations studied: after annealing, the Cu clusters coalesce on the (100) termination, and the (3,0;1,1) reconstruction is partially recovered. Clusters formed on the (111) surface are less prone to coalescence, and the (√3 × √3)R30° reconstruction was not recovered by heat treatment, indicating a weaker Cu cluster to support interaction on the (100) surface.

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Section: Resultsmentioning

confidence: 99%

Interaction of Atomic Hydrogen with the Cu₂O(100) and (111) Surfaces

et al. 2019

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“…A reducing gas mixture was selected, since the Cu 2 O(100) support is easily oxidized under high oxygen pressure. 41 The chemical state of the isolated iron motifs remains the same under reaction conditions up to 373 K. However, after increasing the temperature to 473 K, the Fe 2p signal was completely suppressed, suggesting that the ferric ions were reduced through a MvK mechanism between CO and an oxygen atom in the Fe 1 O 3 motif. This experimental result agrees with the DFT analysis that shows iron will penetrate into the Cu 2 O bulk if its coordination to oxygen is reduced from three.…”

Section: The Journal Of Physical Chemistry Lettersmentioning

confidence: 92%

“…As CO was provided in excess, this is a slightly reducing environment. A reducing gas mixture was selected, since the Cu 2 O(100) support is easily oxidized under high oxygen pressure . The chemical state of the isolated iron motifs remains the same under reaction conditions up to 373 K. However, after increasing the temperature to 473 K, the Fe 2p signal was completely suppressed, suggesting that the ferric ions were reduced through a MvK mechanism between CO and an oxygen atom in the Fe 1 O 3 motif.…”

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High-Density Isolated Fe₁O₃ Sites on a Single-Crystal Cu₂O(100) Surface

Wang

Tissot

Stenlid

et al. 2019

J. Phys. Chem. Lett.

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Inverse oxide/metal model systems are frequently used to investigate catalytic structure-function relationships at an atomic level. By means of a novel atomic layer deposition process, growth of single-site Fe 1 O x on a Pt(111) single crystal surface was achieved, as confirmed by scanning tunneling microscopy (STM). The redox properties of the catalyst were characterized by synchrotron radiation based ambient pressure X-ray photoelectron spectroscopy (AP-XPS). After calcination treatment at 373 K in 1 mbar O 2, the chemical state of the catalyst was determined as Fe 3+ . Reduction in 1 mbar H 2 at 373 K demonstrates a facile reduction to Fe 2+ and complete hydroxylation at significantly lower temperatures than what has been reported for iron oxide nanoparticles. At reaction conditions relevant for preferential oxidation of CO in H 2 (PROX), the catalyst exhibits a Fe 3+ state (ferric hydroxide) at 298 K while re-oxidation of iron oxide clusters does not occur under the same condition. CO oxidation proceeds on the single-site Fe 1 (OH) 3 through a mechanism including the loss of hydroxyl groups in the temperature range of 373 to 473 K, but no reaction is observed on iron oxide clusters. The results highlight the high flexibility of the single iron atom catalyst in switching oxidation states, not observed for iron oxide nanoparticles under similar reaction conditions, which may indicate a higher intrinsic activity of such single interfacial sites than the conventional metal-oxide interfaces. In summary, our findings of the redox properties on inverse single-site iron oxide model catalyst may provide new insights into applied Fe-Pt catalysis.

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“…Their XPS core-level spectra of Cu 2p comprise intense spin-orbit split peaks for 2p 3/2 (934.1 eV) and 2p 1/2 (954.2 eV) accompanied by satellite peaks (939-945 eV and 959-964 eV), which are typical of Cu II valency (Zatsepin et al, 1998;Momeni and Sedaghati, 2018). Besides, the remaining two main fitted peaks center at 932.4 and 952.5 eV, representing Cu 2p3/2 and Cu 2p1/2 of Cu I , respectively (Wang et al, 2018;Zhou et al, 2018). The O 1s peaks located at binding energies of 531.1 and 531.6 eV are in good agreement with the reported values of Cu 2 O and CuO, respectively (Han et al, 2018).…”

Section: Resultsmentioning

confidence: 98%

High Specific Capacity Thermal Battery Cathodes LiCu2O2 and LiCu3O3 Prepared by a Simple Solid Phase Sintering

et al. 2020

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The thermal battery has been designed to be active at high temperature to satisfy storage life and large capacity for storage and emergency power. The development of thermal battery with high specific energy requires that the cathode has high thermal stability and excellent conductivity. Here, the semiconductor material Li-Cu-O compounds LiCu 2 O 2 and LiCu 3 O 3 are synthesized by a simple solid-phase sintering technique, which is simpler than the traditional synthesis process. The thermal decomposition temperatures are 680 • C and above 900 • C, respectively. This work first applies the Li-Cu-O compounds to the thermal battery. With a cutoff voltage of 1.5 V, the specific capacities of LiCu 2 O 2 and LiCu 3 O 3 are 423 and 332 mA h g −1. Both the decomposition temperature and specific capacity are higher than in the commercial FeS 2 and CoS 2 , especially LiCu 2 O 2. This work affords an alternative of the cathode materials for high specific capacity thermal battery.

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Redox Properties of Cu₂O(100) and (111) Surfaces

Cited by 38 publications

References 61 publications

Interaction of Atomic Hydrogen with the Cu₂O(100) and (111) Surfaces

Interaction of Atomic Hydrogen with the Cu₂O(100) and (111) Surfaces

High-Density Isolated Fe₁O₃ Sites on a Single-Crystal Cu₂O(100) Surface

High Specific Capacity Thermal Battery Cathodes LiCu2O2 and LiCu3O3 Prepared by a Simple Solid Phase Sintering

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Redox Properties of Cu2O(100) and (111) Surfaces

Cited by 38 publications

References 61 publications

Interaction of Atomic Hydrogen with the Cu2O(100) and (111) Surfaces

Interaction of Atomic Hydrogen with the Cu2O(100) and (111) Surfaces

High-Density Isolated Fe1O3 Sites on a Single-Crystal Cu2O(100) Surface

High Specific Capacity Thermal Battery Cathodes LiCu2O2 and LiCu3O3 Prepared by a Simple Solid Phase Sintering

Contact Info

Product

Resources

About

Redox Properties of Cu₂O(100) and (111) Surfaces

Interaction of Atomic Hydrogen with the Cu₂O(100) and (111) Surfaces

Interaction of Atomic Hydrogen with the Cu₂O(100) and (111) Surfaces

High-Density Isolated Fe₁O₃ Sites on a Single-Crystal Cu₂O(100) Surface