Site-specific reactivity of molecules with surface defects—the case of H
 2
 dissociation on Pt

Lent, Richard van; Auras, Sabine V.; Cao, Kun; Walsh, Anton J.; Gleeson, M.A.; Juurlink, Ludo B. F.

doi:10.1126/science.aau6716

Cited by 85 publications

(75 citation statements)

References 27 publications

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“…[11] We propose here that the same interfaces can also play a pivot role to boost the catalytic deoxygenation of 3-NS. As illustrated in Figure 3 a, H 2 is readily dissociated on exposed Pt atoms into H atoms (II), [16] which can then migrate to react with the interfacial OH to produce H 2 O and Fe 2+ ions (III, Figure 3 a). In the next step, the release of H 2 O leads to the formation of a vacancy close to the five-coordinated Fe 2+ site (IV; Figure 3 a), which can capture and reduce the nitro group (V; Figure 3 a) rather than the C=C bond because of the oxophilicity of Fe 2+ .…”

Section: Angewandte Chemiementioning

confidence: 99%

Chemoselective Hydrogenation of Nitroaromatics at the Nanoscale Iron(III)–OH–Platinum Interface

et al. 2020

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Catalytic hydrogenation of nitroaromatics is an environment‐benign strategy to produce industrially important aniline intermediates. Herein, we report that Fe(OH)x deposition on Pt nanocrystals to give Fe(OH)x/Pt, enables the selective hydrogenation of nitro groups into amino groups without hydrogenating other functional groups on the aromatic ring. The unique catalytic behavior is identified to be associated with the FeIII‐OH‐Pt interfaces. While H2 activation occurs on exposed Pt atoms to ensure the high activity, the high selectivity towards the production of substituted aniline originates from the FeIII‐OH‐Pt interfaces. In situ IR, X‐ray photoelectron spectroscopy (XPS), and isotope effect studies reveal that the Fe3+/Fe2+ redox couple facilitates the hydrodeoxygenation of the ‐NO2 group during hydrogenation catalysis. Benefitting from FeIII‐OH‐Pt interfaces, the Fe(OH)x/Pt catalysts exhibit high catalytic performance towards a broad range of substituted nitroarenes.

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Section: Angewandte Chemiementioning

confidence: 99%

Chemoselective Hydrogenation of Nitroaromatics at the Nanoscale Iron(III)–OH–Platinum Interface

et al. 2020

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“…Curved surfaces of single crystals have recently been reinvented as a powerful tool to elucidate the role of specific surface sites in catalytic reactions [31][32][33]. While in the past many different types of curved surfaces have been used, in the last decade the predominantly used shapes are a small section of a cylinder and a dome [31].…”

Section: Electronic Supplementary Materialsmentioning

confidence: 99%

Chiral Surface Characterisation and Reactivity Toward H–D Exchange of a Curved Platinum Crystal

2020

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Understanding heterogeneous catalysis at the atomic level requires detailed knowledge of the reactivity of different surface sites toward specific bond breaking and bond making events. We illustrate a new method in such investigations. We use a macroscopically curved Pt single crystal containing a large variation in density of highly kinked steps of two different chiralities. Scanning tunneling microscopy maps the entire range of surface structures present on the 31° section surrounding the Pt(111) apex. Whereas most of the surface shows the expected characteristic arrays of parallel steps, hexagonally-shaped, single-atom deep pits remain after cleaning procedures near the apex. Their orientation is indicative of the different chiralities present on the two sides of the crystal’s apex. These unintended defects locally raise the surface defect concentration, but are of little consequence to subsequent reactivity measurements for $$\text {D}_2$$ D 2 dissociation and H–D exchange as probed by supersonic molecular beam techniques. We quantify absolute elementary dissociation and relative isotopic exchange rates across the surface with high spatial resolution. At low incident energies, elementary dissociation of the homonuclear isotoplogues is dominated by the kinked steps. H–D exchange kinetics depend also mostly linearly on step density. The changing ratio of D2 dissociation to H–D formation, however, suggests that anisotropic diffusion of H(D) atoms is of influence to the measured HD production rate.

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“…Many methods have been developed to study hydrogen spillover, such as scanning tunneling microscopy (STM) 9 , temperature-programmed desorption (TPD) 10 , in-situ Xray absorption spectroscopy (XAS) 11 , and low energy electron diffraction (LEED) 12 .…”

Section: Introductionmentioning

confidence: 99%

Nanometer Scale Spectroscopic Visualization of Catalytic Sites During a Hydrogenation Reaction on a Pd/Au Bimetallic Catalyst

Yin¹,

Zheng²,

Fang³

et al. 2020

Preprint

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Understanding the mechanism of catalytic hydrogenation at the local environment requires chemical and topographic information involving catalytic sites, active hydrogen species and their spatial distribution. Here, tip-enhanced Raman spectroscopy (TERS) was employed to study the catalytic hydrogenation of chloro-nitrobenzenethiol on a well-defined Pd(sub-monolayer)/Au(111) bimetallic catalyst (pH2=1.5 bar, 298 K), where the surface topography and chemical fingerprint information were simultaneously mapped with nanoscale resolution (≈10 nm). TERS imaging of the surface after catalytic hydrogenation confirms that the reaction occurs beyond the location of Pd sites. The results demonstrate that hydrogen spillover accelerates hydrogenation at the Au sites within 20 nm from the bimetallic Pd/Au boundary. Density functional theory was used to elucidate the thermodynamics of interfacial hydrogen transfer. We demonstrate that TERS as a powerful analytical tool provides a unique approach to spatially investigate the local structure-reactivity relationship in catalysis.

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Site-specific reactivity of molecules with surface defects—the case of H ₂ dissociation on Pt

Cited by 85 publications

References 27 publications

Chemoselective Hydrogenation of Nitroaromatics at the Nanoscale Iron(III)–OH–Platinum Interface

Chemoselective Hydrogenation of Nitroaromatics at the Nanoscale Iron(III)–OH–Platinum Interface

Chiral Surface Characterisation and Reactivity Toward H–D Exchange of a Curved Platinum Crystal

Nanometer Scale Spectroscopic Visualization of Catalytic Sites During a Hydrogenation Reaction on a Pd/Au Bimetallic Catalyst

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Site-specific reactivity of molecules with surface defects—the case of H 2 dissociation on Pt

Cited by 85 publications

References 27 publications

Chemoselective Hydrogenation of Nitroaromatics at the Nanoscale Iron(III)–OH–Platinum Interface

Chemoselective Hydrogenation of Nitroaromatics at the Nanoscale Iron(III)–OH–Platinum Interface

Chiral Surface Characterisation and Reactivity Toward H–D Exchange of a Curved Platinum Crystal

Nanometer Scale Spectroscopic Visualization of Catalytic Sites During a Hydrogenation Reaction on a Pd/Au Bimetallic Catalyst

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Site-specific reactivity of molecules with surface defects—the case of H ₂ dissociation on Pt