On the Real Nature of Rh Single‐Atom Catalysts Dispersed on the ZrO<sub>2</sub> Surface

Thang, Ho Viet; Pacchioni, Gianfranco

doi:10.1002/cctc.201901878

Cited by 25 publications

(27 citation statements)

References 64 publications

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“…We used spin-polarized DFT as implemented in the Vienna Ab initio Package. The self-interaction problem inherent with this functional has been partly removed by applying the DFT + U approach, where the Hubbard’s U parameter for the 4d orbitals of the Zr ions was set to 4 eV ( 49 ). Core-valence and electron-electron interactions were treated by the projector augmented wave method ( 50 ) and the Perdew-Burke-Ernzerhof generalized gradient approximation ( 51 , 52 ).…”

Section: Methodsmentioning

confidence: 99%

Oxygen-deficient metal oxides supported nano-intermetallic InNi ₃ C _0.5 toward efficient CO ₂ hydrogenation to methanol

et al. 2021

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Direct CO2 hydrogenation to methanol using renewable energy–generated hydrogen is attracting intensive attention, but qualifying catalysts represents a grand challenge. Pure-/multi-metallic systems used for this task usually have low catalytic activity. Here, we tailored a highly active and selective InNi3C0.5/ZrO2 catalyst by tuning the performance-relevant electronic metal-support interaction (EMSI), which is tightly linked with the ZrO2 type–dependent oxygen deficiency. Highly oxygen-deficient monoclinic-ZrO2 support imparts high electron density to InNi3C0.5 because of the considerably enhanced EMSI, thereby enabling InNi3C0.5/monoclinic-ZrO2 with an intrinsic activity three or two times as high as that of InNi3C0.5/amorphous-ZrO2 or InNi3C0.5/tetragonal-ZrO2. The EMSI-governed catalysis observed in the InNi3C0.5/ZrO2 system is extendable to other oxygen-deficient metal oxides, in particular InNi3C0.5/Fe3O4, achieving 25.7% CO2 conversion with 90.2% methanol selectivity at 325°C, 6.0 MPa, 36,000 ml gcat−1 hour−1, and H2/CO2 = 10:1. This affordable catalyst is stable for at least 500 hours and is also highly resistant to sulfur poisoning.

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Section: Methodsmentioning

confidence: 99%

Oxygen-deficient metal oxides supported nano-intermetallic InNi ₃ C _0.5 toward efficient CO ₂ hydrogenation to methanol

et al. 2021

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“…Here for example, Thang et al. proposed that the potential candidates for a Rh SAC on ZrO 2 terrace sites are (RhO) ads and (RhOH) ads species [39] . The presence of multiple speciations in heterogeneous samples complicates the interpretation of spectroscopic data that contain information about structural/compositional speciations that emerge as averages over the larger volume of the sample.…”

Section: Properties and Approaches To Their Characterizationmentioning

confidence: 99%

Single Atom Catalysts: A Review of Characterization Methods

Kottwitz

Wang

et al. 2021

Chemistry Methods

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Single atom catalysts (SACs) harbor a potential to exceed nanoparticle catalysts in terms of activity, stability and selectivity in a growing number of chemical reactions. Although their investigation is attracting significant attention, important fundamental questions focusing on key physicochemical properties of SACs (e. g., structure -property relationships, structural dynamics, reaction-driven restructuring) remain unanswered. A main challenge for research in the field is how to reliably characterize the environments of single atoms in the presence of complicating factors such as low weight loadings, strong metal-support interactions, and atomic and multiscale hetero-geneity of bonding in the single atom sites. This review addresses this challenge -identifying catalytically relevant features of physicochemical properties of single atoms (charge state, electronic structure, atomic configuration, bonding interactions with a support) and surveying advanced tools/methods for characterizing them. The review places a strong emphasis on multimodal methods exploiting X-ray absorption, emission and photoelectron spectroscopies, and provides several examples from the authors' research that demonstrate their use as powerful tools for SAC characterization.

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“…Recently we have studied the nature of isolated Rh, Ru and Pt species deposited on two representative oxide surfaces, anatase TiO 2 (a reducible oxide), and tetragonal ZrO 2 (a non-reducible oxide) [5][6][7][8][9]. These systems have been characterized experimentally using high-resolution scanning transmission electron microscopy (STEM), Fourier transform infrared spectroscopy (FTIR), and temperature programmed desorption (TPD) spectra of adsorbed CO probe molecules.…”

Section: Introductionmentioning

confidence: 99%

Vibrational Properties of CO Adsorbed on Au Single Atom Catalysts on TiO2(101), ZrO2(101), CeO2(111), and LaFeO3(001) Surfaces: A DFT Study

et al. 2021

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The nature and local environment of Au single atoms supported and stabilized on four different oxides is studied by means of DFT + U calculations using CO as probe molecule and its stretching frequency, ωe, as a fingerprint of the site where the Au atom is bound. Four oxides are considered, anatase TiO2, tetragonal ZrO2, cubic CeO2, and a perovskite LaFeO3. In this latter case a recently reported experimental study has detected a stretching mode for CO adsorbed on Au1/LaFeO3 of 2215 cm−1, with a large blue shift, ∆ω(CO) = 72 cm−1 with respect to free CO. In order to identify the Au adsorption site that can give rise to this large blue-shift we have considered five cases: (a) Au replacing a lattice cation, (Au)subM; (b) Au replacing a lattice O anion, (Au)subO; (c) Au adsorbed on the surface, (Au)ads; (d) Au bound to an extra O atom on the surface, (AuO)ads, or (e) Au bound to two extra O atoms on the surface, (AuO2)ads. It turns out that the correct reproduction of ∆ω for CO adsorbed on positively charged gold, Auδ+, is challenging for DFT. Therefore, we have performed a comparative study of Auδ+-CO molecular compounds for which ωe(CO) is known experimentally using various kinds of DFT functionals and accurate CCSD and CCSD(T) quantum chemistry methods. Also based on this comparison we propose a tentative assignment for the observed frequency of CO adsorbed on Au1/LaFeO3 single atom catalyst. Graphic Abstract

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On the Real Nature of Rh Single‐Atom Catalysts Dispersed on the ZrO₂ Surface

Cited by 25 publications

References 64 publications

Oxygen-deficient metal oxides supported nano-intermetallic InNi ₃ C _0.5 toward efficient CO ₂ hydrogenation to methanol

Oxygen-deficient metal oxides supported nano-intermetallic InNi ₃ C _0.5 toward efficient CO ₂ hydrogenation to methanol

Single Atom Catalysts: A Review of Characterization Methods

Vibrational Properties of CO Adsorbed on Au Single Atom Catalysts on TiO2(101), ZrO2(101), CeO2(111), and LaFeO3(001) Surfaces: A DFT Study

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On the Real Nature of Rh Single‐Atom Catalysts Dispersed on the ZrO2 Surface

Cited by 25 publications

References 64 publications

Oxygen-deficient metal oxides supported nano-intermetallic InNi 3 C 0.5 toward efficient CO 2 hydrogenation to methanol

Oxygen-deficient metal oxides supported nano-intermetallic InNi 3 C 0.5 toward efficient CO 2 hydrogenation to methanol

Single Atom Catalysts: A Review of Characterization Methods

Vibrational Properties of CO Adsorbed on Au Single Atom Catalysts on TiO2(101), ZrO2(101), CeO2(111), and LaFeO3(001) Surfaces: A DFT Study

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On the Real Nature of Rh Single‐Atom Catalysts Dispersed on the ZrO₂ Surface

Oxygen-deficient metal oxides supported nano-intermetallic InNi ₃ C _0.5 toward efficient CO ₂ hydrogenation to methanol

Oxygen-deficient metal oxides supported nano-intermetallic InNi ₃ C _0.5 toward efficient CO ₂ hydrogenation to methanol