Oxidation of Reduced Ceria by Incorporation of Hydrogen

Li, Zhaorui; Werner, Kristin; Qian, Kun; You, Rui; Płucienik, Agata; Jia, Aiping; Wu, Liang; Zhang, Liyuan; Pan, Haibin; Kuhlenbeck, Helmut; Shaikhutdinov, Shamil K.; Huang, Weixin; Freund, Hans‐Joachim

doi:10.1002/ange.201907117

Cited by 29 publications

(22 citation statements)

References 55 publications

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“…The dashed lines shown in Figure c show the characteristic peaks for a Ce 3+ state. The degree of surface reduction [Ce 3+ /(Ce 4+ +Ce 3+ )] is estimated to be around 20 %, which is equivalent to about 10 % of the oxygen sites being vacant (note that one oxygen vacancy creates two Ce 3+ ions) . The weak signal at 531.8 eV in the O 1s XP spectrum of CeO 2− x (111) was previously attributed to the oxygen anions near the oxygen vacancy (Figure d) .…”

Section: Figurementioning

confidence: 90%

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Water‐Assisted Homolytic Dissociation of Propyne on a Reduced Ceria Surface

et al. 2020

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The emergence of ceria (CeO2) as an efficient catalyst for the selective hydrogenation of alkynes has attracted great attention. Intensive research effort has been devoted to understanding the underlying catalytic mechanism, in particular the H2–CeO2 interaction. Herein, we show that the adsorption of propyne (C3H4) on ceria, another key aspect in the hydrogenation of propyne to propene, strongly depends on the degree of reduction of the ceria surface and hydroxylation of the surface, as well as the presence of water. The dissociation of propyne and the formation of methylacetylide (CH3CC‐) have been identified through the combination of infrared reflection absorption spectroscopy (IRAS) and DFT calculations. We demonstrate that propyne undergoes heterolytic dissociation on the reduced ceria surface by forming a methylacetylide ion on the oxygen vacancy site and transferring a proton to the nearby oxygen site (OH group), while a water molecule that competes with the chemisorbed methylacetylide at the vacancy site assists the homolytic dissociation pathway by rebounding the methylacetylide to the nearby oxygen site.

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Section: Figurementioning

confidence: 90%

“…Both oxidized stoichiometric CeO 2 (111) and reduced CeO 2− x (111) ceria films were fabricated on Ru(0001) substrates . The surface crystal structures and the electronic structures of these ceria films were characterized by low‐energy electron diffraction (LEED) and X‐ray photoelectron spectroscopy (XPS; Figure a–d).…”

Section: Figurementioning

confidence: 99%

Water‐Assisted Homolytic Dissociation of Propyne on a Reduced Ceria Surface

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“…Generally speaking, the existence of oxygen vacancy is accompanied by the change of valence of metal elements (the formation of low‐valent metal ions), so the existence and semi‐quantitative analysis of surface oxygen vacancies can be judged and calculated by XPS datum. [ 63 ]…”

Section: Characterization Of Oxygen Defects In Nanostructured Metal Oxidesmentioning

confidence: 99%

Oxygen Defects in Nanostructured Metal‐Oxide Gas Sensors: Recent Advances and Challenges^†

Ding

Liu

et al. 2020

Chin. J. Chem.

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Defect engineering has been the most promising strategy to modulate the surface microstructure and electronic structure of the metal oxides, which will govern the efficiency of a given oxide for the applications in heterogeneous catalysis, energy storage and conversion fields, and gas sensing. This review summarizes recent research advances on understanding the role of oxygen vacancies of the metal oxides in gas sensing. First, different strategies for oxygen vacancy productions are summarized and compared. Then, the proper characterization techniques for oxygen vacancy are introduced. Importantly, the structure-activity relationships between vacancy engineering and gas sensing ability are further illustrated coupling the experimental results and theoretical studies. Finally, the key challenges and prospects regarding defect engineering in gas sensing are highlighted. Wenjie Ding (left) obtained his bachelor degree from Beijing Forestry University in 2018. Currently, he is pursuing his master degree under the supervision of Associate Professor Jiajia Liu in Beijing Instituted of Technology, China. His current research interests mainly focus on the synthesis of nanomaterials for the application of gas sensing. Dr. Jiajia Liu (middle) received her PhD degree in 2010 from Department of Chemical & Biomolecular Engineering of National University of Singapore, Singapore. Currently, she is Associate Professor in School of Materials and Engineering, Beijing Institute of Technology, China. Her current research interest is the development of metal oxide nanostructures and their applications in sensor, catalysis, and optoelectronics. Jiatao Zhang (right) was born in 1975. He earned his PhD from the Department of Chemistry, Tsinghua University, in 2006. Currently, he is Xu Teli Professor in the School of Materials and Engineering, BIT. He was awarded the Excellent Young Scientist foundation of NSFC in 2013. He also serves as the director of Beijing Key Laboratory of Construction-Tailorable Advanced Functional Materials and Green Applications. His current research interest is inorganic chemistry of semiconductor-based hybrid nanostructures with novel optical, electronic properties for the applications in energy conversion and storage, catalysis, optoelectronics and biology.

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“…Sowohl vollständig oxidierte (d.h. stöchiometrische) CeO 2 (111)‐, als auch reduzierte CeO 2− x (111)‐Filme wurden auf einem Ru(0001)‐Substrat gewachsen . Die Oberflächenkristallstruktur und elektronische Struktur dieser Ceroxidfilme wurde jeweils durch Low‐Energy‐Electron‐Diffraction (LEED) und Röntgen‐Photoelektronenspektroskopie (XPS) charakterisiert (siehe Abbildung a–d).…”

Section: Figureunclassified

“…20 % geschätzt, was einer Sauerstoffleerstellenkonzentration von ≈10 % bezüglich aller Sauerstoffpositionen von CeO 2 (111) entspricht. (Es sei hier darauf hingewiesen, dass die Bildung einer Sauerstoffleerstelle auch zwei Ce 3+ ‐Ionen erzeugt) . Das schwache Signal bei 531.8 eV im O 1s XP‐Spektrum von CeO 2− x (111) wurde bisher Sauerstoffanionen in der Nähe einer Sauerstoffleerstelle zugeschrieben (Abbildung d) .…”

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Wasserunterstützte homolytische Dissoziation von Propin auf reduzierter Ceroxidoberfläche

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Die neuartige Verwendung von Ceroxid (CeO2) als effizienter Katalysator für die selektive Hydrierung von Alkinen hat große Aufmerksamkeit erregt. Intensive Forschungsanstrengungen wurden dem Verständnis des zugrundeliegenden katalytischen Mechanismus gewidmet, insbesondere der Wechselwirkung zwischen H2 und CeO2. In dieser Arbeit zeigen wir, dass ein weiterer Schlüsselaspekt der Hydrierungsreaktion von Propin (C3H4) zu Propen – die Adsorption von Propin auf Ceroxid – stark vom Reduktionsgrad der Ceroxidoberfläche, vom Hydroxylierungsgrad der Oberfläche und von der Gegenwart von Wasser abhängt. Durch die Kombination von Infrarot‐Reflexions‐Absorptions‐Spektroskopie (IRAS) und Dichtefunktionaltheorie(DFT)‐Rechnungen wurde die Dissoziation von Propin nachverfolgt und die Bildung von Methylacetylidgruppen (CH3CC‐) nachgewiesen. Wir zeigen, dass Propin auf der reduzierten Ceroxidoberfläche heterolytisch dissoziiert, wenn ein Methylacetylid‐Ion auf einer Sauerstoffleerstelle gebildet werden kann und ein Proton auf eine nahgelegene Sauerstoffstelle (OH‐Gruppe) übertragen wird, während die Anwesenheit von Wassermolekülen, mit denen das chemisorbierte Methylacetylid um die Leerstelle konkurriert, durch Verdrängung des Methylacetylids auf die nahe gelegene Sauerstoffstelle den homolytischen Dissoziationsweg begünstigt.

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Oxidation of Reduced Ceria by Incorporation of Hydrogen

Cited by 29 publications

References 55 publications

Water‐Assisted Homolytic Dissociation of Propyne on a Reduced Ceria Surface

Water‐Assisted Homolytic Dissociation of Propyne on a Reduced Ceria Surface

Oxygen Defects in Nanostructured Metal‐Oxide Gas Sensors: Recent Advances and Challenges^†

Wasserunterstützte homolytische Dissoziation von Propin auf reduzierter Ceroxidoberfläche

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Oxidation of Reduced Ceria by Incorporation of Hydrogen

Cited by 29 publications

References 55 publications

Water‐Assisted Homolytic Dissociation of Propyne on a Reduced Ceria Surface

Water‐Assisted Homolytic Dissociation of Propyne on a Reduced Ceria Surface

Oxygen Defects in Nanostructured Metal‐Oxide Gas Sensors: Recent Advances and Challenges†

Wasserunterstützte homolytische Dissoziation von Propin auf reduzierter Ceroxidoberfläche

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Oxygen Defects in Nanostructured Metal‐Oxide Gas Sensors: Recent Advances and Challenges^†