Review: monoclinic zirconia, its surface sites and their interaction with carbon monoxide

Kouva, Sonja; Honkala, Karoliina; Lefferts, Leon; Kanervo, Jaana

doi:10.1039/c5cy00330j

Cited by 145 publications

(154 citation statements)

References 93 publications

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“…The bands are red-shifted to 3700 and 3610 cm −1 , and these wavenumbers therefore represent the first surface near layer (consisting of OH and an ice-like-structured water molecule network). This is supported by the ZrO 2 review of Kouva et al 23 but also by studies on other oxides like Fe 2 O 3 29 or TiO 2 . 24,30 The broad feature between ∼3600−2800 cm −1 can subsequently be referred to as H-bonded water and, thus, both the ice-like layer and polymeric chained water, with a comparably low impact of the oxide surface.…”

Section: Acs Applied Materials and Interfacesmentioning

confidence: 64%

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Structural and Electrochemical Properties of Physisorbed and Chemisorbed Water Layers on the Ceramic Oxides Y₂O₃, YSZ, and ZrO₂

Köck

Kogler

Klötzer

et al. 2016

ACS Appl. Mater. Interfaces

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A combination of operando Fourier transform infrared spectroscopy, operando electrochemical-impedance spectroscopy, and moisture-sorption measurements has been exploited to study the adsorption and conduction behavior of H2O and D2O on the technologically important ceramic oxides YSZ (8 mol % Y2O3), ZrO2, and Y2O3. Because the characterization of the chemisorbed and physisorbed water layers is imperative to a full understanding of (electro-)catalytically active doped oxide surfaces and their application in technology, the presented data provide the specific reactivity of these oxides toward water over a pressure-and-temperature parameter range extending up to, e.g., solid-oxide fuel cell (SOFC)-relevant conditions. The characteristic changes of the related infrared bands could directly be linked to the associated conductivity and moisture-sorption data. For YSZ, a sequential dissociative water ("ice-like" layer) and polymeric chained water ("liquid-like") water-adsorption model for isothermal and isobaric conditions over a pressure range of 10(-5) to 24 mbar and a temperature range from room temperature up to 1173 K could be experimentally verified. On pure monoclinic ZrO2, in contrast to highly hydroxylated YSZ and Y2O3, a high surface concentration of OH groups from water chemisorption is absent at any temperature and pressure. Thus, the ice-like and following molecular water layers exhibit no measurable protonic conduction. We show that the water layers, even under these rather extreme experimental conditions, play a key role in understanding the function of these materials. Furthermore, the reported data are supposed to provide an extended basis for the further investigation of close-to-real gas adsorption or catalyzed heterogeneous reactions.

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Section: Acs Applied Materials and Interfacesmentioning

confidence: 64%

“…23 This paper hence tries to establish a basis for further SOFC-related water-adsorption studies on the examined "real" powder oxides.…”

Section: Acs Applied Materials and Interfacesmentioning

confidence: 99%

Structural and Electrochemical Properties of Physisorbed and Chemisorbed Water Layers on the Ceramic Oxides Y₂O₃, YSZ, and ZrO₂

Köck

Kogler

Klötzer

et al. 2016

ACS Appl. Mater. Interfaces

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“…In general, zirconia (ZrO 2 ) is not considered for sunlight absorption as it is a semiconductor with a wide band gap of around 5 eV and absorbs only ultraviolet (UV) light although ZrO 2 -based materials have promising application in several fields like thermal coating, optical coating, sensor, catalysis, energy conversion and storage, and biomedical applications12345678910111213.…”

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confidence: 99%

Oxygen-Deficient Zirconia (ZrO2−x): A New Material for Solar Light Absorption

Sinhamahapatra

Jeon

Kang

et al. 2016

Sci Rep

271

166

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Here, we present oxygen-deficient black ZrO2−x as a new material for sunlight absorption with a low band gap around ~1.5 eV, via a controlled magnesiothermic reduction in 5% H2/Ar from white ZrO2, a wide bandgap(~5 eV) semiconductor, usually not considered for solar light absorption. It shows for the first time a dramatic increase in solar light absorbance and significant activity for solar light-induced H2 production from methanol-water with excellent stability up to 30 days while white ZrO2 fails. Generation of large amounts of oxygen vacancies or surface defects clearly visualized by the HR-TEM and HR-SEM images is the main reason for the drastic alteration of the optical properties through the formation of new energy states near valence band and conduction band towards Fermi level in black ZrO2−x as indicated by XPS and DFT calculations of black ZrO2−x. Current reduction method using Mg and H2 is mild, but highly efficient to produce solar light-assisted photocatalytically active black ZrO2−x.

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“…Due to its unique properties, zirconia acts as a heterogeneous support and a catalyst component in multiple important processes for obtaining sustainable chemicals, as has been highlighted in the recent reviews and reports. [17,21,4,26,25,11,37] Moreover, zirconia finds its applications in, for instance, solid oxide fuel cells [32] and electrochemical sensors. [22] Zirconia exists in several polymorphic modifications, among which monoclinic (m), tetragonal (t), and cubic (c) are the most common examples.…”

Section: Introductionmentioning

confidence: 99%

Understanding Structure and Stability of Monoclinic Zirconia Surfaces from First-Principles Calculations

Bazhenov

Honkala

2016

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Under the water-rich pre-treatment and/or reaction conditions, structure and chemistry of the monoclinic zirconia surfaces are strongly influenced by oxygen vacancies and incorporated water. Here, we report a combined first-principles and atomistic thermodynamics study on the structure and stability of selected surfaces of the monoclinic zirconia. Our results indicate that among the studied surfaces, the most stable (111) surface is the least vulnerable towards oxygen vacancies in contrast to the less stable (011) and (101) surfaces, where formation of oxygen vacancies is energetically more favorable. Furthermore, we present a vigorous, systematic screening of water incorporation onto the studied surfaces. We observe that the greatest stabilization of the surfaces is achieved when a part of the adsorbed water molecules is dissociated. Nevertheless, the importance of water dissociation for achieving the greatest stabilization is high for the less stable (011) and (101) surfaces, while completely hydrated (111) surface is stabilized equally regardless of the water dissociation state. Analysis of the constructed phase diagrams reveals that the (111) surface remains preferably clean and the (011) and (101) surfaces have dissociated water at low coverage under the reactive conditions of T = 600-900 K and p(H 2 O) < 1 bar. Upon temperature decrease and/or pressure increase, all studied surfaces gradually uptake water until fully hydrated. All in all, our findings complement and broaden the existing picture of the structure and stability of the monoclinic zirconia surfaces under the pre-treatment and/or reaction conditions, enabling rationalization of the potential roles of zirconia as a heterogeneous support and a catalyst component.

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Review: monoclinic zirconia, its surface sites and their interaction with carbon monoxide

Abstract: This review is focused on the surface sites of monoclinic zirconia, especially surface hydroxyls and their manipulation, and the interaction of CO with zirconia to form linearly adsorbed CO and formates.

Cited by 145 publications

References 93 publications

Structural and Electrochemical Properties of Physisorbed and Chemisorbed Water Layers on the Ceramic Oxides Y₂O₃, YSZ, and ZrO₂

Structural and Electrochemical Properties of Physisorbed and Chemisorbed Water Layers on the Ceramic Oxides Y₂O₃, YSZ, and ZrO₂

Oxygen-Deficient Zirconia (ZrO2−x): A New Material for Solar Light Absorption

Understanding Structure and Stability of Monoclinic Zirconia Surfaces from First-Principles Calculations

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Review: monoclinic zirconia, its surface sites and their interaction with carbon monoxide

Abstract: This review is focused on the surface sites of monoclinic zirconia, especially surface hydroxyls and their manipulation, and the interaction of CO with zirconia to form linearly adsorbed CO and formates.

Cited by 145 publications

References 93 publications

Structural and Electrochemical Properties of Physisorbed and Chemisorbed Water Layers on the Ceramic Oxides Y2O3, YSZ, and ZrO2

Structural and Electrochemical Properties of Physisorbed and Chemisorbed Water Layers on the Ceramic Oxides Y2O3, YSZ, and ZrO2

Oxygen-Deficient Zirconia (ZrO2−x): A New Material for Solar Light Absorption

Understanding Structure and Stability of Monoclinic Zirconia Surfaces from First-Principles Calculations

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Structural and Electrochemical Properties of Physisorbed and Chemisorbed Water Layers on the Ceramic Oxides Y₂O₃, YSZ, and ZrO₂

Structural and Electrochemical Properties of Physisorbed and Chemisorbed Water Layers on the Ceramic Oxides Y₂O₃, YSZ, and ZrO₂