1
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Acetone to isobutene conversion on ZnxTiyOz: Effects of TiO2 facet. J Catal 2022. [DOI: 10.1016/j.jcat.2022.03.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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2
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Williams OBJ, Katsiev K, Baek B, Harrison G, Thornton G, Idriss H. Direct Visualization of a Gold Nanoparticle Electron Trapping Effect. J Am Chem Soc 2022; 144:1034-1044. [PMID: 34985273 DOI: 10.1021/jacs.1c12197] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
A new atomic-scale anisotropy in the photoreaction of surface carboxylates on rutile TiO2(110) induced by gold clusters is found. STM and DFT+U are used to study this phenomenon by monitoring the photoreaction of a prototype hole-scavenger molecule, benzoic acid, over stoichiometric (s) s-TiO2, Au9/s-TiO2, and reduced (r) Au9/r-TiO2. STM results show that benzoic acid adsorption displaces a large fraction of Au clusters from the terraces toward their edges. DFT calculations explain that Au9 clusters on stoichiometric TiO2 are distorted by benzoic acid adsorption. The influence of sub-monolayers of Au on the UV/visible photoreaction of benzoic acid was explored at room temperature, with adsorbate depletion taken as a measure of activity. The empty sites, observed upon photoexcitation, occurred in elongated chains (2 to 6 molecules long) in the [11̅0] and [001] directions. A roughly 3-fold higher depletion rate is observed in the [001] direction. This is linked to the anisotropic conduction of excited electrons along [001], with subsequent trapping by Au clusters leaving a higher concentration of holes and thus an increased decomposition rate. To our knowledge this is the first time that atomic-scale directionality of a chemical reaction is reported upon photoexcitation of the semiconductor.
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Affiliation(s)
- Oscar Bentley Jerdmyr Williams
- Department of Chemistry and London Centre for Nanotechnology (LCN), University College London (UCL), WC1H 0AH, London, U.K
| | - Khabiboulakh Katsiev
- Surface Science and Advanced Characterisation, SABIC-CRD at King Abdullah University for Science and Technology (KAUST), Thuwal, 23955, Saudi Arabia
| | - Byeongjin Baek
- SABIC Global Corporate Research, Sugar Land, Texas 77478, United States
| | - George Harrison
- KAUST Solar Center (KSC), Physical Sciences and Engineering Division (PSE), King Abdullah University for Science and Technology (KAUST), Thuwal, 23955, Saudi Arabia
| | - Geoff Thornton
- Department of Chemistry and London Centre for Nanotechnology (LCN), University College London (UCL), WC1H 0AH, London, U.K
| | - Hicham Idriss
- Department of Chemistry and London Centre for Nanotechnology (LCN), University College London (UCL), WC1H 0AH, London, U.K.,Surface Science and Advanced Characterisation, SABIC-CRD at King Abdullah University for Science and Technology (KAUST), Thuwal, 23955, Saudi Arabia
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3
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Kräuter J, Franz E, Waidhas F, Brummel O, Jörg Libuda, Al-Shamery K. The Role of Defects in the Photoconversion of 2-Propanol on Rutile Titania: Operando Spectroscopy Combined with Elementary Studies. J Catal 2022. [DOI: 10.1016/j.jcat.2021.12.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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4
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Kräuter J, Al-Shamery K. Bulk defect-dependent initial steps of acetone oxidation on rutile TiO2(110). Mol Phys 2021. [DOI: 10.1080/00268976.2021.1963870] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Jessica Kräuter
- Institute for Chemistry, Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
| | - Katharina Al-Shamery
- Institute for Chemistry, Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
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5
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Hwang SI, Chen HY, Fenk C, Rothfuss MA, Bocan KN, Franconi NG, Morgan GJ, White DL, Burkert SC, Ellis JE, Vinay ML, Rometo DA, Finegold DN, Sejdic E, Cho SK, Star A. Breath Acetone Sensing Based on Single-Walled Carbon Nanotube-Titanium Dioxide Hybrids Enabled by a Custom-Built Dehumidifier. ACS Sens 2021; 6:871-880. [PMID: 33720705 DOI: 10.1021/acssensors.0c01973] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Acetone is a metabolic byproduct found in the exhaled breath and can be measured to monitor the metabolic degree of ketosis. In this state, the body uses free fatty acids as its main source of fuel because there is limited access to glucose. Monitoring ketosis is important for type I diabetes patients to prevent ketoacidosis, a potentially fatal condition, and individuals adjusting to a low-carbohydrate diet. Here, we demonstrate that a chemiresistor fabricated from oxidized single-walled carbon nanotubes functionalized with titanium dioxide (SWCNT@TiO2) can be used to detect acetone in dried breath samples. Initially, due to the high cross sensitivity of the acetone sensor to water vapor, the acetone sensor was unable to detect acetone in humid gas samples. To resolve this cross-sensitivity issue, a dehumidifier was designed and fabricated to dehydrate the breath samples. Sensor response to the acetone in dried breath samples from three volunteers was shown to be linearly correlated with the two other ketone bodies, acetoacetic acid in urine and β-hydroxybutyric acid in the blood. The breath sampling and analysis methodology had a calculated acetone detection limit of 1.6 ppm and capable of detecting up to at least 100 ppm of acetone, which is the dynamic range of breath acetone for someone with ketosis. Finally, the application of the sensor as a breath acetone detector was studied by incorporating the sensor into a handheld prototype breathalyzer.
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Affiliation(s)
- Sean I. Hwang
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Hou-Yu Chen
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Courtney Fenk
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Michael A. Rothfuss
- Department of Electrical and Computer Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Kara N. Bocan
- Department of Electrical and Computer Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Nicholas G. Franconi
- Department of Electrical and Computer Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Gregory J. Morgan
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - David L. White
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Seth C. Burkert
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - James E. Ellis
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Miranda L. Vinay
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - David A. Rometo
- Department of Endocrinology, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, United States
| | - David N. Finegold
- Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Ervin Sejdic
- Department of Electrical and Computer Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Sung Kwon Cho
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Alexander Star
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
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6
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Padayachee D, Mahomed AS, Singh S, Friedrich HB. Effect of the TiO2 Anatase/Rutile Ratio and Interface for the Oxidative Activation of n-Octane. ACS Catal 2020. [DOI: 10.1021/acscatal.9b04004] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Drushan Padayachee
- School of Chemistry and Physics, University of KwaZulu-Natal, Durban 4000, South Africa
| | - Abdul S. Mahomed
- School of Chemistry and Physics, University of KwaZulu-Natal, Durban 4000, South Africa
| | - Sooboo Singh
- School of Chemistry and Physics, University of KwaZulu-Natal, Durban 4000, South Africa
| | - Holger B. Friedrich
- School of Chemistry and Physics, University of KwaZulu-Natal, Durban 4000, South Africa
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7
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Li H, Sun J, Li G, Wu D, Wang Y. Real-time monitoring of surface acetone enolization and aldolization. Catal Sci Technol 2020. [DOI: 10.1039/c9cy02339a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Real-time DRIFTS reveals the formation of acetone enolate and its subsequent aldolization via an Eley–Rideal type mechanism on Zn1Zr10Oz.
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Affiliation(s)
- Houqian Li
- The Gene & Linda Voiland School of Chemical Engineering and Bioengineering
- Washington State University
- Pullman
- USA
| | - Junming Sun
- The Gene & Linda Voiland School of Chemical Engineering and Bioengineering
- Washington State University
- Pullman
- USA
| | - Gengnan Li
- The Gene & Linda Voiland School of Chemical Engineering and Bioengineering
- Washington State University
- Pullman
- USA
| | - Di Wu
- The Gene & Linda Voiland School of Chemical Engineering and Bioengineering
- Washington State University
- Pullman
- USA
- Alexandra Navrotsky Institute for Experimental Thermodynamics
| | - Yong Wang
- The Gene & Linda Voiland School of Chemical Engineering and Bioengineering
- Washington State University
- Pullman
- USA
- Institute for Integrated Catalysis
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8
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Muraca AR, Kershis MD, Camillone N, White MG. Ultrafast dynamics of acetone photooxidation on TiO2(110). J Chem Phys 2019; 151:161103. [DOI: 10.1063/1.5122269] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Amanda R. Muraca
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794, USA
| | - Matthew D. Kershis
- Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Nicholas Camillone
- Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Michael G. White
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794, USA
- Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973, USA
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9
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Switch in photocatalytic reaction selectivity: The effect of oxygen partial pressure on carbon-carbon bond dissociation over hydroxylated TiO2(1 1 0) surfaces. J Catal 2018. [DOI: 10.1016/j.jcat.2018.04.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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10
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Walenta CA, Kollmannsberger SL, Courtois C, Tschurl M, Heiz U. Photocatalytic selectivity switch to C–C scission: α-methyl ejection oftert-butanol on TiO2(110). Phys Chem Chem Phys 2018; 20:7105-7111. [DOI: 10.1039/c8cp00223a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The thermal and photochemical mechanistic pathways for tertiary alcohols on the rutile TiO2(110)-surface are studied with the example oftert-butanol.
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Affiliation(s)
- Constantin A. Walenta
- Chair of Physical Chemistry
- Department of Chemistry and Catalysis Research Center
- Technische Universität München
- 85748 Garching
- Germany
| | - Sebastian L. Kollmannsberger
- Chair of Physical Chemistry
- Department of Chemistry and Catalysis Research Center
- Technische Universität München
- 85748 Garching
- Germany
| | - Carla Courtois
- Chair of Physical Chemistry
- Department of Chemistry and Catalysis Research Center
- Technische Universität München
- 85748 Garching
- Germany
| | - Martin Tschurl
- Chair of Physical Chemistry
- Department of Chemistry and Catalysis Research Center
- Technische Universität München
- 85748 Garching
- Germany
| | - Ueli Heiz
- Chair of Physical Chemistry
- Department of Chemistry and Catalysis Research Center
- Technische Universität München
- 85748 Garching
- Germany
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11
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Wang Y, Wöll C. IR spectroscopic investigations of chemical and photochemical reactions on metal oxides: bridging the materials gap. Chem Soc Rev 2017; 46:1875-1932. [DOI: 10.1039/c6cs00914j] [Citation(s) in RCA: 130] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
In this review, we highlight recent progress (2008–2016) in infrared reflection absorption spectroscopy (IRRAS) studies on oxide powders achieved by using different types of metal oxide single crystals as reference systems.
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Affiliation(s)
- Yuemin Wang
- Institute of Functional Interfaces
- Karlsruhe Institute of Technology
- Eggenstein-Leopoldshafen
- Germany
| | - Christof Wöll
- Institute of Functional Interfaces
- Karlsruhe Institute of Technology
- Eggenstein-Leopoldshafen
- Germany
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12
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Xu C, Yang W, Guo Q, Dai D, Yang X. Photoinduced decomposition of acetaldehyde on a reduced TiO2(110) surface: involvement of lattice oxygen. Phys Chem Chem Phys 2016; 18:30982-30989. [DOI: 10.1039/c6cp04397f] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A simple model reveals that BBO atoms are involved in the photo-induced decomposition of CH3CHO on TiO2(110).
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Affiliation(s)
- Chenbiao Xu
- State Key Laboratory of Molecular Reaction Dynamics
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian 116023
- P. R. China
| | - Wenshao Yang
- State Key Laboratory of Molecular Reaction Dynamics
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian 116023
- P. R. China
| | - Qing Guo
- State Key Laboratory of Molecular Reaction Dynamics
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian 116023
- P. R. China
| | - Dongxu Dai
- State Key Laboratory of Molecular Reaction Dynamics
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian 116023
- P. R. China
| | - Xueming Yang
- State Key Laboratory of Molecular Reaction Dynamics
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian 116023
- P. R. China
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13
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Guo Q, Zhou C, Ma Z, Ren Z, Fan H, Yang X. Elementary photocatalytic chemistry on TiO2surfaces. Chem Soc Rev 2016; 45:3701-30. [DOI: 10.1039/c5cs00448a] [Citation(s) in RCA: 250] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
In this article, we review the recent advances in the photoreactions of small molecules with model TiO2surfaces, and propose a photocatalytical model based on nonadiabatic dynamics and ground state surface reactions.
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Affiliation(s)
- Qing Guo
- State Key Laboratory of Molecular Reaction Dynamics
- Dalian Institute of Chemical Physics
- Dalian 116023
- P. R. China
| | - Chuanyao Zhou
- State Key Laboratory of Molecular Reaction Dynamics
- Dalian Institute of Chemical Physics
- Dalian 116023
- P. R. China
| | - Zhibo Ma
- State Key Laboratory of Molecular Reaction Dynamics
- Dalian Institute of Chemical Physics
- Dalian 116023
- P. R. China
| | - Zefeng Ren
- International Center for Quantum Materials and School of Physics
- Peking University
- Beijing
- P. R. China
- Collaborative Innovation Center of Quantum Matter
| | - Hongjun Fan
- State Key Laboratory of Molecular Reaction Dynamics
- Dalian Institute of Chemical Physics
- Dalian 116023
- P. R. China
| | - Xueming Yang
- State Key Laboratory of Molecular Reaction Dynamics
- Dalian Institute of Chemical Physics
- Dalian 116023
- P. R. China
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14
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15
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Lüken A, Muhler M, Strunk J. On the role of gold nanoparticles in the selective photooxidation of 2-propanol over Au/TiO2. Phys Chem Chem Phys 2015; 17:10391-7. [DOI: 10.1039/c4cp05423g] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Partial insight into the reaction mechanism of the photooxidation of 2-propanol over Au/TiO2. 2-Propanol is activated by hole capture and converted to acetone requiring the presence of O2 as an electron acceptor. The deposited Au nanoparticles are assumed to facilitate the electron transfer from the TiO2 conduction band to adsorbed O2.
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Affiliation(s)
- Alexander Lüken
- Laboratory of Industrial Chemistry
- Ruhr-University Bochum
- 44801 Bochum
- Germany
| | - Martin Muhler
- Laboratory of Industrial Chemistry
- Ruhr-University Bochum
- 44801 Bochum
- Germany
| | - Jennifer Strunk
- Laboratory of Industrial Chemistry
- Ruhr-University Bochum
- 44801 Bochum
- Germany
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16
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17
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Clawin PM, Friend CM, Al-Shamery K. Defects in surface chemistry--reductive coupling of benzaldehyde on rutile TiO₂(110). Chemistry 2014; 20:7665-9. [PMID: 24825761 DOI: 10.1002/chem.201402102] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Indexed: 11/11/2022]
Abstract
The surface chemistry of oxygen and oxygenates on Rutile TiO2(110) is of great interest for various applications such as heterogeneous catalysis and photo catalysis. Though it is generally accepted that surface defects are active sites, the role of subsurface defects is under debate. We have therefore investigated the influence of the bulk defect density on the reductive coupling of benzaldehyde to stilbene as a model system. Using IRRAS we identify stilbene diolate as a reduction intermediate. The concentration of this intermediate is proportional to the bulk defect density, whereas adsorption of benzaldehyde at lower temperatures is not affected, which indicates a dominant role of Ti interstitials at temperatures above 400 K.
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Affiliation(s)
- Peter M Clawin
- Institute for Chemistry, Carl von Ossietzky University of Oldenburg, Carl von Ossietzky Strasse 9-11, 26129 Oldenburg (Germany), Fax: (+49) 441 709 2809
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18
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Pham TN, Shi D, Resasco DE. Reaction kinetics and mechanism of ketonization of aliphatic carboxylic acids with different carbon chain lengths over Ru/TiO2 catalyst. J Catal 2014. [DOI: 10.1016/j.jcat.2014.04.008] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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19
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Kohtani S, Kamoi Y, Yoshioka E, Miyabe H. Kinetic study on photocatalytic hydrogenation of acetophenone derivatives on titanium dioxide. Catal Sci Technol 2014. [DOI: 10.1039/c3cy00879g] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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20
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21
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Jensen SC, Friend CM. The Dynamic Roles of Interstitial and Surface Defects on Oxidation and Reduction Reactions on Titania. Top Catal 2013. [DOI: 10.1007/s11244-013-0135-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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22
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Kershis MD, Wilson DP, White MG. Dynamics of acetone photooxidation on TiO2(110): State-resolved measurements of methyl photoproducts. J Chem Phys 2013; 138:204703. [DOI: 10.1063/1.4805065] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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23
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Henderson MA, Lyubinetsky I. Molecular-Level Insights into Photocatalysis from Scanning Probe Microscopy Studies on TiO2(110). Chem Rev 2013; 113:4428-55. [DOI: 10.1021/cr300315m] [Citation(s) in RCA: 204] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Michael A. Henderson
- Physical Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999,
MS K8-87 Richland, Washington 99352, United States
| | - Igor Lyubinetsky
- Environmental Molecular Sciences
Laboratory, Pacific Northwest National Laboratory, P.O. Box 999, MS K8-93 Richland, Washington 99352, United States
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24
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Campbell CT, Sellers JRV. Enthalpies and entropies of adsorption on well-defined oxide surfaces: experimental measurements. Chem Rev 2013; 113:4106-35. [PMID: 23441680 DOI: 10.1021/cr300329s] [Citation(s) in RCA: 130] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Charles T Campbell
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, USA.
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25
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Xia Y, Ye J, Murray P, Ali A, Ge Q, Zhang Z. Imaging reactions of acetone with oxygen adatoms on partially oxidized TiO2(110). Phys Chem Chem Phys 2013; 15:13897-901. [DOI: 10.1039/c3cp51695d] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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26
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27
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Kershis MD, White MG. Photooxidation of ethanol and 2-propanol on TiO2(110): evidence for methyl radical ejection. Phys Chem Chem Phys 2013; 15:17976-82. [DOI: 10.1039/c3cp53027b] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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28
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Jensen SC, Phillips KR, Baron M, Landis EC, Friend CM. Norrish Type I surface photochemistry for butyrophenone on TiO2(110). Phys Chem Chem Phys 2013; 15:5193-201. [DOI: 10.1039/c3cp44602f] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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29
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Smits M, Ling Y, Lenaerts S, Van Doorslaer S. Photocatalytic removal of soot: unravelling of the reaction mechanism by EPR and in situ FTIR spectroscopy. Chemphyschem 2012; 13:4251-7. [PMID: 23150192 DOI: 10.1002/cphc.201200674] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Revised: 10/19/2012] [Indexed: 11/07/2022]
Abstract
Photocatalytic soot oxidation is studied on P25 TiO(2) as an important model reaction for self-cleaning processes by means of electron paramagnetic resonance (EPR) and Fourier transform infrared (FTIR) spectroscopy. Contacting of carbon black with P25 leads on the one hand to a reduction of the local dioxygen concentration in the powder. On the other hand, the weakly adsorbed radicals on the carbon particles are likely to act as alternative traps for the photogenerated conduction-band electrons. We find furthermore that the presence of dioxygen and oxygen-related radicals is vital for the photocatalytic soot degradation. The complete oxidation of soot to CO(2) is evidenced by in situ FTIR spectroscopy, no intermediate CO is detected during the photocatalytic process.
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Affiliation(s)
- Marianne Smits
- Research group DuEL, Department of Bioscience-engineering, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerpen, Belgium
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30
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Plata JJ, Collico V, Márquez AM, Sanz JF. Analysis of the origin of lateral interactions in the adsorption of small organic molecules on oxide surfaces. Theor Chem Acc 2012. [DOI: 10.1007/s00214-012-1311-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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31
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Vohs JM. Site requirements for the adsorption and reaction of oxygenates on metal oxide surfaces. Chem Rev 2012. [PMID: 23181433 DOI: 10.1021/cr300328u] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- John M Vohs
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
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32
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Chen H, Nanayakkara CE, Grassian VH. Titanium Dioxide Photocatalysis in Atmospheric Chemistry. Chem Rev 2012; 112:5919-48. [DOI: 10.1021/cr3002092] [Citation(s) in RCA: 614] [Impact Index Per Article: 51.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Haihan Chen
- Departments
of Chemical and Biochemical Engineering and §Chemistry, University of Iowa, Iowa City, Iowa 52242, United States
| | - Charith E. Nanayakkara
- Departments
of Chemical and Biochemical Engineering and §Chemistry, University of Iowa, Iowa City, Iowa 52242, United States
| | - Vicki H. Grassian
- Departments
of Chemical and Biochemical Engineering and §Chemistry, University of Iowa, Iowa City, Iowa 52242, United States
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33
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Xia Y, Zhang B, Ye J, Ge Q, Zhang Z. Acetone-Assisted Oxygen Vacancy Diffusion on TiO2(110). J Phys Chem Lett 2012; 3:2970-2974. [PMID: 26292235 DOI: 10.1021/jz301293y] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We have studied the dynamic relationship between acetone and bridge-bonded oxygen (Ob) vacancy (VO) defect sites on the TiO2(110)-1 × 1 surface using scanning tunneling microscopy (STM) and density function theory (DFT) calculations. We report an adsorbate-assisted VO diffusion mechanism. The STM images taken at 300 K show that acetone preferably adsorbs on the VO site and is mobile. The sequential isothermal STM images directly show that the mobile acetone effectively migrates the position of VO by a combination of two acetone diffusion channels: one is the diffusion along the Ob row and moving as an alkyl group, which heals the initial VO; another is the diffusion from the Ob row to the five-coordinated Ti(4+) row and then moving along the Ti(4+) row as an acetone, which leaves a VO behind. The calculated acetone diffusion barriers for the two channels are comparable and agree with experimental results.
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Affiliation(s)
- Yaobiao Xia
- †Department of Physics, Baylor University, Waco, Texas 76798, United States
| | - Bo Zhang
- †Department of Physics, Baylor University, Waco, Texas 76798, United States
| | - Jingyun Ye
- §Department of Chemistry and Biochemistry, Southern Illinois University, Carbondale, Illinois 62901, United States
| | - Qingfeng Ge
- §Department of Chemistry and Biochemistry, Southern Illinois University, Carbondale, Illinois 62901, United States
| | - Zhenrong Zhang
- †Department of Physics, Baylor University, Waco, Texas 76798, United States
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34
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Calaza FC, Xu Y, Mullins DR, Overbury SH. Oxygen Vacancy-Assisted Coupling and Enolization of Acetaldehyde on CeO2(111). J Am Chem Soc 2012; 134:18034-45. [DOI: 10.1021/ja3074243] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Florencia C. Calaza
- Chemical
Sciences Division and ‡Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee
37831, United States
| | - Ye Xu
- Chemical
Sciences Division and ‡Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee
37831, United States
| | - David R. Mullins
- Chemical
Sciences Division and ‡Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee
37831, United States
| | - Steven H. Overbury
- Chemical
Sciences Division and ‡Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee
37831, United States
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35
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Benz L, Park A, Corey JR, Mezher MP, Park VC. Interaction of petroleum-relevant organosulfur compounds with TiO2(110). LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:10209-10216. [PMID: 22694143 DOI: 10.1021/la301811q] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The interaction of two sets of structurally related molecules, thiophenol/thioanisole, and thiophene/tetrahydrothiophene, with vacuum-annealed and ion-bombarded TiO(2)(110) surfaces has been studied using a combination of temperature-programmed reaction spectroscopy (TPRS) and X-ray photoelectron spectroscopy (XPS). All thioethers studied were observed to adsorb and desorb from both surfaces without producing reaction products, while thiophenol, the only species studied containing a S-H bond, reacted with both surfaces. Approximately 25% of surface bound thiophenol decomposed over the vacuum-annealed surface. On the bombarded surface, thiophenol both decomposed into surface-bound C(x)H(y)/S fragments, and reacted to form benzene, which desorbed from the surface at 400 K. We propose that phenylthiolate formation on the bombarded surface leads to the observed production of benzene. These results highlight the importance of defects in the reactivity of titania, and lay the foundation for the study of larger, refractory sulfur compounds present in fuel.
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Affiliation(s)
- Lauren Benz
- Department of Chemistry and Biochemistry, University of San Diego, San Diego, California 92110, United States.
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36
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Jensen SC, Shank A, Madix RJ, Friend CM. Butyrophenone on O-TiO2(110): one-dimensional motion in a weakly confined potential well. ACS NANO 2012; 6:2925-2930. [PMID: 22452747 DOI: 10.1021/nn300949q] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We demonstrate the one-dimensional confinement of weakly bound butyrophenone molecules between strongly bound complexes formed via reaction with oxygen on TiO(2)(110). Butyrophenone weakly bound to Ti rows through the carbonyl oxygen diffuses freely in one dimension along the rows even at 55 K, persisting for many minutes before hopping out of the 1-D well. Quantitative analysis yields an estimate of the migration barrier of 0.11 eV and a frequency factor of 6.5 × 10(9) Hz. These studies demonstrate that weakly bound organic molecules can be confined on a surface by creating molecular barriers, potentially altering their assembly.
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Affiliation(s)
- Stephen C Jensen
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
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37
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Wilson DP, Sporleder D, White MG. Final state distributions of methyl radical desorption from ketone photooxidation on TiO2(110). Phys Chem Chem Phys 2012; 14:13630-7. [DOI: 10.1039/c2cp42628e] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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38
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Shen M, Henderson MA. Site competition during coadsorption of acetone with methanol and water on TiO2(110). LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:9430-9438. [PMID: 21692462 DOI: 10.1021/la2016726] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The competitive interaction between acetone and two solvent molecules (methanol and water) for surface sites on rutile TiO(2)(110) was studied using temperature-programmed desorption (TPD). On a vacuum-annealed TiO(2)(110) surface, which possessed ~5% oxygen vacancy sites, excess methanol displaced preadsorbed acetone molecules to weakly bound and physisorbed desorption states below 200 K. In contrast, acetone molecules were stabilized on an oxidized surface against displacement by methanol through formation of acetone diolate species. The behavior of acetone with methanol differs from the interactions between acetone and water which are less competitive. Examination of acetone + methanol and acetone + water multilayer combinations shows that acetone is more compatible in water-ice films than in methanol-ice films, presumably because water has greater potential as a hydrogen-bond donor than does methanol. Acetone molecules displaced from the TiO(2)(110) surface by water are more likely to be retained in the near-surface region, in turn having a greater opportunity to revisit the surface, than when methanol is used as a coadsorbate.
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Affiliation(s)
- Mingmin Shen
- Chemical and Materials Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, MS K8-87, Richland, Washington 99352, USA
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39
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Henderson M, Deskins N, Zehr R, Dupuis M. Generation of organic radicals during photocatalytic reactions on TiO2. J Catal 2011. [DOI: 10.1016/j.jcat.2011.01.021] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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40
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The Role of Surface and Subsurface Point Defects for Chemical Model Studies on TiO
2
: A First‐Principles Theoretical Study of Formaldehyde Bonding on Rutile TiO
2
(110). Chemistry 2011; 17:4496-506. [DOI: 10.1002/chem.201002588] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2010] [Indexed: 11/07/2022]
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41
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Benz L, Haubrich J, Jensen SC, Friend CM. Molecular imaging of reductive coupling reactions: interstitial-mediated coupling of benzaldehyde on reduced TiO2(110). ACS NANO 2011; 5:834-843. [PMID: 21229961 DOI: 10.1021/nn103144u] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We report the first visualization of a reactive intermediate formed from coupling two molecules on a surface-a diolate formed from benzaldehyde coupling on TiO(2)(110). The diolate, imaged using scanning tunneling microscopy (STM), is reduced to gaseous stilbene upon heating to ∼400 K, leaving behind two oxygen atoms that react with reduced Ti interstitials that migrate to the surface, contrary to the popular expectation that strong bonds in oxygenated molecules react only with oxygen vacancies at the surface. Our work further provides both experimental and theoretical evidence that Ti interstitials drive the formation of diolate intermediates. Initially mobile monomers migrate together to form paired features, identified as diolates that bond over two adjacent five-coordiante Ti atoms on the surface. Our work is of broad importance because it demonstrates the possibility of imaging the distribution and bonding configurations of reactant species on a molecular scale, which is a critical part of understanding surface reactions and the development of surface morphology during the course of reaction.
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Affiliation(s)
- Lauren Benz
- Department of Chemistry and Biochemistry, University of San Diego, San Diego, California 92110, USA
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42
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Wen B, Li Y, Chen C, Ma W, Zhao J. An Unexplored O
2
‐Involved Pathway for the Decarboxylation of Saturated Carboxylic Acids by TiO
2
Photocatalysis: An Isotopic Probe Study. Chemistry 2010; 16:11859-66. [DOI: 10.1002/chem.201001704] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Bo Wen
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China), Fax: (+86) 108‐261‐6495
| | - Yue Li
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China), Fax: (+86) 108‐261‐6495
| | - Chuncheng Chen
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China), Fax: (+86) 108‐261‐6495
| | - Wanhong Ma
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China), Fax: (+86) 108‐261‐6495
| | - Jincai Zhao
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China), Fax: (+86) 108‐261‐6495
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43
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Benz L, Haubrich J, Quiller RG, Jensen SC, Friend CM. McMurry Chemistry on TiO2(110): Reductive C═C Coupling of Benzaldehyde Driven by Titanium Interstitials. J Am Chem Soc 2009; 131:15026-31. [DOI: 10.1021/ja905522c] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Lauren Benz
- Department of Chemistry and Chemical Biology and School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138
| | - Jan Haubrich
- Department of Chemistry and Chemical Biology and School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138
| | - Ryan G. Quiller
- Department of Chemistry and Chemical Biology and School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138
| | - Stephen C. Jensen
- Department of Chemistry and Chemical Biology and School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138
| | - Cynthia M. Friend
- Department of Chemistry and Chemical Biology and School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138
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44
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King R, Idriss H. Acetone reactions over the surfaces of polycrystalline UO2: a kinetic and spectroscopic study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:4543-4555. [PMID: 19366223 DOI: 10.1021/la803933t] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The reaction of acetone is studied on the surfaces of polycrystalline UO2, prepared by hydrogen reduction of U3O8 at 770 K. The study is conducted by in situ Fourier transform infrared (FTIR) and temperature-programmed desorption (TPD). Acetone adsorption does not fit the simple Langmuir model, and adsorbate-adsorbate interactions are found to be significant. Acetone adsorbs molecularly on UO2 as evidenced by the nuCO of the eta1(O) mode at 1686 cm(-1). Part of acetone is reduced to the isopropoxide species ((CH3)2HC-O-U4+) upon heating (nu(CC), rho(CH3) at 1167 cm(-1) and nu(CO), rho(CH3) at 980 cm(-1)), and upon further heating, acetates (CH3COO(a), (a) for adsorbed) are observed. Detailed TPD studies indicated that the main reaction of acetone on UO2 is the deoxygenation to propene, driven by the oxophilic nature of UO2. Other reactions were also observed to a lesser extent, and these included reductive coupling to 2,3-dimethylbutene and condensation to mesityl oxide. An attempt to extract kinetic parameters from TPD data was conducted. Three models were studied: variation of heating rate, leading edge analysis (Habenschaden-Kuppers method), and complete analysis. The complete analysis provided the most plausible results, in particular, at low coverage. With this method, at nearly zero coverage the activation energy, Ed, for desorption was found to be close to 140 kJ/mol with a prefactor of 10(13) s(-1). Ed dropped sharply with increasing coverage, theta, to ca. 35 kJ/mol at theta=0.15 with a prefactor of 10(11) s(-1). The activation energy for the desorption of acetone on UO2(111) single crystals, at saturation coverage, was previously found to be equal to 65 kJ/mol using the leading edge analysis.
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Affiliation(s)
- Richard King
- Department of Chemistry, The University of Auckland, Auckland, New Zealand
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45
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Du Y, Deskins NA, Zhang Z, Dohnálek Z, Dupuis M, Lyubinetsky I. Two pathways for water interaction with oxygen adatoms on TiO2(110). PHYSICAL REVIEW LETTERS 2009; 102:096102. [PMID: 19392536 DOI: 10.1103/physrevlett.102.096102] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2008] [Indexed: 05/27/2023]
Abstract
Scanning tunneling microscopy and density functional theory studies show that oxygen adatoms (Oa), produced during O2 exposure of reduced TiO2(110) surfaces, alter the water dissociation and recombination chemistry through two distinctive pathways. Depending on whether H2O and Oa are on the same or adjacent Ti4+ rows, Oa facilitates H2O dissociation and proton transfer to form a terminal hydroxyl pair, positioned along or across the Ti4+ row, respectively. The latter process has not been reported previously, and it starts from a "pseudodissociated" state of water. In both pathways, the reverse H transfer results in H2O reformation and O scrambling, as manifested by an apparent along- or across-row motion of Oa's.
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Affiliation(s)
- Y Du
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352, USA
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46
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Green J, Carter E, Murphy DM. An EPR investigation of acetonitrile reactivity with superoxide radicals on polycrystalline TiO2. RESEARCH ON CHEMICAL INTERMEDIATES 2009. [DOI: 10.1007/s11164-008-0022-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
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47
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Schmidt CM, Buchbinder AM, Weitz E, Geiger FM. Photochemistry of the Indoor Air Pollutant Acetone on Degussa P25 TiO2Studied by Chemical Ionization Mass Spectrometry. J Phys Chem A 2007; 111:13023-31. [DOI: 10.1021/jp076745+] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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48
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Hou H, Li Y, Wang B. Computational study of the reaction of atomic oxygen with acetone in the gas phase. J Phys Chem A 2006; 110:13163-71. [PMID: 17149829 DOI: 10.1021/jp065346w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Mechanisms and kinetics of the reaction of atomic oxygen with acetone have been investigated using ab initio quantum chemistry methods and transition state theory. The structures of the stationary points along the possible reaction pathways were obtained using the second-order Møller-Plesset theory and the coupled-cluster theory with single and double excitations with the triple-zeta quality basis sets. The energetics of the reaction pathways were calculated at the reduced second-order Gaussian-3 level and the extrapolated full coupled-cluster/complete basis set limit. The rate coefficients were calculated in the temperature range 200-3000 K, with the detailed consideration of the hindered internal rotation and the tunneling effect using Eckart and the semiclassical WKB approximations. It is shown that the predominant mechanism is the direct hydrogen abstraction producing hydroxyl and acetonyl radicals. Although the nucleophilic OC addition/elimination channel leading to CH3 and CO2 involves comparable barrier with the direct hydrogen abstraction channel, kinetically it cannot play any role in the overall reaction. It is predicted that the rate coefficients show positive temperature dependence in the range 200-3000 K and strong non-Arrhenius behavior. The tunneling effect plays a significant role. Moreover, the reaction has strong kinetic isotope effect. The calculated results are in good agreement with the available experimental data. The present rigorous theoretical work is helpful for the understanding of the characteristics of the reaction of atomic oxygen with acetone.
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Affiliation(s)
- Hua Hou
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, People's Republic of China
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49
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Schmidt CM, Weitz E, Geiger FM. Interaction of the indoor air pollutant acetone with Degussa P25 TiO2 studied by chemical ionization mass spectrometry. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2006; 22:9642-50. [PMID: 17073491 DOI: 10.1021/la061974t] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Preventing a build-up of indoor pollutant concentrations has emerged as a major goal in environmental chemistry. Here, we have applied chemical ionization mass spectrometry to study the interaction of acetone, a common indoor air pollutant, with Degussa P25 TiO2, an inexpensive catalyst that is widely used for the degradation of volatile organic compounds into CO2 and water. To better understand the adsorption of acetone onto Degussa P25, the necessary first step for its degradation, the experiments were carried out at room temperature in the absence of UV light. This allowed for the deconvolution of the nonreactive and reactive thermal binding processes on Degussa P25 at acetone partial pressures (10(-7)-10(-4) Torr) commonly found in indoor environments. On average, 30% of the adsorbed acetone is bound irreversibly, resulting in a surface coverage of irreversibly bound acetone of approximately 1 x 10(12) molecules/cm2 at 3-4 x 10(-5) Torr. Equilibrium and dynamic experiments yield a sticking coefficient of approximately 1 x 10(-4) that is independent of the acetone partial pressures examined here. Equilibrium binding constants and free energies of adsorption are reported.
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Affiliation(s)
- Catherine M Schmidt
- Department of Chemistry and the Institute for Environmental Catalysis, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, USA
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50
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Mattsson A, Leideborg M, Larsson K, Westin G, Osterlund L. Adsorption and Solar Light Decomposition of Acetone on Anatase TiO2 and Niobium Doped TiO2 Thin Films. J Phys Chem B 2005; 110:1210-20. [PMID: 16471666 DOI: 10.1021/jp055656z] [Citation(s) in RCA: 134] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Adsorption and solar light decomposition of acetone was studied on nanostructured anatase TiO2 and Nb-doped TiO2 films made by sol-gel methods (10 and 20 mol % NbO2.5). A detailed characterization of the film materials show that films contain only nanoparticles with the anatase modification with pentavalent Nb oxide dissolved into the anatase structure, which is interpreted as formation of substituted Nb=O clusters in the anatase lattice. The Nb-doped films displayed a slight yellow color and an enhanced the visible light absorption with a red-shift of the optical absorption edge from 394 nm for the pure TiO2 film to 411 nm for 20 mol % NbO2.5. In-situ Fourier transform infrared (FTIR) transmission spectroscopy shows that acetone adsorbs associatively with eta1-coordination to the surface cations on all films. On Nb-doped TiO2 films, the carbonyl bonding to the surface is stabilized, which is evidenced by a lowering of the nu(C=O) frequency by about 20 cm(-1) to 1672 cm(-1). Upon solar light illumination acetone is readily decomposed on TiO2, and stable surface coordinated intermediates are formed. The decomposition rate is an order of magnitude smaller on the Nb-doped films despite an enhanced visible light absorption in these materials. The quantum yield is determined to be 0.053, 0.004 and 0.002 for the pure, 10% Nb:TiO2, and 20%Nb:TiO2, respectively. Using an interplay between FTIR and DFT calculations we show that the key surface intermediates are bidentate bridged formate and carbonate, and H-bonded bicarbonate, respectively, whose concentration on the surface can be correlated with their heats of formation and bond strength to coordinatively unsaturated surface Ti and Nb atoms at the surface. The oxidation rate of these intermediates is substantially slower than the initial acetone decomposition rate, and limits the total oxidation rate at t>7 min on TiO2, while no decrease of the rate is observed on the Nb-doped films. The rate of degradation of key surface intermediates is different on pure TiO2 and Nb-doped TiO2, but cannot explain the overall lower total oxidation rate for the Nb-doped films. Instead the inferior photocatalytic activity in Nb-doped TiO2 is attributed to an enhanced electron-hole pair recombination rate due to Nb=O cluster and cation vacancy formation.
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Affiliation(s)
- Andreas Mattsson
- Department of Environment and Protection, FOI NBC Defence, SE-901 82 Umeå, Sweden
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