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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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Plesco I, Ciobanu V, Braniste T, Ursaki V, Rasch F, Sarua A, Raevschi S, Adelung R, Dutta J, Tiginyanu I. Highly Porous and Ultra-Lightweight Aero-Ga 2O 3: Enhancement of Photocatalytic Activity by Noble Metals. MATERIALS (BASEL, SWITZERLAND) 2021; 14:1985. [PMID: 33921020 PMCID: PMC8071440 DOI: 10.3390/ma14081985] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 04/07/2021] [Accepted: 04/12/2021] [Indexed: 01/09/2023]
Abstract
A new type of photocatalyst is proposed on the basis of aero-β-Ga2O3, which is a material constructed from a network of interconnected tetrapods with arms in the form of microtubes with nanometric walls. The aero-Ga2O3 material is obtained by annealing of aero-GaN fabricated by epitaxial growth on ZnO microtetrapods. The hybrid structures composed of aero-Ga2O3 functionalized with Au or Pt nanodots were tested for the photocatalytic degradation of methylene blue dye under UV or visible light illumination. The functionalization of aero-Ga2O3 with noble metals results in the enhancement of the photocatalytic performances of bare material, reaching the performances inherent to ZnO while gaining the advantage of the increased chemical stability. The mechanisms of enhancement of the photocatalytic properties by activating aero-Ga2O3 with noble metals are discussed to elucidate their potential for environmental applications.
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Affiliation(s)
- Irina Plesco
- National Center for Materials Study and Testing, Technical University of Moldova, Stefan cel Mare Av. 168, MD-2004 Chisinau, Moldova; (V.C.); (T.B.); (V.U.)
| | - Vladimir Ciobanu
- National Center for Materials Study and Testing, Technical University of Moldova, Stefan cel Mare Av. 168, MD-2004 Chisinau, Moldova; (V.C.); (T.B.); (V.U.)
| | - Tudor Braniste
- National Center for Materials Study and Testing, Technical University of Moldova, Stefan cel Mare Av. 168, MD-2004 Chisinau, Moldova; (V.C.); (T.B.); (V.U.)
| | - Veaceslav Ursaki
- National Center for Materials Study and Testing, Technical University of Moldova, Stefan cel Mare Av. 168, MD-2004 Chisinau, Moldova; (V.C.); (T.B.); (V.U.)
| | - Florian Rasch
- Functional Nanomaterials, Institute for Materials Science, Kiel University, Kaiser Str. 2, 24143 Kiel, Germany; (F.R.); (R.A.)
| | - Andrei Sarua
- H. H. Wills Physics Laboratory, School of Physics, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, UK;
| | - Simion Raevschi
- Department of Physics and Engineering, State University of Moldova, Alexei Mateevici Str. 60, MD-2009 Chisinau, Moldova;
| | - Rainer Adelung
- Functional Nanomaterials, Institute for Materials Science, Kiel University, Kaiser Str. 2, 24143 Kiel, Germany; (F.R.); (R.A.)
| | - Joydeep Dutta
- Functional Materials Group, Applied Physics Department, School of Engineering Sciences, KTH Royal Institute of Technology, Hannes Alfvéns väg 12, 11419 Stockholm, Sweden;
| | - Ion Tiginyanu
- National Center for Materials Study and Testing, Technical University of Moldova, Stefan cel Mare Av. 168, MD-2004 Chisinau, Moldova; (V.C.); (T.B.); (V.U.)
- Academy of Sciences of Moldova, Stefan cel Mare Av. 1, MD-2001 Chisinau, Moldova
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