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Cheng T, Wu X, Qiu Y, Yuan B, Zhao C, Chen JL, Peng YK. Spatially Decoupled H 2O 2 Activation Pathways and Multi-Enzyme Activities in Rod-Shaped CeO 2 with Implications for Facet Distribution. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024:e2401032. [PMID: 38618652 DOI: 10.1002/smll.202401032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 03/23/2024] [Indexed: 04/16/2024]
Abstract
CeO2, particularly in the shape of rod, has recently gained considerable attention for its ability to mimic peroxidase (POD) and haloperoxidase (HPO). However, this multi-enzyme activities unavoidably compete for H2O2 affecting its performance in relevant applications. The lack of consensus on facet distribution in rod-shaped CeO2 further complicates the establishment of structure-activity correlations, presenting challenges for progress in the field. In this study, the HPO-like activity of rod-shaped CeO2 is successfully enhanced while maintaining its POD-like activity through a facile post-calcination method. By studying the spatial distribution of these two activities and their exclusive H2O2 activation pathways on CeO2 surfaces, this study finds that the increased HPO-like activity originated from the newly exposed (111) surface at the tip of the shortened rods after calcination, while the unchanged POD-like activity is attributed to the retained (110) surface in their lateral area. These findings not only address facet distribution discrepancies commonly reported in the literature for rod-shaped CeO2 but also offer a simple approach to enhance its antibacterial performance. This work is expected to provide atomic insights into catalytic correlations and guide the design of nanozymes with improved activity and reaction specificity.
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Affiliation(s)
- Tianqi Cheng
- Department of Chemistry, City University of Hong Kong, Hong Kong SAR, Hong Kong
| | - Xinyu Wu
- Department of Chemistry, City University of Hong Kong, Hong Kong SAR, Hong Kong
| | - Yuwei Qiu
- Department of Chemistry, City University of Hong Kong, Hong Kong SAR, Hong Kong
| | - Bo Yuan
- Department of Chemistry, City University of Hong Kong, Hong Kong SAR, Hong Kong
| | - Chao Zhao
- Department of Chemistry, City University of Hong Kong, Hong Kong SAR, Hong Kong
| | - Jian Lin Chen
- Department of Applied Science, School of Science and Technology, Hong Kong Metropolitan University, Hong Kong SAR, Hong Kong
| | - Yung-Kang Peng
- Department of Chemistry, City University of Hong Kong, Hong Kong SAR, Hong Kong
- City University of Hong Kong Chengdu Research Institute, Chengdu, China
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2
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Yuan B, Tan Z, Guo Q, Shen X, Zhao C, Chen JL, Peng YK. Regulating the H 2O 2 Activation Pathway on a Well-Defined CeO 2 Nanozyme Allows the Entire Steering of Its Specificity between Associated Enzymatic Reactions. ACS NANO 2023; 17:17383-17393. [PMID: 37578491 DOI: 10.1021/acsnano.3c05409] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
Nanozymes are promising alternatives to natural enzymes, but their use remains limited owing to poor specificity. For example, CeO2 activates H2O2 and displays peroxidase (POD)-like, catalase (CAT)-like, and haloperoxidase (HPO)-like activities. Since they unavoidably compete for H2O2, affecting its utilization in the target application, the precise manipulation of reaction specificity is thus imperative. Herein, we showed that one can simply achieve this by manipulating the H2O2 activation pathway on pristine CeO2 in well-defined shapes. This is because the coordination and electronic structures of Ce sites vary with CeO2 surfaces, wherein the (100) and (111) surfaces display nearly 100% specificity toward POD-/CAT-like and HPO-like activities, respectively. The antibacterial results suggest that the latter surface can well-utilize H2O2 to kill bacteria (cf., the former), which is promising for anti-biofouling applications. This work provides atomic insights into the synthesis of nanozymes with improved activity, reaction specificity, and H2O2 utilization.
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Affiliation(s)
- Bo Yuan
- Department of Chemistry, City University of Hong Kong, Hong Kong 999077, Hong Kong SAR
| | - Zicong Tan
- Department of Chemistry, City University of Hong Kong, Hong Kong 999077, Hong Kong SAR
| | - Qiang Guo
- Department of Applied Science, School of Science and Technology, Hong Kong Metropolitan University, Hong Kong, Hong Kong SAR
| | - Xiutong Shen
- Department of Chemistry, City University of Hong Kong, Hong Kong 999077, Hong Kong SAR
| | - Chao Zhao
- Department of Chemistry, City University of Hong Kong, Hong Kong 999077, Hong Kong SAR
| | - Jian Lin Chen
- Department of Applied Science, School of Science and Technology, Hong Kong Metropolitan University, Hong Kong, Hong Kong SAR
| | - Yung-Kang Peng
- Department of Chemistry, City University of Hong Kong, Hong Kong 999077, Hong Kong SAR
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3
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Pacchioni G, Rahman TS. Defect engineering of oxide surfaces: dream or reality? JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:291501. [PMID: 35504272 DOI: 10.1088/1361-648x/ac6c6d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 05/03/2022] [Indexed: 06/14/2023]
Abstract
In this brief perspective we analyze the present status of the field of defect engineering of oxide surfaces. In particular we discuss the tools and techniques available to generate, identify, quantify, and characterize point defects at oxide surfaces and the main areas where these centers play a role in practical applications.
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Affiliation(s)
- Gianfranco Pacchioni
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, via R. Cozzi 55, 202125, Milano, Italy
| | - Talat S Rahman
- Department of Physics, University of Central Florida, Orlando, FL 32816, United States of America
- Renewable Energy and Chemical Transformation Cluster, University of Central Florida, Orlando, FL 32816, United States of America
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Halawy SA, Osman AI, Abdelkader A, Nasr M, Rooney DW. Assessment of Lewis-Acidic Surface Sites Using Tetrahydrofuran as a Suitable and Smart Probe Molecule. Chemistry 2022; 11:e202200021. [PMID: 35324079 PMCID: PMC8944219 DOI: 10.1002/open.202200021] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 03/04/2022] [Indexed: 02/03/2023]
Abstract
Measuring the Lewis‐acidic surface sites in catalysis is problematic when the material‘s surface area is very low (SBET ≤1 m2 ⋅ g−1). For the first time, a quantitative assessment of total acidic surface sites of very small surface area catalysts (MoO3 as pure and mixed with 5–30 % CdO (wt/wt), as well as CdO for comparison) was performed using a smart new probe molecule, tetrahydrofuran (THF). The results were nearly identical compared to using another commonly used probe molecule, pyridine. This audition is based on the limited values of the surface area of these samples that likely require a relatively moderate basic molecule as THF with pKb=16.08, rather than strong basic molecules such as NH3 (pKb=4.75) or pyridine (pKb=8.77). We propose mechanisms for the interaction of vapour phase molecules of THF with the Lewis‐cationic Mo and Cd atoms of these catalysts. Besides, dehydration of isopropyl alcohol was used as a probe reaction to investigate the catalytic activity of these catalysts to further support our findings in the case of THF in a temperature range of 175–300 °C. A good agreement between the obtained data of sample MoO3‐10 % CdO, which is characterised by the highest surface area value, the population of Lewis‐acidic sites and % selectivity of propylene at all the applied reaction temperatures was found.
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Affiliation(s)
- Samih A Halawy
- Nanocomposite Catalysts Lab., Chemistry Department, Faculty of Science at Qena, South Valley University, Qena, 83523, Egypt
| | - Ahmed I Osman
- Nanocomposite Catalysts Lab., Chemistry Department, Faculty of Science at Qena, South Valley University, Qena, 83523, Egypt.,School of Chemistry and Chemical Engineering, Queen's University Belfast, David Keir Building, Belfast, BT9 5AG, UK
| | - Adel Abdelkader
- Nanocomposite Catalysts Lab., Chemistry Department, Faculty of Science at Qena, South Valley University, Qena, 83523, Egypt
| | - Mahmoud Nasr
- Nanocomposite Catalysts Lab., Chemistry Department, Faculty of Science at Qena, South Valley University, Qena, 83523, Egypt
| | - David W Rooney
- School of Chemistry and Chemical Engineering, Queen's University Belfast, David Keir Building, Belfast, BT9 5AG, UK
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Li Y, Tsang SCE. Unusual Catalytic Properties of High-Energetic-Facet Polar Metal Oxides. Acc Chem Res 2021; 54:366-378. [PMID: 33382242 DOI: 10.1021/acs.accounts.0c00641] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
ConspectusHeterogeneous catalysis is an area of great importance not only in chemical industries but also in energy conversion and environmental technologies. It is well-established that the specific surface morphology and structure of solid catalysts exert remarkable effects on catalytic performances, since most physical and chemical processes take place on the surface during catalytic reactions. Different from the widely studied faceted metallic nanoparticles, metal oxides give more complicated structures and surface features. Great progress has been achieved in controlling the shape and exposed facets of transition metal oxides during nanocrystal growth, usually by using surface-directing agents (SDAs). However, the effects of exposed facets remain controversial among researchers. It should be noted that high-energetic facets, especially polar facets, tend to lower their surface energy via different relaxation processes, such as surface reconstruction, redox change, adsorption of countercharged species, etc. These processes can subsequently lead to surface defect formation and break the surface stoichiometry, and the resulting changes in electronic configurations and charge migration properties all play important roles in heterogeneous catalysis. Because different materials prefer different relaxation methods, various surface features are created, and different techniques are required to investigate the different features from facet to facet. Conventional characterization techniques such as X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, etc. appear to be insufficient to elucidate the underlying principles of the facet effects. Consequently, an increasing number of novel techniques have been developed to differentiate the surface features, enabling greater understanding of the effects of facets on heterogeneous catalysis.In this Account, on the basis of previous studies by our own group, we will focus on the effects of tailored facets on heterogeneous catalysis introduced by engineered simple binary metal oxide nanomaterials primarily with exposed polar facets, in combination with detailed surface studies using a range of new characterization techniques. As a result, fundamental principles of the effects of facets are elucidated, and the structure-activity correlations are demonstrated. The surface features introduced by different relaxation processes are also investigated using a range of characterization techniques. For example, electron paramagnetic resonance spectroscopy is used to detect the oxygen vacancies, while probe-assisted solid-state NMR spectroscopy is shown to be facet-sensitive and able to evaluate the surface acidity. It is also shown that such different features influence the heterogeneous catalytic performances in different ways. With the help of first-principles density functional theory calculations, unique properties of the faceted metal oxides are discussed and unraveled. Besides, other materials such as transition metal chalcogenides and layered double hydroxides are also briefly discussed with regard to their application in facet-dependent catalysis studies.
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Affiliation(s)
- Yiyang Li
- Wolfson Catalysis Centre, Department of Chemistry, University of Oxford, Oxford OX1 3QR, U.K
| | - Shik Chi Edman Tsang
- Wolfson Catalysis Centre, Department of Chemistry, University of Oxford, Oxford OX1 3QR, U.K
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Tan Z, Chen YC, Zhang J, Chou JP, Hu A, Peng YK. Nanoisozymes: The Origin behind Pristine CeO 2 as Enzyme Mimetics. Chemistry 2020; 26:10598-10606. [PMID: 32496593 DOI: 10.1002/chem.202001597] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 06/02/2020] [Indexed: 12/16/2022]
Abstract
It is known that the interplay between molecules and active sites on the topmost surface of a solid catalyst determines its activity in heterogeneous catalysis. The electron density of the active site is believed to affect both adsorption and activation of reactant molecules at the surface. Unfortunately, commercial X-ray photoelectron spectroscopy, which is often adopted for such characterization, is not sensitive enough to analyze the topmost surface of a catalyst. Most researchers fail to acknowledge this point during their catalytic correlation, leading to different interpretations in the literature in recent decades. Recent studies on pristine Cu2 O [Nat. Catal. 2019, 2, 889; Nat. Energy 2019, 4, 957] have clearly suggested that the electron density of surface Cu is facet dependent and plays a key role in CO2 reduction. Herein, it is shown that pristine CeO2 can reach 2506/1133 % increase in phosphatase-/peroxidase-like activity if the exposed surface is wisely selected. By using NMR spectroscopy with a surface probe, the electron density of the surface Ce (i.e., the active site) is found to be facet dependent and the key factor dictating their enzyme-mimicking activities. Most importantly, the surface area of the CeO2 morphologies is demonstrated to become a factor only if surface Ce can activate the adsorbed reactant molecules.
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Affiliation(s)
- Zicong Tan
- Department of Chemistry, City University of Hong Kong, Hong Kong, S.A.R. China
| | - Yu-Cheng Chen
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong, S.A.R. China
| | - Jieru Zhang
- Department of Chemistry, City University of Hong Kong, Hong Kong, S.A.R. China
| | - Jyh-Pin Chou
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong, S.A.R. China
| | - Alice Hu
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong, S.A.R. China
| | - Yung-Kang Peng
- Department of Chemistry, City University of Hong Kong, Hong Kong, S.A.R. China.,City University of Hong Kong, Shenzhen Research Institute, Shenzhen, 518057, P.R. China
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Tan Z, Zhang J, Chen YC, Chou JP, Peng YK. Unravelling the Role of Structural Geometry and Chemical State of Well-Defined Oxygen Vacancies on Pristine CeO 2 for H 2O 2 Activation. J Phys Chem Lett 2020; 11:5390-5396. [PMID: 32545965 DOI: 10.1021/acs.jpclett.0c01557] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Although H2O2 has been often employed as a green oxidant for many CeO2-catalyzed reactions, the underlying principle of its activation by surface oxygen vacancy (Vo) is still elusive due to the irreversible removal of postgenerated Vo by water (or H2O2). The metastable Vo (ms-Vo) naturally preserved on pristine CeO2 surfaces was adopted herein for an in-depth study of their interplay with H2O2. Their well-defined local structures and chemical states were found facet-dependent affecting both the adsorption and subsequent activation of H2O2. It is concluded that a strong adsorption of H2O2 on ms-Vo may not guarantee its subsequent activation. The ms-Vo can be only free for the next catalytic cycle when the electron density of surface Ce is high enough to reduce/break the O-O bond of adsorbed H2O2. This explains the 211.8 and 35.8 times enhancement in H2O2 reactivity when the CeO2 surface is changed from (111) and (110) to (100).
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Affiliation(s)
- Zicong Tan
- Department of Chemistry, City University of Hong Kong, Hong Kong SAR, China
| | - Jieru Zhang
- Department of Chemistry, City University of Hong Kong, Hong Kong SAR, China
| | - Yu-Cheng Chen
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong SAR, China
| | - Jyh-Pin Chou
- Department of Physics, National Changhua University of Education, Changhua 500, Taiwan
| | - Yung-Kang Peng
- Department of Chemistry, City University of Hong Kong, Hong Kong SAR, China
- City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, China
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8
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Tan Z, Li G, Chou HL, Li Y, Yi X, Mahadi AH, Zheng A, Edman Tsang SC, Peng YK. Differentiating Surface Ce Species among CeO2 Facets by Solid-State NMR for Catalytic Correlation. ACS Catal 2020. [DOI: 10.1021/acscatal.0c00014] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Zicong Tan
- Department of Chemistry, City University of Hong Kong, Kowloon, Hong Kong 999077, P. R. China
| | - Guangchao Li
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Hung-Lung Chou
- Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei 10617, Taiwan
| | - Yiyang Li
- The Wolfson Catalysis Centre, Department of Chemistry, University of Oxford, Oxford OX1 3QR, U.K
| | - Xianfeng Yi
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, P. R. China
| | - Abdul Hanif Mahadi
- Centre for Advanced Material and Energy Sciences, Universiti Brunei Darussalam, Gadong 1410, Negara Brunei Darussalam
| | - Anmin Zheng
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, P. R. China
- School of Materials Science and Engineering, Zhengzhou University, Zhengzhou, Henan 450052, P. R. China
| | - Shik Chi Edman Tsang
- The Wolfson Catalysis Centre, Department of Chemistry, University of Oxford, Oxford OX1 3QR, U.K
| | - Yung-Kang Peng
- Department of Chemistry, City University of Hong Kong, Kowloon, Hong Kong 999077, P. R. China
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9
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Peng YK, Keeling B, Li Y, Zheng J, Chen T, Chou HL, Puchtler TJ, Taylor RA, Tsang SCE. Unravelling the key role of surface features behind facet-dependent photocatalysis of anatase TiO2. Chem Commun (Camb) 2019; 55:4415-4418. [DOI: 10.1039/c9cc01561b] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The high activity of the anatase TiO2(001) facet in photocatalytic H2 evolution is due to local electronic effects created by surface F on the facet.
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Affiliation(s)
- Yung-Kang Peng
- The Wolfson Catalysis Centre
- Department of Chemistry
- University of Oxford
- Oxford
- UK
| | - Benedict Keeling
- The Wolfson Catalysis Centre
- Department of Chemistry
- University of Oxford
- Oxford
- UK
| | - Yiyang Li
- The Wolfson Catalysis Centre
- Department of Chemistry
- University of Oxford
- Oxford
- UK
| | - Jianwei Zheng
- The Wolfson Catalysis Centre
- Department of Chemistry
- University of Oxford
- Oxford
- UK
| | - Tianyi Chen
- The Wolfson Catalysis Centre
- Department of Chemistry
- University of Oxford
- Oxford
- UK
| | - Hung-Lung Chou
- Graduate Institute of Applied Science and Technology
- National Taiwan University of Science and Technology
- Taipei 10617
- Taiwan
| | - Tim J. Puchtler
- Clarendon Laboratory
- Department of Physics
- University of Oxford
- Oxford
- UK
| | - Robert A. Taylor
- Clarendon Laboratory
- Department of Physics
- University of Oxford
- Oxford
- UK
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10
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Du JH, Peng L. Recent progress in investigations of surface structure and properties of solid oxide materials with nuclear magnetic resonance spectroscopy. CHINESE CHEM LETT 2018. [DOI: 10.1016/j.cclet.2018.02.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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11
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Peng YK, Chou HL, Edman Tsang SC. Differentiating surface titanium chemical states of anatase TiO 2 functionalized with various groups. Chem Sci 2018; 9:2493-2500. [PMID: 29732126 PMCID: PMC5909675 DOI: 10.1039/c7sc04828a] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 01/28/2018] [Indexed: 11/28/2022] Open
Abstract
The local electronic effects on surface Ti, caused by adsorbates on TiO2 facets, are probed experimentally (using probe-assisted NMR spectroscopy) and theoretically (using DFT).
As the chemical state of titanium on the surface of TiO2 can be tuned by varying its host facet and surface adsorbate, improved performance has been achieved in fields such as heterogeneous (photo)catalysis, lithium batteries, dye-sensitized solar cells, etc. However, at present, no acceptable surface technique can provide information about the chemical state and distribution of surface cations among facets, making it difficult to unambiguously correlate facet-dependent properties. Even though X-ray photoelectron spectroscopy (XPS) is regarded as a sensitive surface technique, it collects data from the top few layers of the sample, instead of a specific facet, and hence fails to distinguish small changes in the chemical state of Ti imposed by adsorbates on a facet. Herein, based on experimental (chemical probe-assisted NMR) and theoretical (DFT) studies, the true surface Ti chemical states associated with surface modification using –O–, –F, –OH and –SO4 functional groups on the (001) and (101) facets of anatase TiO2 are clearly distinguished. It is also demonstrated, for the first time, that the local electronic effects on surface Ti imposed by adsorbates vary depending on the facet, due to different intrinsic electronic structures.
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Affiliation(s)
- Yung-Kang Peng
- Department of Chemistry , University of Oxford , OX1 3QR , UK .
| | - Hung-Lung Chou
- Graduate Institute of Applied Science and Technology , National Taiwan University of Science and Technology , Taipei 10617 , Taiwan .
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12
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Zheng A, Liu SB, Deng F. 31P NMR Chemical Shifts of Phosphorus Probes as Reliable and Practical Acidity Scales for Solid and Liquid Catalysts. Chem Rev 2017; 117:12475-12531. [DOI: 10.1021/acs.chemrev.7b00289] [Citation(s) in RCA: 196] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Anmin Zheng
- State
Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics,
National Center for Magnetic Resonance in Wuhan, Key Laboratory of
Magnetic Resonance in Biological Systems, Wuhan Institute of Physics and Mathematics, the Chinese Academy of Sciences, Wuhan 430071, China
| | - Shang-Bin Liu
- Institute
of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
| | - Feng Deng
- State
Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics,
National Center for Magnetic Resonance in Wuhan, Key Laboratory of
Magnetic Resonance in Biological Systems, Wuhan Institute of Physics and Mathematics, the Chinese Academy of Sciences, Wuhan 430071, China
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13
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Peng YK, Hu Y, Chou HL, Fu Y, Teixeira IF, Zhang L, He H, Tsang SCE. Mapping surface-modified titania nanoparticles with implications for activity and facet control. Nat Commun 2017; 8:675. [PMID: 28939869 PMCID: PMC5610198 DOI: 10.1038/s41467-017-00619-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 07/13/2017] [Indexed: 12/03/2022] Open
Abstract
The use of surface-directing species and surface additives to alter nanoparticle morphology and physicochemical properties of particular exposed facets has recently been attracting significant attention. However, challenges in their chemical analysis, sometimes at trace levels, and understanding their roles to elucidate surface structure–activity relationships in optical (solar cells) or (photo)catalytic performance and their removal are significant issues that remain to be solved. Here, we show a detailed analysis of TiO2 facets promoted with surface species (OH, O, SO4, F) with and without post-treatments by 31P adsorbate nuclear magnetic resonance, supported by a range of other characterization tools. We demonstrate that quantitative evaluations of the electronic and structural effects imposed by these surface additives and their removal mechanisms can be obtained, which may lead to the rational control of active TiO2 (001) and (101) facets for a range of applications. Metal oxide nanocrystals can be grown with different facets exposed to give variations in reactivity, but the chemical state of these surfaces is not clear. Here, the authors make use of a phosphine probe molecule allowing the differences in surface chemistry to be mapped by NMR spectroscopy.
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Affiliation(s)
- Yung-Kang Peng
- The Wolfson Catalysis Centre, Department of Chemistry, University of Oxford, Oxford, OX1 3QR, UK
| | - Yichen Hu
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai, 200433, People's Republic of China
| | - Hung-Lung Chou
- Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei, 10617, Taiwan
| | - Yingyi Fu
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai, 200433, People's Republic of China
| | - Ivo F Teixeira
- The Wolfson Catalysis Centre, Department of Chemistry, University of Oxford, Oxford, OX1 3QR, UK
| | - Li Zhang
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai, 200433, People's Republic of China
| | - Heyong He
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai, 200433, People's Republic of China
| | - Shik Chi Edman Tsang
- The Wolfson Catalysis Centre, Department of Chemistry, University of Oxford, Oxford, OX1 3QR, UK.
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