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Hu H, Xu Z, Zhang Z, Yan X, Zhu Y, Attfield JP, Yang M. Electrocatalytic Oxygen Reduction Using Metastable Zirconium Suboxide. Angew Chem Int Ed Engl 2024; 63:e202404374. [PMID: 38726699 DOI: 10.1002/anie.202404374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2024] [Indexed: 06/19/2024]
Abstract
Strategies for discovery of high-performance electrocatalysts are important to advance clean energy technologies. Metastable phases such as low temperature or interfacial structures that are difficult to access in bulk may offer such catalytically active surfaces. We report here that the suboxide Zr3O, which is formed at Zr-ZrO2 interfaces but does not appear in the experimental Zr-O phase diagram exhibits outstanding oxygen reduction reaction (ORR) performance surpassing that of benchmark Pt/C and most transition metal-based catalysts. Addition of Fe3C nanoparticles to give a Zr-Zr3O-Fe3C/NC catalyst (NC=nitrogen-doped carbon) gives a half-wave potential (E1/2) of 0.914 V, outperforming Pt/C and showing only a 3 mV decrease after 20,000 electrochemical cycles. A zinc-air battery (ZAB) using this cathode material has a high power density of 241.1 mW cm-2 and remains stable for over 50 days of continuous cycling, demonstrating potential for practical applications. Zr3O demonstrates that interfacial or other phases that are difficult to stabilize may offer new directions for the discovery of high-performance electrocatalysts.
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Affiliation(s)
- Huashuai Hu
- School of Environmental Science and Technology, Dalian University of Technology, No.2 Linggong Road, Ganjingzi District, Dalian, 116024, China
| | - Zhihang Xu
- Department of Applied Physics, Research Institute for Smart Energy, The Hong Kong Polytechnic University Hung Hom, Kowloon, Hong Kong, 999077, China
| | - Zhaorui Zhang
- School of Environmental Science and Technology, Dalian University of Technology, No.2 Linggong Road, Ganjingzi District, Dalian, 116024, China
| | - Xiaohui Yan
- School of Environmental Science and Technology, Dalian University of Technology, No.2 Linggong Road, Ganjingzi District, Dalian, 116024, China
| | - Ye Zhu
- Department of Applied Physics, Research Institute for Smart Energy, The Hong Kong Polytechnic University Hung Hom, Kowloon, Hong Kong, 999077, China
| | - J Paul Attfield
- Centre for Science at Extreme Conditions and School of Chemistry, University of Edinburgh, King's Buildings, Mayfield Road, Edinburgh, EH9 3JZ, UK
| | - Minghui Yang
- School of Environmental Science and Technology, Dalian University of Technology, No.2 Linggong Road, Ganjingzi District, Dalian, 116024, China
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Ramachandran P, Khor BK, Lee CY, Doong RA, Oon CE, Thanh NTK, Lee HL. N-Doped Graphene Quantum Dots/Titanium Dioxide Nanocomposites: A Study of ROS-Forming Mechanisms, Cytotoxicity and Photodynamic Therapy. Biomedicines 2022; 10:biomedicines10020421. [PMID: 35203630 PMCID: PMC8962365 DOI: 10.3390/biomedicines10020421] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 01/07/2022] [Accepted: 01/09/2022] [Indexed: 12/12/2022] Open
Abstract
Titanium dioxide nanoparticles (TiO2 NPs) have been proven to be potential candidates in cancer therapy, particularly photodynamic therapy (PDT). However, the application of TiO2 NPs is limited due to the fast recombination rate of the electron (e−)/hole (h+) pairs attributed to their broader bandgap energy. Thus, surface modification has been explored to shift the absorption edge to a longer wavelength with lower e−/h+ recombination rates, thereby allowing penetration into deep-seated tumors. In this study, TiO2 NPs and N-doped graphene quantum dots (QDs)/titanium dioxide nanocomposites (N-GQDs/TiO2 NCs) were synthesized via microwave-assisted synthesis and the two-pot hydrothermal method, respectively. The synthesized anatase TiO2 NPs were self-doped TiO2 (Ti3+ ions), have a small crystallite size (12.2 nm) and low bandgap energy (2.93 eV). As for the N-GQDs/TiO2 NCs, the shift to a bandgap energy of 1.53 eV was prominent as the titanium (IV) tetraisopropoxide (TTIP) loading increased, while maintaining the anatase tetragonal crystal structure with a crystallite size of 11.2 nm. Besides, the cytotoxicity assay showed that the safe concentrations of the nanomaterials were from 0.01 to 0.5 mg mL−1. Upon the photo-activation of N-GQDs/TiO2 NCs with near-infrared (NIR) light, the nanocomposites generated reactive oxygen species (ROS), mainly singlet oxygen (1O2), which caused more significant cell death in MDA-MB-231 (an epithelial, human breast cancer cells) than in HS27 (human foreskin fibroblast). An increase in the N-GQDs/TiO2 NCs concentrations elevates ROS levels, which triggered mitochondria-associated apoptotic cell death in MDA-MB-231 cells. As such, titanium dioxide-based nanocomposite upon photoactivation has a good potential as a photosensitizer in PDT for breast cancer treatment.
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Affiliation(s)
- Pravena Ramachandran
- Nanomaterials Research Group, School of Chemical Sciences, Universiti Sains Malaysia (USM), Gelugor 11800, Penang, Malaysia;
| | - Boon-Keat Khor
- School of Pharmaceutical Sciences, Universiti Sains Malaysia (USM), Gelugor 11800, Penang, Malaysia; (B.-K.K.); (C.Y.L.)
| | - Chong Yew Lee
- School of Pharmaceutical Sciences, Universiti Sains Malaysia (USM), Gelugor 11800, Penang, Malaysia; (B.-K.K.); (C.Y.L.)
| | - Ruey-An Doong
- Institute of Analytical and Environmental Sciences, National Tsing Hua University, Hsinchu 30013, Taiwan;
| | - Chern Ein Oon
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia (USM), Gelugor 11800, Penang, Malaysia;
| | - Nguyen Thi Kim Thanh
- Biophysics Group, Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK
- UCL Healthcare Biomagnetics and Nanomaterials Laboratories, 21 Albemarle Street, London W1S 4BS, UK
- Correspondence: (N.T.K.T.); (H.L.L.)
| | - Hooi Ling Lee
- Nanomaterials Research Group, School of Chemical Sciences, Universiti Sains Malaysia (USM), Gelugor 11800, Penang, Malaysia;
- School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia
- Correspondence: (N.T.K.T.); (H.L.L.)
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Bao S, Liu H, Liang H, Li C, Bai J. Electrospinned silk-ribbon-like carbon-doped TiO2 ultrathin nanosheets for enhanced visible-light photocatalytic activity. Colloids Surf A Physicochem Eng Asp 2021. [DOI: 10.1016/j.colsurfa.2021.126289] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Tang L, Zhu M, Chen W, Tang S, Feng Y, Wang P, Liu X, Foo M, Wu M. Solid solution ZnW1−xMoxO4 for enhanced photocatalytic H2 evolution. NEW J CHEM 2020. [DOI: 10.1039/d0nj04622a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
ZnW1−xMoxO4 and n–n heterojunction ZnW1−xMoxO4/CdS complexes exhibited photocatalytic hydrogen evolution activity superior to that of pristine ZnWO4.
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Affiliation(s)
- Liang Tang
- School of Environmental and Chemical Engineering
- Shanghai University
- Shanghai 200444
- P. R. China
- Key Laboratory of Organic Compound Pollution Control Engineering
| | - Min Zhu
- School of Environmental and Chemical Engineering
- Shanghai University
- Shanghai 200444
- P. R. China
| | - Wenqian Chen
- School of Environmental and Chemical Engineering
- Shanghai University
- Shanghai 200444
- P. R. China
- Shanghai Institute of Applied Radiation
| | - Suwen Tang
- School of Environmental and Chemical Engineering
- Shanghai University
- Shanghai 200444
- P. R. China
| | - Yuan Feng
- School of Environmental and Chemical Engineering
- Shanghai University
- Shanghai 200444
- P. R. China
| | - Peng Wang
- School of Environmental and Chemical Engineering
- Shanghai University
- Shanghai 200444
- P. R. China
| | - Xiaonan Liu
- School of Environmental and Chemical Engineering
- Shanghai University
- Shanghai 200444
- P. R. China
| | - Mawlin Foo
- Department of Chemistry
- National University of Singapore
- Singapore
| | - Minghong Wu
- School of Environmental and Chemical Engineering
- Shanghai University
- Shanghai 200444
- P. R. China
- Key Laboratory of Organic Compound Pollution Control Engineering
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Facet-Dependent Interfacial Charge Transfer in TiO2/Nitrogen-Doped Graphene Quantum Dots Heterojunctions for Visible-Light Driven Photocatalysis. Catalysts 2019. [DOI: 10.3390/catal9040345] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Interfacial charge transfer is crucial in the efficient conversion of solar energy into fuels and electricity. In this paper, heterojunction composites were fabricated, comprised of anatase TiO2 with different percentages of exposed {101} and {001} facets and nitrogen-doped quantum dots (NGQDs) to enhance the transfer efficiency of photo-excited charge carriers. The photocatalytic performances of all samples were evaluated for RhB degradation under visible light irradiation, and the hybrid containing TiO2 with 56% {001} facets demonstrated the best photocatalytic activity. The excellent photoactivity of TiO2/NGQDs was owed to the synergistic effects of the following factors: (i) The unique chemical features of NGQDs endowed NGQDs with high electronic conductivities and provided its direct contact with the TiO2 surface via forming Ti–O–C chemical bonds. (ii) The co-exposed {101} and {001} facets were beneficial for the separation and transfer of charge carriers in anatase TiO2. (iii) The donor-acceptor interaction between NGQDs and electron-rich {101} facets of TiO2 could remarkably enhance the photocurrent, thus hindering the charge carriers recombination rate. Extensive characterization of their physiochemical properties further showed the synergistic effect of facet-manipulated electron-hole separation in TiO2 and donor-acceptor interaction in graphene quantum dots (GQDs)/TiO2 on photocatalytic activity.
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