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Dong C, Liu ZW, Liu JY, Wang WC, Cui L, Luo RC, Guo HL, Zheng XL, Qiao SZ, Du XW, Yang J. Modest Oxygen-Defective Amorphous Manganese-Based Nanoparticle Mullite with Superior Overall Electrocatalytic Performance for Oxygen Reduction Reaction. Small 2017; 13:1603903. [PMID: 28195444 DOI: 10.1002/smll.201603903] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 01/09/2017] [Indexed: 06/06/2023]
Abstract
Manganese-based oxides have exhibited high promise as noncoinage alternatives to Pt/C for catalyzing oxygen reduction reaction (ORR) in basic solution and a mix of Mn3+/4+ valence is believed to be vital in achieving optimum ORR performance. Here, it is proposed that, distinct from the most studied perovskites and spinels, Mn-based mullites with equivalent molar ratio of Mn3+ and Mn4+ provide a unique platform to maximize the role of Mn valence in facile ORR kinetics by introducing modest content of oxygen deficiency, which is also beneficial to enhanced catalytic activity. Accordingly, amorphous mullite SmMn2 O5-δ nanoparticles with finely tuned concentration of oxygen vacancies are synthesized via a versatile top-down approach and the modest oxygen-defective sample with an Mn3+ /Mn4+ ratio of 1.78, i.e., Mn valence of 3.36 gives rise to a superior overall ORR activity among the highest reported for the family of Mn-based oxides, comparable to that of Pt/C. Altogether, this study opens up great opportunities for mullite-based catalysts to be a cost-effective alternative to Pt/C in diverse electrochemical energy storage and conversion systems.
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Affiliation(s)
- Chao Dong
- Institute of New-Energy Materials, Key Laboratory of Advanced Ceramics and Machining Technology of Ministry of Education, School of Materials Science and Engineering, Tianjin University, Tianjin, 300072, China
| | - Zi-Wei Liu
- Institute of New-Energy Materials, Key Laboratory of Advanced Ceramics and Machining Technology of Ministry of Education, School of Materials Science and Engineering, Tianjin University, Tianjin, 300072, China
| | - Jie-Yu Liu
- College of Electronic Information and Optical Engineering, Nankai University, Tianjin, 300071, China
| | - Wei-Chao Wang
- College of Electronic Information and Optical Engineering, Nankai University, Tianjin, 300071, China
| | - Lan Cui
- Institute of New-Energy Materials, Key Laboratory of Advanced Ceramics and Machining Technology of Ministry of Education, School of Materials Science and Engineering, Tianjin University, Tianjin, 300072, China
| | - Rui-Chun Luo
- Frontier Research Center for Materials Structure, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Hui-Long Guo
- Institute of Advance Polymer Materials, School of Materials Science and Engineering, Tianjin University, Tianjin, 300072, China
| | - Xue-Li Zheng
- Institute of New-Energy Materials, Key Laboratory of Advanced Ceramics and Machining Technology of Ministry of Education, School of Materials Science and Engineering, Tianjin University, Tianjin, 300072, China
| | - Shi-Zhang Qiao
- Institute of New-Energy Materials, Key Laboratory of Advanced Ceramics and Machining Technology of Ministry of Education, School of Materials Science and Engineering, Tianjin University, Tianjin, 300072, China
- School of Chemical Engineering, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Xi-Wen Du
- Institute of New-Energy Materials, Key Laboratory of Advanced Ceramics and Machining Technology of Ministry of Education, School of Materials Science and Engineering, Tianjin University, Tianjin, 300072, China
| | - Jing Yang
- Institute of New-Energy Materials, Key Laboratory of Advanced Ceramics and Machining Technology of Ministry of Education, School of Materials Science and Engineering, Tianjin University, Tianjin, 300072, China
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Li C, Luo RC, Mao YQ, Du XW, Yang J. ZnSe hollow nanospheres in mechanically stable near-IR antireflection coatings for ZnSe substrates. Nanotechnology 2016; 27:365604. [PMID: 27482737 DOI: 10.1088/0957-4484/27/36/365604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Though possessing low absorption throughout a wide infrared (IR) spectral regime, owing to a high refractive index, zinc selenide substrates are generally covered by antireflection coatings (ARCs) for practical optical uses. However, achieving a high transmission of ZnSe substrates in the near-IR (NIR) region is still challenging. Herein, for the first time, colloidal ZnSe hollow nanospheres (HNSs) smaller than 100 nm were prepared and adopted to assemble ARCs for ZnSe substrates. The voiding kinetics of the HNSs was found to agree well with the nanoscale Kirkendall effect, and the self-diffusion of the Zn ion in the core was faster than its diffusion through the ZnSe shell. With single-index ARCs, the transmission of ZnSe substrates was remarkably enhanced in the NIR region, with up to an 18% increase at 840 nm. Besides, the ZnSe HNS-based ARCs showed superior mechanical stability even under violent ultrasonication in organic solutions. We expect that ZnSe HNSs will make it possible to construct graded-index ARCs to realize omnidirectional and broadband antireflection in IR, through further tuning of HNSs' void fraction.
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Affiliation(s)
- Chao Li
- Institute of New-Energy Materials, Tianjin Key Laboratory of Composite and Functional Materials, School of Materials Science and Engineering, Tianjin University, Tianjin 300072, People's Republic of China
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