title: Modest Oxygen-Defective Amorphous Manganese-Based Nanoparticle Mullite with Superior Overall Electrocatalytic Performance for Oxygen Reduction Reaction.
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 SmMn2O5-δnanoparticles 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.
authors.affiliation: 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.
authors.forename: Chao
authors.initials: C
authors.lastname: Dong
authors.affiliation: 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.
authors.forename: Zi-Wei
authors.initials: ZW
authors.lastname: Liu
authors.affiliation: College of Electronic Information and Optical Engineering, Nankai University, Tianjin, 300071, China.
authors.forename: Jie-Yu
authors.initials: JY
authors.lastname: Liu
authors.affiliation: College of Electronic Information and Optical Engineering, Nankai University, Tianjin, 300071, China.
authors.forename: Wei-Chao
authors.initials: WC
authors.lastname: Wang
authors.affiliation: 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.
authors.forename: Lan
authors.initials: L
authors.lastname: Cui
authors.affiliation: Frontier Research Center for Materials Structure, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China.
authors.forename: Rui-Chun
authors.initials: RC
authors.lastname: Luo
authors.affiliation: Institute of Advance Polymer Materials, School of Materials Science and Engineering, Tianjin University, Tianjin, 300072, China.
authors.forename: Hui-Long
authors.initials: HL
authors.lastname: Guo
authors.affiliation: 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.
authors.forename: Xue-Li
authors.initials: XL
authors.lastname: Zheng
authors.affiliation: 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.
authors.forename: Shi-Zhang
authors.initials: SZ
authors.lastname: Qiao
authors.affiliation: 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.
authors.forename: Xi-Wen
authors.initials: XW
authors.lastname: Du
authors.affiliation: 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.
authors.forename: Jing
authors.initials: J
authors.lastname: Yang
keywords: amorphous; mullites; oxygen reduction reactions; oxygen vacancies; specific activities