Geometric Occupancy and Oxidation State Requirements of Cations in

Mar 14, 2019 - Cobalt oxides, including spinel Co3O4 and rock-salt CoO, have been widely reported as promising catalysts for oxygen reduction reaction...
0 downloads 0 Views 900KB Size
Subscriber access provided by Stockholm University Library

Energy, Environmental, and Catalysis Applications

Geometric Occupancy and Oxidation State Requirements of Cations in Cobalt Oxides for Oxygen Reduction Reaction Jing Liu, Hongliang Bao, Bingsen Zhang, Qingfeng Hua, Mingfeng Shang, Jianqiang Wang, and Luhua Jiang ACS Appl. Mater. Interfaces, Just Accepted Manuscript • DOI: 10.1021/acsami.9b00481 • Publication Date (Web): 14 Mar 2019 Downloaded from http://pubs.acs.org on March 18, 2019

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 34 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Applied Materials & Interfaces

Geometric Occupancy and Oxidation State Requirements of Cations in Cobalt Oxides for Oxygen Reduction Reaction Jing Liu,†,+ Hongliang Bao,§,+ Bingsen Zhang,‡ Qingfeng Hua,† Mingfeng Shang,§ Jianqiang Wang,*,§ Luhua Jiang*,† †Nanomaterial

& Electrocatalysis Laboratory, College of Materials Science and Engineering,

Qingdao University of Science and Technology, 53 Zhengzhou Road, 266042, Qingdao, China. §Shanghai

Institute of Applied Physics, Chinese Academy of Science, 239 Zhangheng Road,

201204, Shanghai, China ‡Institute

of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, 110016,

Shenyang, China

ABSTRACT : Cobalt oxides, including spinel Co3O4 and rock-salt CoO, have been widely reported as promising catalysts for oxygen reduction reaction (ORR). However, three types of cobalt ions, i.e., Co2+ in the tetrahedral site (Co2+Td), Co3+ in the octahedral site (Co3+Oh) and Co2+ in the octahedral site (Co2+Oh), are included in these oxides, and the roles of cobalt geometric occupancy and valance states have remained elusive. Here, for the first time, we investigated the effects of cobalt geometric occupancy on the ORR activity by substituting Co2+Td and Co3+Oh of Co3O4 with inactive Zn2+ and Al3+, respectively. The ORR activity decreases in the order of Co3O4 (Co3+Oh, Co2+Th) < ZnCo2O4 (Co3+Oh)