Highly-conductive Cu-substituted brownmillerite with emergent 3-dimensional oxygen vacancy channels

Han，Wenqiao1; Hu，Songbai1,2; Li，Xiaowen1; Liu，Qi1; Ye，Mao3; Xu，Zedong4; Hu，Sixia5; Zhu，Yuanmin6; Chen，Lang1,5

2023

10.1039/d3tc00501a

Journal of Materials Chemistry C   Impact Factor & Quartile

2050-7526

2050-7534

Lowering the oxygen content in transition-metal oxides will inevitably result in the formation of oxygen vacancies or novel crystal structures. In this work, we used Cu to substitute for Co in brownmillerite SrCoO (BM-SCO) and found that this cation-substitution strategy could effectively reduce the oxygen level. An emergent 3-dimensional channel was formed from the parent 2-dimensional ordered BM-SCO as the Cu concentration reached 33%. The were ordered in both in-plane (IP) and out-of-plane (OOP) directions and were stabilized by forming CoO pyramids in addition to the existing CoO octahedra and CoO tetrahedra. Further doping with Cu would convert more and more CoO octahedra to CoO pyramids. Although the oxygen content was lowered, the electric conductivity improved by 2-3 orders of magnitude by forming an intermediate conduction band, which makes Cu-substituted BM-SCO more conductive than perovskite SCO at room temperature. Cu-substituted SCO exhibited greatly improved OER performances and boosted electrochemical activity, which is much better than that of a number of Co-based catalysts and comparable to IrO a noble metal oxide. Our work shows that Cu-substitution in brownmillerites is an effective route to stabilize high oxygen vacancy concentration with highly-improved conductivity. The emergent 3-dimensional oxygen vacancy channels offer a promising option to improve the catalytic performances of Co-based complex oxides.

SCI

English

First ; Corresponding

NSFC (National Natural Science Foundation of China)["51972160","12004156"] ; Ministry of Science and Technology of the People's Republic of China[2022YFA1402903] ; Science and Technology Research Items of Shenzhen grant["JCYJ20190809142603695","JCYJ20190809181601639"] ; Basic and Applied Basic Research Foundation of Guangdong Province[2022A1515140092]

Materials Science ; Physics

Materials Science, Multidisciplinary ; Physics, Applied

WOS:000960960600001

ROYAL SOC CHEMISTRY

2-s2.0-85152111923

Scopus

1.Department of Physics,Southern University of Science and Technology,Shenzhen,518055,China
2.School of Physical Sciences,Great Bay University,Dongguan,523429,China
3.School of Physics and Materials Science,Guangzhou University,Guangzhou,510006,China
4.School of Electronics and Information Engineering,Tiangong University,Tianjin,300387,China
5.Core Research Facilities,Southern University of Science and Technology,Shenzhen,518055,China
6.School of Materials Science and Engineering,Dongguan University of Technology,Dongguan,523808,China

Han，Wenqiao,Hu，Songbai,Li，Xiaowen,et al. Highly-conductive Cu-substituted brownmillerite with emergent 3-dimensional oxygen vacancy channels[J]. Journal of Materials Chemistry C,2023,11(15).

Han，Wenqiao.,Hu，Songbai.,Li，Xiaowen.,Liu，Qi.,Ye，Mao.,...&Chen，Lang.(2023).Highly-conductive Cu-substituted brownmillerite with emergent 3-dimensional oxygen vacancy channels.Journal of Materials Chemistry C,11(15).

Han，Wenqiao,et al."Highly-conductive Cu-substituted brownmillerite with emergent 3-dimensional oxygen vacancy channels".Journal of Materials Chemistry C 11.15(2023).