title: Engineering electrocatalytic activity in nanosized perovskite cobaltite through surface spin-state transition.
abstract: The activity of electrocatalysts exhibits a strongly dependence on their electronic structures. Specifically, for perovskite oxides, Shao-Horn and co-workers have reported a correlation between the oxygen evolution reaction activity and the eg orbital occupation of transition-metal ions, which provides guidelines for the design of highly active catalysts. Here we demonstrate a facile method to engineer the eg filling of perovskite cobaltite LaCoO3 for improving the oxygen evolution reaction activity. By reducing the particle size to ∼80 nm, the eg filling of cobalt ions is successfully increased from unity to near the optimal configuration of 1.2 expected by Shao-Horn's principle. Consequently, the activity is significantly enhanced, comparable to those of recently reported cobalt oxides with eg(∼1.2) configurations. This enhancement is ascribed to the emergence of spin-state transition from low-spin to high-spin states for cobalt ions at the surface of the nanoparticles, leading to more active sites with increased reactivity.
authors.affiliation: Hefei National Laboratory for Physics Sciences at the Microscale, Hefei Science Center, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Shiming
authors.initials: S
authors.lastname: Zhou
authors.affiliation: Hefei National Laboratory for Physics Sciences at the Microscale, Hefei Science Center, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Xianbing
authors.initials: X
authors.lastname: Miao
authors.affiliation: Hefei National Laboratory for Physics Sciences at the Microscale, Hefei Science Center, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Xu
authors.initials: X
authors.lastname: Zhao
authors.affiliation: Hefei National Laboratory for Physics Sciences at the Microscale, Hefei Science Center, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Ma
authors.affiliation: School of Physics, Nankai University, Tianjin 300071, China.
authors.forename: Yuhao
authors.initials: Y
authors.lastname: Qiu
authors.affiliation: School of Physics, Nankai University, Tianjin 300071, China.|State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China.
authors.forename: Zhenpeng
authors.initials: Z
authors.lastname: Hu
authors.affiliation: Hefei National Laboratory for Physics Sciences at the Microscale, Hefei Science Center, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Jiyin
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Hefei National Laboratory for Physics Sciences at the Microscale, Hefei Science Center, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Shi
authors.affiliation: Hefei National Laboratory for Physics Sciences at the Microscale, Hefei Science Center, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Zeng