Wang Xiao-Tong, Ouyang Ting, Wang Ling, Zhong Jia-Huan, Ma Tianyi, Liu Zhao-Qing
School of Chemistry and Chemical Engineering, Institute of Clean Energy and Materials, Guangzhou University, Guangzhou Higher Education Mega Center, Guangzhou, No. 230 Wai Huan Xi Road, 510006, P. R. China.
Discipline of Chemistry, University of Newcastle, Newcastle, NSW, 2308, Australia.
Angew Chem Int Ed Engl. 2019 Sep 16;58(38):13291-13296. doi: 10.1002/anie.201907595. Epub 2019 Aug 7.
Bimetallic cobalt-based spinel is sparking much interest, most notably for its excellent bifunctional performance. However, the effect of Fe doping in Co O spinel remains poorly understood, mainly because the surface state of a catalyst is difficult to characterize. Herein, a bifunctional oxygen electrode composed of spinel Co FeO /(Co Fe ) (Co Fe ) O nanoparticles grown on N-doped carbon nanotubes (NCNTs) is designed, which exhibits superior performance to state-of-the-art noble metal catalysts. Theoretical calculations and magnetic measurements reveal that the introduction of Fe ions into the Co O network causes delocalization of the Co 3d electrons and spin-state transition. Fe ions can effectively activate adjacent Co ions under the action of both spin and charge effect, resulting in the enhanced intrinsic oxygen catalytic activity of the hybrid spinel Co FeO . This work provides not only a promising bifunctional electrode for zinc-air batteries, but also offers a new insight to understand the Co-Fe spinel oxides for oxygen electrocatalysis.
双金属钴基尖晶石引发了广泛关注，尤其是因其出色的双功能性能。然而，铁掺杂对钴酸钴尖晶石的影响仍知之甚少，主要是因为催化剂的表面状态难以表征。在此，设计了一种由生长在氮掺杂碳纳米管（NCNTs）上的尖晶石CoFeO /(CoFe)(CoFe)O纳米颗粒组成的双功能氧电极，其性能优于目前最先进的贵金属催化剂。理论计算和磁性测量表明，将铁离子引入钴酸钴网络会导致钴3d电子的离域和自旋态转变。铁离子在自旋和电荷效应的共同作用下可有效激活相邻的钴离子，从而增强混合尖晶石CoFeO的本征氧催化活性。这项工作不仅为锌空气电池提供了一种有前景的双功能电极，也为理解用于氧电催化的钴铁尖晶石氧化物提供了新的见解。
