Accelerating Fe sites saturation coverage through Bi-metal dynamic balances on double-layer hollow MOF nanocages for oxygen evolution. (October 2022)

• Record Type: Journal Article
• Authors: Xie, Jing-Yi; Zhang, Xin-Yu; Yu, Ning; Luan, Ren-Ni; Zhang, Dong-Zhi; Zeng, Jing-Bin; Chai, Yong-Ming; Dong, Bin
• Is Part Of: Materials today physics. Volume 27(2022)
• Publication Date: 2022-10
• Subjects: Double-layer hollow nanocages -- CoFe-PBA -- Dynamic interface -- Alkali etching -- Oxygen evolution reaction; Materials science -- Periodicals; Physics -- Periodicals; Electronic journals; 530.41
• DOI: 10.1016/j.mtphys.2022.100778
• Languages: English
• ISSNs: 2542-5293

Abstract

Abstract: In situ dynamic redeposition of Fe sites with high catalytic activity is crucial for enhancing performance of transition metal (TM) catalysts. However, saturated coverage of iron sites on substrate and dynamic deposition control are rarely reported. Herein, bi-metal dynamic balances are analyzed in depth based on interface of double-layer hollow metal-organic framework (MOF). The newly designed catalyst undergoes an accelerated deposition and saturation coverage of Fe ions via controlling the concentration of Fe(III) in electrolyte, as well as electron holes and active host. Importantly, the balance of iron dissolution and redeposition (main cycle) and the oxidation-reduction equilibrium of cobalt ions (by-cycle) are proposed, and also mechanism of their synergistic effect to improve the efficiency of OER is revealed. Furthermore, the formation mechanism of double-layer hollow cage is studied by time-dependent evolution process. This study may inspire a better catalyst system for OER in alkaline medium and further design on complex structured MOFs. Graphical abstract: This work proposed two bi-metal dynamic balances on the interface of double-layer hollow nanocage, and analyzed saturated coverage of iron active sites on substrate and dynamic deposition control. Furthermore, formation mechanism and advantage of this unique structure are studied by time-dependent evolution process. Image 1 Highlights: Accelerated saturated coverage of iron active sites on bi-metal MOFs is achieved. Fe(III) in electrolyte and Co in MOF contribute to the catalytic interface. The promoted mechanisms of bi-metal dynamic balances are analyzed. The host role of Co is the base for saturation coverage of Fe ions.