High Configuration Entropy Activated Lattice Oxygen for O2 Formation on Perovskite Electrocatalyst. (13th April 2022)

• Record Type: Journal Article
• Authors: Tang, Lina; Yang, Yanling; Guo, Hongquan; Wang, Yue; Wang, Mengjie; Liu, Zuoqing; Yang, Guangming; Fu, Xianzhu; Luo, Yang; Jiang, Chenxing; Zhao, Yingru; Shao, Zongping; Sun, Yifei
• Is Part Of: Advanced functional materials. Volume 32:Number 28(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-04-13
• Subjects: density functional theory -- high entropy -- lattice oxygen mechanism -- oxygen evolution -- perovskite oxide; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.202112157
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract: The single‐phase oxides with elemental complexity and compositional diversity, usually named high entropy oxides, feature homogeneously dispersed multi‐metallic elements in equiatomic concentration. The unusual properties of high entropy oxides endow their potential application in clean‐energy‐related electrocatalysis. However, the possible fundamental relationship between configuration entropy and the underlying catalytic mechanism is still not well understood and established. Herein, a high entropy perovskite cobaltate consisting of five equimolar metals in the B‐site (Mg, Mn, Fe, Co, and Ni) is employed as an electrocatalyst for oxygen evolution reaction (OER). The configuration entropy serves as an effective tool to promote the intrinsic activity of the Co reactive site and manipulate the OER mechanism. The high entropy cobaltate demonstrates a lower overpotential of 320 mV at a current density of 10 mA cm −2, outperforming other counterparts. The X‐ray spectroscopies disclose the synergistic charge‐exchange effect among different cations and the formation of a new oxygen hole state. Combinatorially computational and experimental results unveil the enigma that the high configuration entropy leads to the random occupation of cations, facilitates the surface reconstruction, and benefits the formation of stable surface oxygen vacancies. Owing to these merits, the O2 formation is found to be kinetically favorable via the lattice oxygen mechanism. Abstract : The configuration entropy is proposed as an effective solution to lower the usage of the expensive element, enhance the intrinsic reactivity, and tune the oxygen evolution reaction mechanism of the perovskite cobaltate electrocatalyst. The entropy effect is closely associated with the inter‐cation charge transfer, creation of oxygen hole states around E f, and formation of surface oxygen vacancies, granting the material faster reaction kinetics.