Mastering Surface Reconstruction of Metastable Spinel Oxides for Better Water Oxidation. Issue 12 (24th January 2019)

• Record Type: Journal Article
• Authors: Duan, Yan; Sun, Shengnan; Sun, Yuanmiao; Xi, Shibo; Chi, Xiao; Zhang, Qinghua; Ren, Xiao; Wang, Jingxian; Ong, Samuel Jun Hoong; Du, Yonghua; Gu, Lin; Grimaud, Alexis; Xu, Zhichuan J.
• Is Part Of: Advanced materials. Volume 31:Issue 12(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-01-24
• Subjects: lattice oxygen evolution -- M d‐band center and O p‐band center -- oxygen evolution reaction -- spinel oxides -- surface reconstruction; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.201807898
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract: Developing highly active electrocatalysts for oxygen evolution reaction (OER) is critical for the effectiveness of water splitting. Low‐cost spinel oxides have attracted increasing interest as alternatives to noble metal–based OER catalysts. A rational design of spinel catalysts can be guided by studying the structural/elemental properties that determine the reaction mechanism and activity. Here, using density functional theory (DFT) calculations, it is found that the relative position of O p‐band and MOh (Co and Ni in octahedron) d‐band center in ZnCo2− x Ni x O4 ( x = 0–2) correlates with its stability as well as the possibility for lattice oxygen to participate in OER. Therefore, it is testified by synthesizing ZnCo2− x Ni x O4 spinel oxides, investigating their OER performance and surface evolution. Stable ZnCo2− x Ni x O4 ( x = 0–0.4) follows adsorbate evolving mechanism under OER conditions. Lattice oxygen participates in the OER of metastable ZnCo2− x Ni x O4 ( x = 0.6, 0.8) which gives rise to continuously formed oxyhydroxide as surface‐active species and consequently enhances activity. ZnCo1.2 Ni0.8 O4 exhibits performance superior to the benchmarked IrO2 . This work illuminates the design of highly active metastable spinel electrocatalysts through the prediction of the reaction mechanism and OER activity by determining the relative positions of the O p‐band and the MOh d‐band center. Abstract : Metastable spinel oxides for efficient water oxidation can be designed by a graduate substitution strategy. A systematic study on Ni‐substituted spinel ZnCo2 O4 indicates the relative position of M 3d and O 2p as an indicator of lattice oxygen stability. With Ni substitution, the surface reconstruction is activated toward a spinel with lattice oxygen mechanism for water oxidation.