Defect Engineering, Electronic Structure, and Catalytic Properties of Perovskite Oxide La0.5Sr0.5CoO3−δ. Issue 5 (16th December 2016)

• Record Type: Journal Article
• Authors: Wang, Xiyang; Huang, Keke; Ma, Wei; Cong, Yingge; Ge, Chengda; Feng, Shouhua
• Is Part Of: Chemistry. Volume 23:Issue 5(2017)
• Page Start: 1093
• Page End: 1100
• Publication Date: 2016-12-16
• Subjects: catalytic properties -- cobalt -- electronic structure -- oxygen vacancies -- urea pyrolysis; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201604065
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: The electronic structures of transition metal oxides play a crucial role in the physical and chemical properties of solid materials. Defect engineering is an efficient way to regulate the electronic structure and improve the performance of materials. Here, we develop a defect engineering route that is implemented by controlling the topochemical reactions between cobalt perovskite and urea to optimize the electronic structure of La0.5 Sr0.5 CoO3− δ (LSCO). Urea pyrolysis is able to increase the oxygen defect concentration and cause octahedral distortions. Furthermore, we can distinctly observe that the introduction of oxygen vacancies narrows the hybridization orbital between O 2p and Co 3d and optimizes the O p‐band center near the Fermi level by X‐ray absorption spectroscopy, which greatly improves the catalytic activity of CO oxidation and photocatalytic water splitting. These results highlight the relationship between oxygen defects, electronic structure, and catalytic activity of perovskite LSCO, and demonstrate a rational approach to defect design and reveal the importance of anion redox chemistry for the structures and properties of perovskite oxides. Abstract : Defect engineering : A new method that controls the topochemical reaction between urea and perovskite is exploited to regulate oxygen defects in perovskite La0.5 Sr0.5 CoO3− δ (LSCO). Furthermore, introduction of more oxygen vacancies narrowed the overlap between Co 3d and O 2p, resulting in improvement of oxygen mobility and optimization of the relative location for the O p‐band center near the Fermi level, which are beneficial to improve catalytic properties such as carbon monoxide oxidation and photocatalytic water splitting activity (see figure).