Defect Engineering, Electronic Structure, and Catalytic Properties of Perovskite Oxide La_0.5Sr_0.5CoO_3−δ

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 La Sr CoO (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.

Amorphous Boron Dispersed in LaCoO3 with Large Oxygen Vacancies for Efficient Catalytic Propane Oxidation

“…Perovskite is a promising alternative to noble metal catalysts for VOCs catalytic oxidation, attracting scholarly attention owing to the features of its variable chemical components and high thermal stability [4] . However, the low specific surface area of perovskite resulting from the high synthesis temperature reduces the adsorption and reaction ability of the substrate gas on the active sites.…”

Switchable Intrinsic Defect Chemistry of Titania for Catalytic Applications

“…In particular, defect engineering serves as a platform to tailor the intrinsic electrons of materials and, hence, to tune their properties, reactivity, and catalytic activity [2][3][4][5][6][7][8][9][10][11][12][13]. The past centuries have witnessed significant progress towards commercialization of water-splitting technologies predominantly due to the intentional creation of defects in various catalytically in-active materials [14][15][16][17][18][19][20][21][22], but still, we are distant from the basic understanding of structural defects and the critical parameters which play an essential role in water-splitting applications. The grand challenge lies in the development of an improved catalyst for water-splitting applications.…”

Enhanced CO catalytic oxidation by Sr reconstruction on the surface of La x Sr 1− x CoO 3− δ

“…To manufacture more oxygen vacancies on the basis of the original structure, a majority of method use medium or high temperature annealing under reducing atmosphere (H 2 , NH 3 , C 2 H 4 and C 3 H 6 ) at present [6,27]. However, this annealing method is energy intensive and raises the cost of production in commercial applications and it is very difficult for the samples with a strong redox property such as La x Sr 1Àx CoO 3Àd to reasonably control oxygen defects [28]. Meanwhile, high temperature sinter is easy to decrease its specific surface area and increase the coverage of surface secondary phase.…”