The partial substitution of A-site in perovskites is a major strategy to enhance the catalytic oxidation activity. This study explores the use of silver (Ag) to partially replace the lanthanum (La) ion at the A-site in LaCoO perovskite, investigating the role of Ag in the ABO perovskite structure, elucidating the nitric oxide (NO) oxidation mechanism over LaAgCoO (x = 0.1-0.5) perovskites. LaAgCoO with an Ag-doping amount of 0.3, exhibited the highest NO oxidation activity of 88.5% at 275 °C. Characterization results indicated that Ag substitution enhanced the perovskite, maintaining its original phase structure, existing in the form of a mixture of Ag and Ag in the LaAgCoO (x = 0.1-0.5) perovskites. Notably, Ag substitution improved the specific surface area, reduction performance, Co, and surface adsorption oxygen content. Additionally, the study investigated the relationship between magnetism and NO oxidation from a magnetism perspective. Ag-doping strengthened the magnetism of La-Ag perovskite, resulting in stronger adsorption of paramagnetic NO. This study elucidated the NO oxidation mechanism over La-Ag perovskite, considering structural and magnetic properties, providing valuable insights for the subsequent development and industrial application of high oxidation ability perovskite catalysts.
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http://dx.doi.org/10.1016/j.jenvman.2024.120160 | DOI Listing |
Molecules
December 2024
Inner Mongolia Key Lab of Solid State Chemistry for Battery, Inner Mongolia Engineering Research Center of Lithium-Sulfur Battery Energy Storage, College of Chemistry and Materials Science, Inner Mongolia Minzu University, Tongliao 028000, China.
In the era of artificial intelligence and Internet of Things, data storage has an important impact on the future development direction of data analysis. Resistive random-access memory (RRAM) devices are the research hotspot in the era of artificial intelligence and Internet of Things. Perovskite-type rare-earth metal oxides are common functional materials and considered promising candidates for RRAM devices because their interesting electronic properties depend on the interaction between oxygen ions, transition metals, and rare-earth metals.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Department of Materials Science and Engineering, Chosun University, Gwangju 61452, Korea.
With the applications of in situ X-ray diffraction (XRD), electrical - measurement, and ambient pressure hard X-ray photoelectron spectroscopy (AP-HAXPES), the characteristics of the topotactic phase transition of LaCoO (LCO) thin films are examined. XRD measurements show clear evidence of structural phase transition (SPT) of the LCO thin films from the perovskite (PV) LaCoO to the brownmillerite (BM) LaCoO phases through the intermediate LaCoO phase at a temperature of 350 °C under high-vacuum conditions, ∼10 mbar. The reverse SPT from BM to PV phases is also found under ambient pressure (>100 mbar) of air near 100 °C.
View Article and Find Full Text PDFPhys Chem Chem Phys
December 2024
School of Physics, Hangzhou Normal University, Hangzhou, Zhejiang 311121, China.
Oxygen vacancy (V) formation in perovskites plays an important role in improving their functional applications. Using density functional theory calculations, we investigated the effect of sulfur (S) doping on V formation in LaBO (B = Fe, Co, and Ni) perovskites, considering the HS, IS, and LS states of Co ions in LaCoO to examine the influence of spin states. Our results show that the weaker electronegativity of S than that of O leads to a decrease in the magnetic moment of B atoms directly adjacent to the substituted S and an increase in the electrical conductivity of insulating systems.
View Article and Find Full Text PDFACS Appl Mater Interfaces
December 2024
Xi'an Key Laboratory of Functional Supramolecular Structure and Materials, College of Chemistry and Material Science, Northwest University, Xi'an 710127, China.
The oxygen evolution reaction (OER) poses a significant kinetic challenge for various critical energy conversion and storage technologies including electrocatalytic water splitting and metal-air batteries. In this study, a LaCoO/NiFe layered double hydroxide (LDH) catalyst was synthesized through the growth of n-type NiFe LDH on the surface of the p-type LaCoO semiconductor, resulting in a p-n heterostructure for a photogenerated carrier-assisted electrocatalytic OER (PCA-eOER). The alignment of their band structures facilitates the formation of an internal electric field at the heterojunction interface, which promotes the creation of oxygen vacancies and enhances electron transport.
View Article and Find Full Text PDFJ Colloid Interface Sci
February 2025
State Key Laboratory for Mechanical Behavior of Materials, School of Materials Science and Engineering, Xi'an Jiaotong University, Xi'an 710049, China. Electronic address:
The rising global energy demand & environmental crisis spur exploration of traditional fuel alternatives. Hydrogen, with high energy density & pollution-free potential, is seen as a promising energy carrier. The development of efficient and durable electrocatalysts for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is of paramount importance for renewable energy conversion and storage systems.
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