Nanometric nickel exsolution in the hexagonal perovskite Ba8Ta6NiO24: Survey of the structural, magnetic and catalytic features

JOURNAL OF ALLOYS AND COMPOUNDS

卷:766

Article; Proceedings Paper

Pussacq, Tanguy¹  Mentre, Olivier¹  Tessier, Franck²  Lofberg, Axel¹  Huve, Marielle¹  Caballero, Jesus Guererro¹  Colis, Silviu³  Kabbour, Houria¹ 

[1] Univ Lille, CNRS, ENSCL, Cent Lille,UCCS,Univ Artois,UMR 8181, F-59000 Lille, France

[2] Univ Rennes 1, UMR CNRS 6226, Inst Sci Chim Rennes, Verres & Ceram, 263 Ave Gen Leclerc, F-35042 Rennes, France

[3] Univ Strasbourg, CNRS, IPCMS, UMR 7504, 23 Rue Loess,BP 43, F-67034 Strasbourg 2, France

关键词: Oxide;    Hexagonal perovskite;    Ammonia;    Nickel;    Exsolution;   

DOI  :  10.1016/j.jallcom.2018.07.016

来源: Elsevier

【 摘 要 】

Nickel nanoparticles that decorate the surface of a parent oxide are well known to be developed by some cubic-type perovskites from the exsolution of their intrinsic Ni2+ species in reducing conditions with subsequent catalytic properties. In this work, we show similar phenomenon in a hexagonal-type perovskite. The reducing treatment in ammonia of Ba8Ta6NiO24, a hexagonal perovskite-type oxide, leads to the exsolution of nickel nano-sized particles at the surface of the precursor leaving oxygen vacancies and partially depleted but rearranged Ni/Ta sites. Spectroscopic methods, X-ray diffraction, TEM and TGA were employed to investigate the Ni exsolution while TGA was used to investigate the thermal behavior and its reversibility. 50% of the initial nickel content transferred into Ni-0 nanoparticles as determined from M(H) magnetization plots and TGA, in agreement with the concomitant creation of oxygen vacancies in the preserved Ni2(+) coordination (50%). The cationic vacancies (V-c) involve face-sharing octahedral dimers in which Ni/Ta/Vc rearranged through the shared face window, but preserved a non-centrosymmetric cationic partition. Ni exsoluted oxides often show a catalytic activity; we present here an original example of a hexagonal perovskite with catalytic activity toward syngas production by dry reforming of methane with carbon dioxide. (C) 2018 Elsevier B.V. All rights reserved.

【 授权许可】

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