Séminaire du Docteur Xi Cheng - PSI (Suisse)

Date: 2018-03-28 10:00

Lieu: bibliothèque AIME, 1er étage, bât 15

Oxygen Evolution Reaction on Perovskites: A Combined Experimental and Theoretical Study of Their Structural, Electronic, and Electrochemical Properties 

Perovskite Oxides (ABO3) with alkaline or rare-earth cations in the A-site and first row transition metal cations in the B-site have shown the potentials of being viable oxygen electrode catalysts in alkaline solution 1. Furthermore, it was demonstrated that their physical-chemical properties as well as their catalytic activity can be significantly influenced by substitution or partial substitution of the A and/or B-site by other elements giving (AxA’1-x)(ByB’1-y)O3 compositions. However, it is a difficult task to find the most active oxides among the many different families of perovskites. A descriptor-based analysis can provide a promising approach to predict and identify the most active materials, since it correlates the prospective electrocatalytic activity to other, simpler properties. In the present work, the crystallographic structure, bulk electronic structure, conductivity and electrochemical activity toward the oxygen evolution reaction for two perovskite series (La1‑xSrxCoO32 with x=0, 0.2, 0.4, 0.6, 0.8, 1 and LaBO3 with B=Cr, Mn, Fe, Co, Ni) are investigated experimentally and theoretically. Experimental characterizations (XRD, XAS, neutron diffraction, ex-situ electronic conductivity and OER measurements) demonstrate that the varying of the A‑site and B‑site delivers several changes in the physicochemical properties of the considered oxides. But by combining experiments with density‑functional theory calculations, we show that it is possible to reliably relate some simple physico-chemical materials properties including the electronic structure to the observed activity towards the oxygen evolution reaction. However, the correlation between the OER activity with one physico-chemical materials property presents always some deviation points, indicating the limit of the 2-Dimension correlation. Hence, we try to correlate the OER activity with several physico‑chemical materials properties at the same time and leading to a 3-Dimension correlation. This correlation might facilitate the search and design of highly active oxygen evolution catalysts, in the quest for efficient anodes in water electrolyzers. 
1. E. Fabbri, A. Habereder, K. Waltar, R. Kotz, T.J. Schmidt, Developments and perspectives of oxide-based catalysts for the oxygen evolution reaction. Catal Sci Technol 2014, 4 (11), 3800-3821.
2. X. Cheng, E. Fabbri, M. Nachtegaal, I. E. Castelli, M. E. Kazzi, R. Haumont, N. Marzari, and T. J. Schmidt, Oxygen Evolution Reaction on La1−xSrxCoO3 Perovskites: A Combined Experimental and Theoretical Study of Their Structural, Electronic, and Electrochemical Properties. Chem. Mater. 2015, 27, 7662-7672.  

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Toutes les Dates

  • 2018-03-28 10:00

Propulsé par iCagenda

Institut Charles Gerhardt Montpellier - Direction

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