Mechanisms of the Oxygen Evolution Reaction on NiFe2O4 and CoFe2O4 Inverse-Spinel Oxides

Alessandro Fortunelli

Consiglio Nazionale delle Ricerche
Area della Ricerca Pisa, Italy

Monday, 12th December 2022,16:15 s.t.

The talk will be given in hybrid mode.

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Josef Loschmidt Hörsaal (HS 2)
University of Vienna, Faculty of Chemistry
Währinger Straße 42, 1090 Vienna

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Mechanisms of the Oxygen Evolution Reaction on NiFe2O4 and CoFe2O4 Inverse-Spinel Oxides

Water electrolysis in the form of Anion Exchange Membrane Water Electrolysis is a well-established method to produce hydrogen from the renewable energy sources, whose implementation at the global level is hindered by the sluggish anodic oxygen evolution reaction (OER). In the search of efficient and non-critical-raw-material OER catalysts, spinel oxides are promising, but experiments on catalytic performance and stability are scattered over a wide range depending on protocols of materials preparation and treatment. To overcome this impasse and provide fundamental knowledge in the field, we conduct an extensive DFT investigation of OER energetics and reaction paths over the (001) facets of two spinel oxides: Nickel ferrite, NiFe2O4, and Cobalt ferrite, CoFe2O4. By cataloguing a wide set of intermediates and mechanistic pathways, including lattice oxygen mechanism (LOM) and adsorbate evolution mechanism (AEM), along with the rate-determining barriers  and transition-state structures, we computationally predict turnover frequencies (TOFs) in fair agreement with experimentally reported data, and suggest CoFe2O4 as a more promising OER catalyst than NiFe2O4 in the pristine case, a finding that may offer a basis for further progress and optimization. Then, by including other low-index facets [(110) and (111)], we also predict nanoparticle reshaping under diverse environment and operating conditions, as well as discuss the possibility and challenges of operando monitoring of these promising OER catalysts.

Bio of Alessandro Fortunelli​

Alessandro Fortunelli is Research Director National Research Council (CNR) in Pisa in Italy. He received his Ph.D. in Chemistry at Scuola Normale Superiore Pisa (2012). He held previous positions at CNR since 1984, was a visiting scientist at the University of California at Los Angeles (UCLA, 2001) and at Caltech (2003-2004), and is a visiting associate at Caltech since 2012. Alessandro held and holds leading positions in large research projects such as FP6, FP7, and H2020 projects. He is author of more than 280 refereed publications and peer reviewer for 22 international journals. He describes his research goal as “a predictive computational science of structural, catalytic, magneto-optical, mechanical, and transport properties, with applications in the field of energy and environment.”