jp9b06061_si_001.pdf (1.46 MB)
Structure Determination of the Oxygen Evolution Catalyst Mössbauerite
journal contribution
posted on 2019-10-07, 19:48 authored by Pengbo Lyu, Michael Ertl, Christopher J. Heard, Lukáš Grajciar, A.V. Radha, Thomas Martin, Josef Breu, Petr NachtigallLayered
double hydroxides (LDHs) of various compositions have been
shown to be potent photo- and electrocatalysts. Recently, mössbauerite,
obtained by chemical oxidation of an all-iron, mixed-valence green
rust (GR) LDH, was introduced as an efficient oxygen evolution reaction
(OER) electrocatalyst. An accurate characterization of the structure
of mössbauerite is necessary for a knowledge-based future optimization
of OER performance. However, as is typical for layered materials,
massive defects hamper the understanding of its true structure. In
this work, we elucidate the structure of mössbauerite and gain
insight into the structure–property relationships relevant
to its potential as an OER catalyst. Density functional theory calculations
show that upon oxidation of a GR precursor to mössbauerite,
the direct grafting of interlayer anions to octahedral iron becomes
energetically feasible. This indicates that the grafted and interlayer
carbonate anions may coexist in a random interstratification. This
prediction is supported by analysis of infrared spectroscopy and X-ray
powder diffraction data, which show that an interstratified model
with turbostratic planar disorder provides a good fit with the experiment.
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OER performancetheory calculations showoctahedral ironOER catalystgain insightinterlayer anionsLDHGR precursorStructure Determinationinterstratified modelknowledge-based future optimizationX-ray powder diffraction dataoxygen evolution reactionchemical oxidationinterlayer carbonate anionselectrocatalyst
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