Alkaline water electrolysis based on durable electrocatalysts made from Earth-abundant metals like nickel is a crucial energy storage technology for the transition to renewable energy. Enabling the observation of active catalytic species under working conditions by monitoring the surface oxidation state and local atomic structure transformation, operando characterization techniques can probe the active sites and promote a fundamental understanding of the reaction mechanisms. We introduce a technique merging the pair distribution function (PDF), principal-component analysis, and operando electrochemistry to investigate the electrocatalyst NiGraf, which is composed of graphene oxide entrapped in nickel-based nanoparticles, during the oxygen evolution reaction. The operando investigation of the electrocatalyst uses synchrotron X-ray powder diffraction and PDF. Structural changes in the crystal phases of the nanomaterial during voltammetry cycles in the oxygen evolution reaction range revealed first a reversible variation in the distance between graphene oxide planes and a subsequent irreversible activation stage of the electrocatalyst.
Structural dynamics of a nickel electrocatalyst during water splitting observed via the operando pair distribution function
Caliandro R.;Berretti E.;Pagliaro M. V.;Ciriminna R.;Mangini V.;Giannini C.;Lavacchi A.;Pagliaro M.
2024
Abstract
Alkaline water electrolysis based on durable electrocatalysts made from Earth-abundant metals like nickel is a crucial energy storage technology for the transition to renewable energy. Enabling the observation of active catalytic species under working conditions by monitoring the surface oxidation state and local atomic structure transformation, operando characterization techniques can probe the active sites and promote a fundamental understanding of the reaction mechanisms. We introduce a technique merging the pair distribution function (PDF), principal-component analysis, and operando electrochemistry to investigate the electrocatalyst NiGraf, which is composed of graphene oxide entrapped in nickel-based nanoparticles, during the oxygen evolution reaction. The operando investigation of the electrocatalyst uses synchrotron X-ray powder diffraction and PDF. Structural changes in the crystal phases of the nanomaterial during voltammetry cycles in the oxygen evolution reaction range revealed first a reversible variation in the distance between graphene oxide planes and a subsequent irreversible activation stage of the electrocatalyst.File | Dimensione | Formato | |
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