Operando X-ray characterization of interfacial charge transfer and structural rearrangements

Deeper mechanistic insights into epitaxial nickelate electrocatalysts for the oxygen evolution reaction

“…Yet, for epitaxial thin films, designing appropriate experimental cells is more challenging compared to conventional electrocatalyst materials because fabrication on X-ray-transparent membranes or a cell design with very thin liquid compartments are necessary to minimize attenuation of incoming and outgoing X-ray, as discussed in more detail elsewhere. 51 …”

“…Yet, for epitaxial thin films, designing appropriate experimental cells is more challenging compared to conventional electrocatalyst materials because fabrication on X-ray-transparent membranes or a cell design with very thin liquid compartments are necessary to minimize attenuation of incoming and outgoing X-ray, as discussed in more detail elsewhere. 51 In addition to studying activity trends, characterization of degradation pathways becomes increasingly important for selecting ideal electrocatalyst materials since an inverse activitystability relationship seems to exist as introduced previously. Akbashev et al 57 recently investigated the degradation of SrIrO 3 , a highly active electrocatalyst, during the oxygen evolution reaction (OER) using operando electrochemical atomic force microscopy (EC-AFM).…”

“…For electrocatalysts, this implies that true active phases and reaction sites do not ''pre-exist'' in asprepared ''pre-catalyst'' surfaces, but evolve under reaction conditions. 51 This will be discussed below in more detail for the case of NiO 2 -terminated LaNiO 3 from the example in Section 3.2. To achieve further understanding of the structure-property-function relationships governing electrocatalyst materials discovery, characterization of chemical composition, atomic arrangement and electronic structure of the interface under operating conditions is therefore necessary.…”