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Facilitating the Deprotonation of OH to O through Fe4+‐Induced States in Perovskite LaNiO3 Enables a Fast Oxygen Evolution Reaction
Ist Teil von
Small (Weinheim an der Bergstrasse, Germany), 2021-03, Vol.17 (12), p.e2006930-n/a
Ort / Verlag
Weinheim: Wiley Subscription Services, Inc
Erscheinungsjahr
2021
Link zum Volltext
Quelle
Wiley Online Library Journals Frontfile Complete
Beschreibungen/Notizen
Aliovalent doping is widely adopted to tune the electronic structure of transition‐metal oxides for design of low‐cost, active electrocatalysts. Here, using single‐crystalline thin films as model electrocatalysts, the structure‐activity relationship of Fe states doping in perovskite LaNiO3 for oxygen evolution reaction (OER) is studied. Fe4+ state is found to be crucial for enhancing the OER activity of LaNiO3, dramatically increasing the activity by six times, while Fe3+ has negligible effect. Spectroscopic studies and DFT calculations indicate Fe4+ states enhance the degree of Ni/Fe 3d and O 2p hybridization, and meanwhile produce down‐shift of the unoccupied density of states towards lower energies. Such electronic features reduce the energy barrier for interfacial electron transfer for water oxidization by 0.2 eV. Further theoretical calculations and H/D isotope experiments reveal the electronic states associated with Fe4+‐O2−‐Ni3+ configuration accelerate the deprotonation of *OH to *O (rate‐determining step), and thus facilitate fast OER kinetics.
Perovskite LaNiO3 is an efficient electrocatalyst for oxygen evolution reaction (OER). However, the OER activity is limited by the deprotonation of *OH to *O as rate determining step. Introducing Fe4+ states into LaNiO3 (Ni3+‐O2‐‐Fe4+ configuration) can accelerate the deprotonation step, and thus promoting OER kinetics.