Tailoring Spin State of Perovskite Oxides by Fluorine Atom Doping for Efficient Oxygen Electrocatalysis

Abstract

Promoting the initially deficient but economical catalysts to high‐performing competitors is important for developing superior catalysts. Unlike traditional nano‐morphology construction methods, this work focuses on intrinsic catalytic activity enhancement via heteroatom doping strategies to induce lattice distortion and optimize spin‐dependent orbital interaction to alter charge transfer between catalysts and reactants. Experimentally, a series of different concentrations of fluorine‐doped lanthanum cobaltate (Fx‐LaCoO3) exhibiting excellent electrocatalytic activity is synthesized, including a low overpotential of 390 mV at j = 10 mA cm−2 for OER and a large half‐wave potential of 0.68 V for ORR. Meanwhile, the assembled rechargeable Zn–air batteries deliver an excellent performance with a large specific capacity of 811 mAh/gZn under 10 mA cm−2 and stability of charge/recharge (120 h). Theoretically, taking advantage of density functional theory calculations, it is found that the prominent OER/ORR performance arises from the spin state transition of Co3+ (Low spin state (LS, t2g6eg0) → Intermediate spin state (IS, t2g5eg1) and the mediated d‐band center upshift by F atom incorporation. This work establishes a novel avenue for designing superior electrocatalysts in perovskite‐based oxides by regulating spin states.

Regulation of the B Site at La(Ni0.1)MnO3 Perovskite Decorated with N-Doped Carbon for a Bifunctional Electrocatalyst in Zn–Air Batteries

“…O 2 -temperature programmed desorption (O 2 -TPD) was used to validate the crystal symmetry-induced active oxygen species, which is reliant on the binding strength between the adsorbed O 2 and adsorption sites (Figure c). The desorption peaks at 100–300, 300–400, 500–700, and above 700 °C were attributed to the chemical adsorbed oxygen O 2(ad) – , chemical adsorbed oxygen O (ad) – , subsurface lattice oxygen, and the evolution of bulk lattice oxygen, respectively. , La­(Ni 0.1 )­MnO 3 @NC exhibits a much larger desorption area, indicating more vacancies and abundant oxygen active sites . The different oxygen species in La­(Ni 0.1 )­MnO 3 @NC correspond to various oxygen p-band centers from [MnO 6 ] and [NiO 6 ], which contributes to the superior catalytic performance.…”

Engineering the spin configuration of electrocatalysts for electrochemical renewable conversions

“…95 From an electronic point of view, defect and doping strategies exhibit a positive effect on the electronic spin states. 89,96 In terms of the existence forms, defects can be roughly categorized as point, line, plane, and volume defects, among which point defects have been extensively researched in the context of electron spin electrocatalysis. Specifically, point defects can be formed by heteroatomic dopants, impurities, interstitial atoms and vacancies.…”

“…5c). 78,96,[108][109][110] Furthermore, the valence states of Mn in perovskite CaMnO 3Àd could be regulated via controlling hydrogen treatment and higher-valence-ion substituting, which was expected to optimize e g electron filling to 1. 111 Similar to defect engineering, heteroatom doping is another approach to tune spin electrocatalysis, which can generate a profound effect on the electronic properties and chemical activity of catalysts in a variety of ways.…”

“…Copyright 2023, Wiley. (c) The perovskite structure schematic image and CoO 6Àd polyhedron 96. Copyright 2020, Wiley (d)-(f) Diagrams showing the creation process for the modest deformation of the atomic arrangement brought about by the inclusion of heterogeneous spin states 97.…”

Rational element-doping of FeOOH-based electrocatalysts for efficient ammonia electrosynthesis

“…In addition, much literature indicates that atomic doping can introduce new active sites, and optimize the local charge distribution and electronic structure of the catalytic centers, which is a valid strategy to modulate the spin state of the materials. 29–34…”