Engineering

Computational chemistry

Physical chemistry

Density functional theory

Ionic liquid

Perovskite (structure)

Catalysis

Electrode

Organic chemistry

Inorganic chemistry

Chemistry

Metallurgy

Materials science

Ionic bonding

Oxide

Chemical engineering

Electrochemistry

Metal

Biochemistry

Crystallography

Electronic structure

Applied Catalysis B Environment and Energy

Perovskite oxides have been intensively studied for electrochemical catalysis, due to their tunable composition, low cost, and strong structure-activity relationship. Here we report a novel and facile strategy to enhance the ORR activity and stability of Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) perovskite oxide through engineering the surface electronic structure with ionic liquid (IL). BSCF-IL shows a boosted intrinsic activity ∼2.7 times that of BSCF, with a positively shifted half-wave potential by 40 mV and significantly improved stability. The enhancement is attributed to the strong electronic interaction between BSCF and IL, which triggers the surface amorphization and selective elemental preservation, promoting the exposure of active sites. Synchrotron-based X-ray absorption spectroscopy and density functional theory calculations reveal the charge transfer from BSCF to IL and the oxidation of surface Co and Fe, leading to the optimized eg filling, lifted O-2p band center and improved metal 3d-O 2p hybridization, contributing to higher ORR catalysis.

Engineering the electronic structure of perovskite oxide surface with ionic liquid for enhanced oxygen reduction reaction