A Doping‐Induced SrCo0.4Fe0.6O3/CoFe2O4 Nanocomposite for Efficient Oxygen Evolution in Alkaline Media

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 20; no. 21; pp. e2308948 - n/a
• Main Authors: Liu, Heng, Wang, Yuan, Tan, Pengfei, dos Santos, Egon C., Holmes, Stuart M., Li, Hao, Pan, Jun, D'Agostino, Carmine
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01-05-2024
• Subjects: Clean energy; Cobalt ferrites; Commercialization; density functional calculations; Doping; Electrocatalysts; Iron; Nanocomposites; Noble metals; oxygen evolution reaction; Oxygen evolution reactions; Perovskites; perovskite‐spinel nanocomposite; Spinel; Substrates; surface Pouribaix diagram
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.202308948

Perovskite and spinel oxides are promising alternatives to noble metal‐based electrocatalysts for oxygen evolution reaction (OER). Herein, a novel perovskite/spinel nanocomposite comprised of SrCo0.4Fe0.6O3 and CoFe2O4 (SCF/CF) is prepared through a simple one‐step method that incorporates iron doping into a SrCoO3‐δ matrix, circumventing complex fabrication processes typical of these materials. At a Fe dopant content of 60%, the CoFe2O4 spinel phase is directly precipitated from the parent SrCo0.4Fe0.6O3 perovskite phase and the number of active B‐site metals (Co/Fe) in the parent SCF can be maximized. This nanocomposite exhibits a remarkable OER activity in alkaline media with a small overpotentional of 294 mV at 10 mA cm−2. According to surface states analysis, the parent SCF perovskite remains in its pristine form under alkaline OER conditions, serving as a stable substrate, while the second spinel CF is covered by 5/8 monolayer (ML) O*, exhibiting considerable affinity toward the oxygen species involved in the OER. Analysis based on advanced OER microkinetic volcano model indicates that a 5/8 ML O* covered‐CF is the origin for the remarkable activity of this nanocomposite. The results reported here significantly advance knowledge in OER and can boost application, scale‐up and commercialisation of electrocatalytic technologies toward clean energy devices.
A novel perovskite/spinel nanocomposite, SrCo0.4Fe0.6O3/CoFe2O4 (SCF/CF), is prepared through a simple and straightforward method. The configuration and activity origin of the SCF/CF are analyzed by a theoretical framework, which integrates surface state analysis, work function computation, and microkinetic models. This proposed framework provides a theoretical methodology to investigate complex nanocomposites, particularly those affected by lattice mismatch challenges.