Bifunctional electrochemical properties of La0.8Sr0.2Co0.8M0.2O3−δ (M = Ni, Fe, Mn, and Cu): efficient elemental doping based on a structural and pH-dependent study

Perovskite oxides with a low cost and high catalytic activity are considered as suitable candidates for the oxygen evolution reaction (OER)/oxygen reduction reaction (ORR), but most of them favour only either the ORR or the OER. Besides, their underlying catalytic mechanisms are subject of an ongoing debate. Herein, La0.8Sr0.2CoO3−δ (LSC) was selected as a base perovskite oxide for doping different elements into its B-site to fabricate four different La0.8Sr0.2Co0.8M0.2O3−δ (LSCM; M = Ni, Fe, Mn, and Cu) perovskite oxides. Among the catalysts tested with and without multi-walled carbon nanotubes (MWNTs), La0.8Sr0.2Co0.8Fe0.2O3−δ (LSCF) outperformed any other catalysts in terms of both OER and ORR activity. The OER/ORR activity enhancement with LSCF is also discussed based on spectroscopic and microscopic analyses and lattice oxygen transportation.