A novel Ba0.5Sr0.5Co0.8Fe0.2O3−δ and CeO2 hybrid electrocatalyst for both the oxygen evolution and methanol oxidation reactions

Abstract

The catalytic properties of Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3−δ (BSCF) toward the oxygen evolution reaction (OER) and methanol oxidation reaction (MOR) are constrained by severe Sr segregation from the BSCF lattice. Herein, we address this problem by loading CeO₂ nanoparticles on the BSCF surface. Compared with pristine BSCF, the obtained hybrid catalyst (BSCF@CeO₂-10) with strong compressive stress shows greatly improved catalytic activity and stability toward both the OER and MOR. Furthermore, we deduce that the OER process on the BSCF@CeO₂-10 surface follows synergistic catalytic mechanism combining the adsorption evolution and lattice oxygen oxidation mechanisms. The greatly improved MOR catalytic activity of BSCF@CeO₂-10 can be ascribed to the deposition of CeO₂ facilitating the adsorption of methanol and reducing the overall energy barrier of the rate-determining step during *OCH₂ into *OCH. This work can provide new insights for designing novel perovskite electrocatalysts for both the OER and MOR.