High-performance oxygen evolution reaction activity at low and higher current densities using nanostructured CeO₂ and Plasma-assisted Bi@CeO₂ electrocatalysts

Herein, pristine nanostructured cerium oxide (CeO₂) electrode (HC) was fabricated via an alkali-free hydrothermal, exhibiting high OER behaviors at low current density. The HC electrode displayed a low overpotential of 0.32 V, low Tafel slope of 61.6 mV dec^-1, and high stability of 99.6 % for 15 h at a current density of 10 mA cm⁻². To accelerate the kinetic of OER at high current density, a binary Bi@CeO₂ plasma-activated electrode (PBC) was prepared as an effective electrocatalyst to evolve larger oxygen gas. The PBC electrode exhibited a low overpotential (0.42 V and 0.46 V) at higher current densities of 50 mA cm⁻² and 250 mA cm⁻², a small Tafel slope of 47.4 mV dec^-1, and excellent stability of 99 % for 15 h at a current density of 100 mA cm⁻². The results suggested that CeO₂ and its composite Bi@CeO₂ are promising potential active OER electrocatalysts.