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

• Simple and non-alkali reagent hydrothermal synthesis of nanostructured CeO 2 (HC) • Plasma engraving to prepare rich-oxygen vacancies electrode of Bi@CeO 2 (PBC) • At 10 mA cm −2 , the HC electrode displays a low overpotential of 0.32 V, Excellent stability of 99.6 % for 15 h. • The PBC electrode exhibits a low overpotential of 0.46 V at a current density of 250 mA cm −2. • Excellent stability of 99 % for 15 h at a current density of 100 mA cm −2. Herein, pristine nanostructured cerium oxide (CeO 2 ) 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@CeO 2 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 CeO 2 and its composite Bi@CeO 2 are promising potential active OER electrocatalysts.