Boosting oxygen evolution electrocatalysis via CeO 2 engineering on Fe 2 N nanoparticles for rechargeable Zn-air batteries.

In the process of developing low-cost and high-performance bifunctional electrocatalysts, rational selection of catalytic components and tuning of their electronic structures to achieve synergistic effects is a feasible approach. In this work, CeO 2 was composited into Fe/N-doped carbon foam by a molten salt method to improve the electrocatalytic performance of the composite catalyst for the oxygen evolution reaction (OER). The results showed that the excitation of oxygen vacancies in CeO 2 accelerated the migration of oxygen species and enhanced the oxygen storage/release capacity of the as-prepared catalyst. Meanwhile, the size effect of CeO 2 particles enabled the timely discharge of gas bubbles from the reaction system and thus improved the OER kinetics. In addition, a large number of pyridine-N species were induced by CeO 2 -doping and sequentially anchored in the carbon matrix. As a result, the Fe 2 N active state was formed through the strengthened binding of Fe-N elements. Benefiting from the strong electronic interaction between Fe 2 N and CeO 2 components, the optimal CeO 2 -Fe 2 N/NFC -2 catalyst sample showed a good OER performance ( E j =10 = 266 mV) and ORR electrocatalytic activity ( E 1/2 = 0.87 V). The practical feasibility tests indicated that the Zn-air battery assembled by the CeO 2 -Fe 2 N/NFC -2 catalyst exhibited a large energy density and an excellent long-term cycling stability.