Enhanced oxygen reduction reaction performance of ReOx/NC (Re = La, Ce, Pr, Sm, Eu, Tb, Er, Tm and Yb)-especially Pr6O11/NC via accommodating oxygen vacancies and its application for Zn-air battery

ReOx/NC ORR catalyst with improved oxygen vacanices derived from heat treatment. [Display omitted] •The systematic comparisons of ORR activity with different rare earth have studied.•Pr6O11/NC presents the best ORR activity in studied rare earth.•The ORR activities of Pr6O11/NC are boosted with enhanced oxygen vacancies.•Zn-air battery constructed by Pr6O11/NC shows excellent performance. Rare earth metals have been widely investigated for oxygen reduction reaction (ORR) owing to their special 4f shell electronic configurations. However, the systematic comparisons of ORR activity with different rare earth have yet rarely studied. Herein, a series of rare earth (La, Ce, Pr, Sm, Eu, Tb, Er, Tm and Yb) oxides electrocatalysts were prepared with ketjin black EC300J as carbon support, in which the addition of rare earth is optimized. The ORR activities of different rare earth were evaluated by rotating disk electrode technology. The ORR performance of rare earth oxides composited carbon catalysts can be enhanced through accommodating oxygen vacancies. Then, the rare earth composite catalyst with the best ORR activities was chosen to detailed exploration. For practical application, the performance of rechargeable Zn-air battery was also researched. We believe that our work lay a good foundation to further explore rare earth based ORR catalyst with higher ORR performance.