Enhancing the Catalytic Activity of Zeolitic Imidazolate Framework-8-Derived N-Doped Carbon with Incorporated CeO2 Nanoparticles in the Oxygen Reduction Reaction

Graphical In the frame : Incorporating CeO 2 nanoparticles in zeolitic imidazolate framework-8 (ZIF-8) followed by high-temperature pyrolysis generated CeO 2 @N-doped carbon materials (see figure), which showed excellent activity in the oxygen reduction reaction, high tolerance to methanol crossover, and high stability. Incorporation of CeO 2 nanoparticles into the cavity of zeolitic imidazolate framework-8 (ZIF-8) was followed by high-temperature pyrolysis to generate CeO 2 @N-doped carbon materials. Introduction of the CeO 2 nanoparticles greatly enhanced the catalytic activity of the ZIF-8-derived carbon materials in the oxygen reduction reaction (ORR) owing to the presence of Ce 3+ and oxygen vacancies with high content of chemisorbed oxygen in CeO 2 and the well-maintained skeleton of the original ZIF-8 with uniform mesoporous structure. The material treated at 900 °C (CeO 2 @N-C-900) showed excellent ORR catalytic activity in both acidic and alkaline electrolyte. The ORR onset and half-wave potentials of CeO 2 @N-C-900 were 1.003 and 0.908 V versus RHE, respectively, in 0.1 m KOH aqueous solution, which are comparable to those of Pt/C catalysts. Furthermore, it exhibited much better stability and methanol crossover tolerance than Pt/C, indicative of its good potential for applications in energy conversion.