Effects of Ce doping on specific capacitance of ZIF-8 derived carbon

A simple and efficient method to synthesize Ce-doped and N-incorporated carbon electrodes derived from zeolite imidazole frameworks-8 (CeO 2 -NCs) has been demonstrated for the first time, taking advantages of the synergistic effects of metal-organic frameworks, carbon materials and rare earth element , Ce. A series of characterizations of surface morphology and electrochemical performance of the NC samples fabricated with different Ce contents and calcination temperatures, demonstrate that appropriate Ce-doping in the 3D-Rhombic dodecahedron NC structure through calcination at a suitable temperature (450 °C) can efficiently enhance the electrochemical performance of the NC material: CeO 2 /NC-32–450 shows a high specific capacitance of 275.3 F g −1 at 0.5 A g −1 using 6.0 M KOH electrolyte, and a superior capacity retention of 90.7 % after 5000 cycles at a current density of 10 A g −1 . Further morphological and microstructural analyses by various characterization techniques revealed that the improved specific capacitance is not by the change in its surface morphology and pore structure , but owing to an increase in the relative concentration of sp 2 C C groups, graphitic-N and quaternary-N, as well as the synergistic effect of the redox performance of Ce 4+ -Ce 3+ for rapid charging/discharging upon Ce-doping. Therefore, the proposed Ce-doped NC has strong potential for applications in supercapacitors . • A simple and efficient method to synthesize CeO 2 -NCs was demonstrated. • Appropriate Ce-doping at suitable temperatures can enhance the performance. • High specific capacitance of 275.3 F g −1 with superior capacity retention was obtained. • The content of sp 2 C C groups, graphitic-N and quaternary-N affect specific capacitance. • The redox performance of Ce 4+ -Ce 3+ conduces to rapid charging/discharging.