Synthesis of porous carbon and porous graphene from metal-organic framework and their electrochemical properties

Abstract

One non porous MOF (MOF-235) and one highly porous MOF (amino-MIL-101) were synthesized as starting precursors to get carbon materials by using these MOFs as template and also by direct carbonization. The application of aminofunctionalized MOF was also investigated for water purification. Harmful dyes (both cationic and anionic dyes) can be efficiently removed from contaminated water by the amino-functionalised MOF, amino-MIL-101(Al). This MOF showed a superior adsorption capacity to remove cationic dyes than any other MOFs reported in the literature. Nanoporous graphenes with high surface area were synthesized using a metal-organic framework (non porous MOF) a template with furfuryl alcohol as well as by direct carbonization technique. This new synthesis technique is very simple and one step process to get nanoporous graphene. The graphene synthesized by this process showed excellent electrochemical properties as an electrode materials for electric double layer capacitor. The capacitor made up with this nanoporous graphene displayed excellent capacity retention over 10000 cycles. On the other hand, highly porous N-doped carbons were synthesized by carbonizing an amino-functionalized metalorganic framework (porous MOF) using a template with furfuryl alcohol as well as by the direct carbinization. A series of N-doped porous carbon were investigated to examine its electrocatalytic properties based on different nitrogen sites. A particular nitrogen type containing carbon materials shows an activity as excellent electrocatalyst among the different types of N functionalities including pyrrolic N, pyridinic N, quaternary N and pyridinic N-oxide. This allowed the impact of quaternary N on the electrocatalytic activity for oxygen reduction to be assessed in a series of related N-doped carbons. Only the quaternary-N-containing N-doped carbon catalyzed the four-electron reduction of O2, offering insight into the active site for reaction. This synthesized highly porous N-doped porous carbon also displayed remarkable capacitance properties as double layer capacitor than non doped porous carbon reported in the literature. The capacitor made up with this nanoporous carbon displayed poor capacity retention over 5000 cycles compared with porous graphene.