3D-Graphitized and Iron Modified Carbon Aerogels for Sustainable Energy Applications

Abstract

3D-carbon aerogel nanomatrix has been modified with iron nitrate in the amounts of 10 and 20 wt. % by wet incipient method. The crystal structure, morphology, and electrocatalytic activity of the formed nanocomposites have been studied in comparison to the unmodified carbon aerogels after their heat-treatment at 900oC, 1200oC and 1400oC in argon. The mass and specific surface area losses in these materials reduced with iron doping is clear from BET isotherms and BJH pore size analysis. The HRTEM analysis confirms the presence of uniformly distributed ~43.5nm iron nanoparticles surrounded by graphite layers. The XRD analysis show that the level of graphitization increases with the sintering temperature and the concentration of the iron-containing phase. The ORR electrocatalytic activity studies demonstrate the influence of the heat-treatment temperature of samples on the ORR activity. Temperature programed reduction is carried out to understand the reduction behavior of these catalysts to metallic iron, to use them as substrates for direct CNT growth.