LAUSR

Multilayer graphene-encapsulated iron nanoparticles in carbon frames were prepared through catalytic graphitization of kraft lignin as carbon sources using irons as the catalyst at the temperature of 1000°C under argon atmosphere. The effects of different iron loadings on the formation of multilayer graphene-encapsulated iron nanoparticles were investigated using thermogravimetric analysis and temperature-programmed decomposition. The evolution of gaseous products (H2, CH4, CO, and CO2) was measured using an online mass spectroscopy during the catalytic thermal decomposition of kraft lignin. Solid products were measured and characterized by elemental analysis, nitrogen adsorption, X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, and Raman spectroscopy. Thermogravimetric analysis curves indicated that peak temperatures of lignin decomposition and carbonization shifted to lower temperatures with an increase of iron/lignin mass ratio. Experimental results showed that the lignin graphitization degree and conversion level to graphene materials increased significantly with the increase of iron/lignin mass ratio.