Iron implantation as catalyst for oriented graphitic structures by developed Electron Beam Irradiation System (EBIS)

Full text: The search for new materials and modifications of existing materials have been the focus of scientific and technological researches. However, the obtainment method is an important point in materials science, since it directly influences the properties of materials [1]. According to this, this work has as main objective the insertion of iron in a carbon structure by the developed electron irradiation method in order to obtain catalytic oriented growth of carbon structures. For this, graphite pellets were irradiated for 2, 4, 8, 16 and 32 minutes by a developed Electron Beam Irradiation System (EBIS) under low vacuum with consequent sputtering of iron by a steel target placed along the electron beam pathway. The samples were characterized by micro-Raman, XPS, HRTEM, FIB-SEM and FESEM, followed by 3D reconstruction. As observed by FE-SEM analyzes, the electron irradiation with iron implantation led to remarkable morphological modifications, transforming random graphite in rod-like structures vertically disposed. HRTEM analyzes indicated the presence of fullerene structures, magnetite nanoparticles, carbon nanotubes and oriented graphite along the whole rod-like particle. Micro-Raman results indicated an evolution of structural disorder with increasing irradiation time until 8 minutes of irradiation and then decreases. This structural disorder arises from oxygen-bounded carbon that generates C sp3 orbitals, as corroborated by XPS analyzes. Therefore, the developed system successfully allowed the implantation of iron as catalyst for growth of oriented graphitic structures as vertically rod-like particles, enabling the reduction, morphological modifications and metals implantation of a wide range of materials. (author)