(558ca) Sol Gel Prepared Fe and Ni Based Catalyst for Pyrolysis-Catalysis of Waste Plastics for Hydrogen and Carbon Nanotubes

Compared with incineration and landfills, chemical recycling of waste plastics is becoming more attractive in terms of sustainable development. In this work, waste plastics was thermal chemically treated with a pyrolysis-catalysis process for the production of hydrogen and high value added carbon nanotubes. A novel sol gel method was accepted to prepare catalyst for this process, and the effect of catalyst composition on the produced gas and solid were investigated. Results suggest that Fe catalyst generated higher production of hydrogen and carbon nanomaterials than Ni catalyst, due to the higher decomposition and carbon solubility. High-resolution transmission electron microscopic analysis show that the generated carbon materials from waste polypropylene was mainly multi-walled bamboo-like carbon nanotubes, with outer diameter varied from 15 to 30 nm and layer number between 10 and 25. The introduction of Ni to the Fe catalyst was found to significantly improve the catalyst activity, with an optimal hydrogen yield of 25.12 mmol g^-1_plastic and concentration of 56.52 vol. %. Furthermore, both Raman and X-ray diffraction characterizations indicate that the purity and graphitization were also increased at the presence of Ni modified Fe catalyst. In addition, this kind of catalyst was further investigated for pyrolysis of low density polyethylene, high density polyethylene, polystyrene and real world plastic mixture, in order to explore the catalytic activity and sensitivity to different plastic feedstock. Results suggest that the sol gel prepared Ni modified Fe catalyst was highly efficient for simultaneous production of hydrogen and carbon nanotubes from various plastic wastes.