The production and electrochemical performance of carbon nano-materials derived from plastics over nickel-based catalysts with different supports

Abstract

This paper demonstrates a promising method for converting waste plastics into high-value carbon nano-materials as electrode materials. Therein, the catalytic performances of the three catalysts with different supports (Ni/γ-Al2O3, Ni/CaO and Ni/MgO) for carbon nano-materials derived from the catalytic cracking of low-density polyethylene in a two-stage reaction system were investigated. Compared with other carbon precursors, the hydrogen in the pyrolysis gas from plastics facilitated the growth of CNTs. Through the analysis of the physicochemical properties, the γ-Al2O3 support could improve the dispersion of NiO, which was beneficial to increasing the yield and uniformity of CNTs. The proper interaction of NiO with the γ-Al2O3 was conducive to improving the degree of graphitization of CNTs. The results showed that CNTs-A (from Ni/γ-Al2O3) obtained a specific capacitance of 32 F g−1 (0.5 A g−1, 6 M KOH), compared to CNTs-C (from Ni/CaO) and CNTs-M (from Ni/MgO) increased by 23% and 68%, respectively. It was demonstrated that CNTs-A with fewer defects, large specific surface area and high graphitization properties could achieve higher electrochemical performance by reducing the resistance during electron transfer.