Graphene nanosheets derived from waste plastic for cost-effective thermoelectric applications

Abstract

Herein, we report the synthesis of graphene nanosheets (GNs) derived from plastic waste for cost-effective thermoelectric (TE) applications. The synthesis of GNs was done as per our present process, where a two-step pyrolysis process was carried at the temperature range of 400 °C–850 °C by using Al2O3 as the catalytic and degradation template, while nickel metal-based catalytic beds were used to get high-quality GNs from our indigenously developed 100 Kg per batch pilot-scale plant. Raman, X-ray diffraction (XRD), and transmission electron microscopy (TEM) analysis showed the presence of 4–5 nm thick sheets of GNs. After the successful synthesis of GNs from waste plastics, the TE properties of thus synthesized GNs were investigated. GNs showed low resistivity of 3.93 × 10−2 Ω-m at room temperature, which are further decreases with an increase in temperature. The Seebeck coefficient values of the GNs show that the material behaves as a p-type semiconductor. The TE figure of merit ZT showed a signatory value of 0.1 × 10−6 at the temperature of 426 K corresponding to the TE properties within the synthesized GNs. The results of TE analysis indicate that waste plastic-derived GNs can be used for a variety of TE applications.