A waste to energy approach for the effective conversion of solid waste plastics into graphene nanosheets using different catalysts for high performance supercapacitors: a comparative study

Abstract

Presently, plastic waste management is an urgent issue around the globe that is not easy to resolve. We have made an attempt to resolve this issue by synthesizing graphene nanosheets (GNs), which are later exploited for supercapacitor applications. Herein, we report a multidimensional remediation approach for the mass scale production of GNs from plastic waste using zinc oxide (ZnO) and montmorillonite (MMT) clay as the catalysts and templates. Subsequently, supercapacitor (SC) cells are fabricated from the GNs synthesized using ZnO and MMT, and show good electrochemical performance with specific capacitances of 72.8 F g⁻¹ and 377.4 F g⁻¹, respectively. In addition, the GNs synthesized using MMT showed the highest energy and power densities of 21.1 W h kg⁻¹ and 1010.0 W kg⁻¹, respectively. Essentially, the use of MMT is able to mainly generate GNs with up to ∼2 layers from waste plastics; these GNs are more regular with less defects, which helps in enhancing the electrochemical performance of the cell. Thus, our study revealed that the choice of catalyst and template in a given GNs manufacturing process can alter the morphology and quality of the GNs, which ultimately affects their electrochemical performance in SC cells. We hope that this study can serve as a crucial breakthrough to deal with global threats such as plastic waste pollution and provide an economical option for the fulfilment of global energy demands.