Graphene nanosheets derived from plastic waste for the application of DSSCs and supercapacitors

The present study reports the upcycling process of waste plastics into value-added product graphene nanosheets (GNs) and their subsequent applications in dye sensitized solar cells (DSSCs) and supercapacitors.Bentonite nanoclay has been used as an agent for the degradation of waste plastics with two step pyrolysis processes at 450 °C and 945 °C in an inert atmosphere of N 2 gas to obtain GNs.The GNs with few layers were confirmed by the RAMAN spectroscopy, XRD and HRTEM analyses.Further, FT-IR and EDX analyses also performed for the identification and quantitative analysis of functional groups in GNs.The GNs thus synthesized from plastic waste have been used for the fabrication of DSSCs and supercapacitors.The DSSC fabrication with GNs as part of photo-anode with polymeric electrolyte showed a high fill factor of 86.4% and high V oc of 0.77 V, which were also supported by the computational findings.On the other hand, the utilization of GNs as an active layer material of supercapacitor electrodes offered a high specific capacitance of 398 F/g with a scan rate of 0.005 V/s.The supercapacitor also exhibited significant energy density (E d ) and power density (P d ) of 38 Wh/kg and 1009.74W/kg, respectively.Thus, the process illustrated the utility of waste plastics upcycling for conservation of EEE i.e., ecology, economy and energy for better tomorrow.The demand for sustainable green energy and eco-friendly upcycling of plastic waste with attractive industrial symbiosis and cost benefit analysis are the biggest challenges of the twenty first century.Both these issues must be resolved in order to address the problems associated with the production of clean energy and sustainable protection of the ecology and economy from plastic waste.In a circular economy, transition is a common factor, and the word "waste" can be replaced by "resource material" as the waste is used as feedstock materials in various processes 1 .In this way, the waste materials act as resource materials, and cascade proper synergistic economic and societal benefits along with sustainable environmental management [2][3][4][5][6][7] .The future of sustainable environmental management also depends on the scale of deployment of the renewable energy production and storage technology.In this regard, the production of solar energy through utilization of photovoltaic technology is one of the most prominent ways to generate sustainable green energy 8 .Among photovoltaic technologies, the dye sensitized solar cell (DSSC) stands as a promising candidate for the production of greener energy due to its ease of fabrication 9 .Yet, the research on DSSC is mainly focused for the outdoor applications.The development of DSSC for indoor applications through materials that can harvest energy even in the presence of dim lighting is an important research aspect 10 .Hence, the research for developing DSSCs using greener and cost-effective materials is on the rise.In the last decade, the incorporation of conducting polymers, transition metal composites, and carbon based nanomaterials in DSSCs has increased considerably [11][12][13][14][15][16][17][18][19][20][21][22] .The carbon based nanomaterials such as graphene, carbon nanotubes (CNTs), and carbon OPEN