Facile one-pot hydrothermal synthesis of graphitic carbon nitride quantum dots integrated with tungsten trioxide-nanorods as a composite electrode material for supercapacitor applications

Carbon quantum dots have been remarkably used in recent research; these dot particles possess inherent properties, such as surface-to-volume ratio, greater surface area and an increased number of active sites, which enhance their applicability in various fields. Moreover, they are used as a potential material in energy storage, integrated with metal oxide to improve the performance of supercapacitor electrodes. Here, by employing the hydrothermal method, we synthesized and used gC 3 N 4 QDs (CNQDs) in conjunction with WO 3 nanorods (WOR) to form a composite material (WO-CN NC). CNQDs may act as a surfactant, thereby increasing the intensity of the XRD pattern of WO-CN NC. Numerous functional groups present in WO-CN NC facilitate the access of electrolyte ions during the electrochemical reaction. From Raman spectra, the increased value of I D /I G demonstrates that CNQD structures have a high degree of disorder or defects on their surface. The mesoporous nature and elevated surface area of WO-CN NC was observed owing to the incorporation of CNQDs. The presence of compositional elements and their binding energies were investigated using XPS analysis, and it confirms the presence of CNQDs in WO-CN NC. The morphology of FE-SEM and HR-TEM shows that WO 3 nanorods are embedded with CNQDs. Further, the incorporation of CNQDs in WO-CN NC shows an excellent electrochemical performance of 510.72C/g at a scan rate of 10 mV/s in CV analysis. This WO-CN NC electrode shows good cyclic efficiency of about 85 % after continuous 7000 GCD cycles. Further, an asymmetrical supercapacitor device (WO-CN NC//AC) is fabricated, which delivers an elevated specific capacity of 271C/g at 1 A/g with a maximum potential window of about 1.6 V. The WO-CN NC could be a potential electrode material appropriate for future energy storage applications.