Preparation of composite structures containing graphitic carbon nitride and hexagonal boron nitride; environmental and energy applications

Semiconductor nanocomposite materials have attracted intense interest for environmental remediation and energy applications in recent years. In this thesis, nanomaterial doped membranes and supercapacitors were produced. Graphitic carbon nitride (g-C3N4) and boron nitride quantum dots (BNKN) have been used as the main components of nanocomposite materials in these applications due to their high thermal stability and good dispersibility, chemical stability, electrical insulating properties and non-toxicity. The production of g-C3N4 and BNKN was carried out by heating process and hydrothermal treatment, respectively. In environmental applications of nanomaterials, polyethersulfone (PES) membranes (g-C3N4 @PES, BNKN@PES) containing 0.5 %, 1.0 % and 2.0 % by weight g-C3N4 or BNKN were produced in a casting unit. Along with the pure water flux permeability performance of the membranes, membrane fouling prevention and pollution studies were also investigated. It has been observed that hybrid membranes to display better cleaning properties than pure PES membranes. Graphene-based electrodes containing g-C3N4 or BNKN have been prepared for use in energy applications. In this context, electrodes (g-C3N4@rGOH ve BNKN@rGOH) that can be used in supercapacitor applications were prepared by hydrothermal treatment with reduced graphene oxide (rGO) (30 mg) of g-C3N4 or BNKN (15 mg / 30 mg / 60 mg), taken in different amounts, and with appropriate techniques (XRD, SEM, CV. BET, ZETA) were characterized. The specific capacitance values, impedance curves and charge/discharge performances of the electrodes produced from these hybrid structures were analyzed by electrochemical techniques. It was found that the electrode prepared g-C3N4@rGOH (at the ratio of 30 mg/15 mg) had the highest performance with a specific capacitance value of 157.4 F g-1. It was found that the hybrid structure of BNKN@rGOH (at the ratio of 30 mg/30 mg), prepared in equal proportions, had the highest performance with a specific capacitance value of 207.25 F g-1. According to the results obtained from this thesis study; It is seen that the hybrid structures produced are promising in environmental and energy applications.