Effect of thermal condensation temperature on electrochemical capacitive properties of g-C3N4 supported on reduced TiO2 nanowires/nanotubes array

摘要： In this work, effect of processing temperature in electrochemical capacitors was investigated for g-C3N4. The g-C3N4 materials (CN) were synthesized by thermal condensation of melamine precursor at different temperature (450, 550 and 650 °C). Then, the g-C3N4 materials were deposited on electrochemically reduced TiO2 nanowires/nanotubes arrays (rTWTA)/Ti substrate. The g-C3N4/rTWTA/Ti electrodes were used as supercapacitor electrodes. Morphology, crystal structure and chemical composition of the g-C3N4/rTWTA/Ti electrodes were studied by FESEM, XRD, FTIR and elemental analysis. Based on galvanostatic charge/discharge measurements, the CN(450)/rTWTA/Ti electrode exhibited the highest specific capacitance up to 22 mF/cm2 at 0.3 mA/cm2 with long cyclic durability at 96.8% capacitance retention after 500 cycle. This effect was attributed to the existence of higher nitrogen content, more active sites, the improved hydrophilicity and three-dimensional morphology of the CN(450)/rTWTA/Ti electrode as compared to the other electrodes. This research introduces the optimum thermal condensation temperature of the melamine for synthesis of the g-C3N4 with great potentials in supercapacitors.