Effects of Electrolytes on the Electrochemical Impedance Properties of NiPcMWCNTs-Modified Glassy Carbon Electrode

Abstract

The supercapacitive properties of synthesized nickel phthalocyanine multiwalled carbon nanotubes nanocomposite on a glassy carbon electrode (NiPcMWCNTs-GCE) in four different electrolytes were investigated. The successful synthesis of the NiPcMWCNTs nanocomposite was confirmed by UV/vis electrode spectroscopy, SEM, TEM, EDX, and XRD techniques. The supercapacitive behaviors of the modified electrodes were examined in PBS, H2SO4, Na2SO4, and SAB electrolytes via CV and EIS techniques. The highest specific capacitance of 6.80 F g−1 was achieved for the GCE-NiPcMWCNTs electrode in 5 mM [Fe(CN)6]4−/3− prepared in 0.1 M PBS (pH 7). Charge transfer resistance Rct values of 0.06, 0.36, 0.61, and 1.98 kΩ were obtained for the GCE- NiPcMWCNTs in H2SO4, SAB, Na2SO4, and PBS electrolytes, respectively. Power density values, otherwise known as the “knee” frequency f°, of 21.2, 6.87, 2.22, and 1.68 Hz were also obtained for GCE-NiPcMWCNTs in H2SO4, Na2SO4, PBS, and SAB electrolytes, respectively. GCE- NiPcMWCNTs demonstrated the fastest electron transport capability and the highest power density in H2SO4 compared to the other electrolytes. Hence, GCE-NiPcMWCNTs-modified electrodes had high stability, high energy and power densities, and a large specific capacitance.