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

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, H 2 SO 4 , Na 2 SO 4 , 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 R ct values of 0.06, 0.36, 0.61, and 1.98 kΩ were obtained for the GCE-NiPcMWCNTs in H 2 SO 4 , SAB, Na 2 SO 4 , 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 H 2 SO 4 , Na 2 SO 4 , PBS, and SAB electrolytes, respectively. GCE-NiPcMWCNTs demonstrated the fastest electron transport capability and the highest power density in H 2 SO 4 compared to the other electrolytes. Hence, GCE-NiPcMWCNTs-modified electrodes had high stability, high energy and power densities, and a large specific capacitance.