Fast electron transfer kinetics on novel interconnected nanospheres of graphene layers electrodes

A novel thin solid film of interconnected carbon nanospheres (ICNS) has been developed and characterized as electrode. The thin film is composed of interconnected carbon nanospheres with average crystallite size of ~ 5 nm and laminar graphene layers separated by an interplanar spacing of ~ 0.32 nm. An electrode was prepared in a one-step process by depositing ICNS onto a niobium substrate by hot filament chemical vapour deposition. To prepare an electrode, solvent-refined oil without additives was annealed up to 530 °C under ~ 2700 Pa of a gas mixture containing ethanol, methanol, water, and boron trioxide. The resulting ICNS film was characterized by scanning and transmission electron microscopy, plus Raman, Fourier transform infrared and energy dispersive spectroscopies. The contact angle between deionized water and the ICNS surface was zero - the water droplet instantaneously spread over the sample surface indicating a hydrophilic surface. The film behaviour as an electrochemical electrode was studied by cyclic voltammetry and electrochemical impedance spectroscopy. ICNS layers exhibited a large potential window, low uncompensated resistance, as well as low charge-transfer impedance in the presence of ferrocene-methanol or ferrocyanide as redox probes. These useful properties make ICNS electrodes very promising for future applications in electrocatalysis and (bio)sensors.