Fabrication of Carbon-Doped Titanium Dioxide Nanotubes as Anode Materials for Photocatalytic Glucose Fuel Cells

In the present work, TiO₂ nanotubes (TNT) and carbon-doped TiO₂ nanotubes (C-TNT) were produced via the anodization method. Carbon doping was performed on TNT in a tubular oven employing two different 15 cm³/min total flow rates with varying compositions of acetylene (C₂H₂) and argon (Ar) as V_C2H2/Ar = 7/93 (1 cm³/min C₂H₂ + 14 cm³/min Ar) for C-TNT (7:93) and V_C2H2/Ar = 33/67 (5 cm³/min C₂H₂ + 10 cm³/min Ar) for C-TNT (33:67). The synthesized C-doped TNT was characterized by x-ray diffraction (XRD), Raman spectroscopy, and scanning electron microscopy (SEM). XRD, Raman spectra, and SEM results reveal that a carbon film structure was formed on the TNT surface. In addition, the electronic structure of TNT changed with doping of carbon on the TNT surface. These carbon-doped TNTs were employed as catalysts for the photocatalytic oxidation of glucose (GA). Cyclic voltammetry (CV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS) measurements were carried out to investigate the glucose electro-oxidation activity of the carbon-doped TNTs in the dark and under UV illumination (λ = 354 nm). C-TNT (7:93) exhibited the highest glucose electro-oxidation activity under the dark and UV illumination compared to C-TNT (33:67) and TNT. The glucose electro-oxidation (GAEO) current density on C-TNT (7:93) improved significantly under UV illumination compared to glucose electro-oxidation activity obtained in the dark. C-TNT (7:93) enhanced glucose electro-oxidation activity and stability under UV illumination. This electrode production method is promising for the design of photocatalytic glucose fuel cells.