Effect of the protection layer formed by cross-linked gelatin on the stability and performance of glucose and oxygen fuel cells

A glucose oxidation catalyst comprising carbon nanotube, tetrathiafulvalene (TTF), gelatin, glutaraldehyde (GA) and glucose oxidase (GOx) (CNT/[TTF-GOx]/Gelatin + GA) is suggested to enhance the reactivity of glucose oxidation reaction (GOR), and the performance and stability of enzymatic biofuel cells (EBCs) using this catalyst. In this catalyst, TTF is used as mediator to transfer electron effectively, while GA is crosslinked to gelatin to form non-soluble network. The structure prevents the dissolution of gelatin from aqueous electrolyte and reduces the leaching-out of GOx and TTF molecules. To confirm the crosslinking effect of GA and gelatin, Fourier-transform infrared spectroscopy (FT-IR) and electrochemical evaluations are utilized. According to FT-IR analysis, it was observed that the amide I peak shifted after crosslinking. This is evidence showing the appropriate network formation and the reactivity of CNT/[TTF-GOx]/Gelatin + GA is well preserved even after multiple potential cycling. In addition, its GOx activity is regularly monitored for one month and the measurements prove that the structure prevents the leaching out of GOx molecules. Based on that, EBC using the anodic catalyst shows excellent performances, such as open circuit voltage of 0.75 V and maximum power density of 184 μW/cm².