Direct Attachment of Glucose-Oxidase On Carbon Paper for Biofuel Cell Application

In this study, we directly immobilize glucose oxidase (GOx) onto the carbon paper using two different enzyme immobilization techniques: (1) Covalent Attachment (CA) and (2) Enzyme Precipitation and Crosslining (EPC). We use these carbon papers with immobilized GOx as the enzyme anode electrode for fabricating an airbreathing enzymatic biofuel cell (BFC). A total size of our biofuel cell is similar to a size of U.S. penny. Performances of biofuel cells are tested under the ambient operating conditions using 200 mM of glucose solution containing 10 mM benzoquinone (BQ). No buffer solutions are used for our study to mimic the real-world application. Under these operating conditions, our biofuel cell with CA and EPC enzyme anode electrodes can produce a maximum power density of 8.4 and 110 uW/cm2, respectively. From the constant voltage test of our biofuel cell with the EPC enzyme anode, it shows a stable current density output of > 700uA/cm2 at 0.18V over 45 hours. When the biofuel cell with the EPC enzyme anode operated with a real maple syrup under the ambient conditions, it produces a stable current density of >10 uA/cm2 at 0.18V over 25 hours.