TEMPO-Modified Linear Poly(ethylenimine) for Immobilization-Enhanced Electrocatalytic Oxidation of Alcohols

We demonstrate a method to simultaneously immobilize the oxidation catalyst, TEMPO, while dramatically enhancing its electrocatalytic activity toward several biologically available alcohols. TEMPO is covalently immobilized onto linear poly(ethylenimine), which is then cross-linked onto the surface of a glassy carbon electrode to form a hydrogel through which substrates can readily diffuse. The TEMPO-LPEI electrode is used as an anode capable of generating currents from 0.41 +/- 0.06 mA cm(-2) in the presence of 250 mM sucrose to 8.20 +/- 0.04 mA cm(-2) in the presence of 2 M methanol and 33.4 +/- 9.4 mA cm(-2) in the presence of 500 mM formate under neutral pH and at 25 degrees C. The newly described anode is combined with an enzymatic biocathode to construct a hybrid biofuel cell to produce 0.38 +/- 0.04 mA cm(-2) while using 2 M methanol as a fuel source.