A Wired Laccase Oxygen Cathode with Carboxylated Single‐Walled Carbon Nanotubes Incorporated

The wired laccase cathode with the incorporation of single‐walled carbon nanotubes (SWNTs) functionalized with carboxyl groups was constructed. As the wiring redox polymer, the copolymer of polyacrylamide and poly( N ‐vinylimidazole) complexed with [Os(2,2′;6′2″‐terpyridine)(4,4′‐dimethyl‐2,2′‐bipyridine)] 2+/3+ (PAA‐PVI‐[Os(tpy)(dme‐bpy) 2 ] 2+/3+ ) was used. The prepared laccase cathode was applied for the electrocatalytic reduction of oxygen. With the addition of the carboxylated carbon nanotubes (CNT‐COOHs), in comparison to the result with no CNT‐COOHs included, the catalytic O 2 reduction current density increased from 0.35 mA/cm 2 to 0.59 mA/cm 2 at the cathode under the condition of a 500 rpm electrode rotation speed in an air‐saturated pH 5.0 2.0 M citrate buffer at 37°C. Other effects showing less current decreases with halide ion additions and enhanced stability, when CNT‐COOHs were included, were also observed.