Electroreduction of O-2 to water on the "Wired" laccase cathode

Oxygen was electrocatalytically reduced to water at a current density of 5 mA/cm(2) and at +0.7 V (NHE) in pH 5 citrate buffer at 37.5 degreesC. The e lectrocatalyst was a composite of laccase cross-linked with a redox. polyme r on a hydrophilic cloth of 10 Aim diameter carbon fibers. The redox polyme r, PVI-Os(tpy)(dme-bpy)(2+/3+), [poly-N-vinyl imidazole with 1/5(th) of the imidazoles complexed with [Os(tpy)(dme-bpy)]2+/3+ (tpy=terpyridine; dme-bp y= 4,4'-dimethyl-2,2'-bipyridine)], electrically connected ("wired") the la ccase reaction centers to the fibers.