Fabrication of palladium nanowire array electrode for biofuel cell application

Bioelectrocatalysis was demonstrated with palladium (Pd) nanowire array electrode via nonenzymatic and enzymatic methods for glucose, which was validated by the generation of anodic current in the presence of glucose. The vertically standing Pd nanowires used for the fabrication of the electrodes were on average 5.6 mu m in length and 64 run in diameter. In comparison, the nonenzymatic bioanode exhibited lower current densities and required the application of larger overpotential which resulted in a large cell voltage drop (V-oc = 13.5 mV) and limited power production when assembled as a biofuel cell under physiological conditions (pH 7, 0.1 M phosphate buffer saline) with laccase covalently bounded to Pd nanowires as the biocathode. The glucose/O-2 biofuel cell was studied in phosphate buffer saline using the enzymatic bioanode that was developed with the co-immobilization of catalase and glucose oxidase on Pd nanowires and the laccase-Pd as the biocathode. The biofuel cell exhibited an open-circuit voltage of 0.506 V, delivered a maximum power density of 72 mu W cm(-2) at a cell voltage of 0.25 V and a short-circuit current density of 411 mu A cm(-2) when operating in 10 mM glucose. Such low-cost lightweight glucose/O-2 biofuel cells have a great promise to be optimized, miniaturized to power bio-implantable devices. (C) 2015 Elsevier B.V. All rights reserved.