Raney-platinum thin film electrodes for the catalysis of glucose in abiotically catalyzed micro-glucose fuel cells

Abstract

Fuel cells capable of synthetic glucose catalysis have revolved around the implementation of abiotic catalysts that require extreme acid and alkaline environments. These are not compatible with implantable medical sensor systems, and hence, there is a need to develop abiotic catalysts that operate at neutral pH. This paper presents structural and electrochemical characteristics of a nanoporous electrode designed for abiotic glucose oxidation in the presence of oxygen in neutral physiological media. The electrode was fabricated by annealing e-beam deposited thin films of platinum (Pt) and nickel (Ni) into a Pt–Ni alloy on a silicon substrate. The porous nature of the alloy enhances electrochemical properties by increasing the real surface area ~ 500 times compared to the geometric surface area of as-prepared multilayer thin films. This was reflected in the exchange current density of the electrode annealed at 800 °C being twice that of the electrode annealed at 650 °C. The cell voltage increase, due to the addition of dissolved physiological oxygen of 2 ppm, was about 100 ± 8 mV under a load current density of 2 µA cm−2. After running for 72 h in a physiological saline solution with 5 mM glucose, the increase in the electrode potential was only 23 µV h−1. These results suggest that the nanoporous Pt–Ni alloy anode offers an improved catalytic stability with time and should be a viable candidate for use in abiotic catalyzed glucose fuel cell systems operating under physiological conditions.