A Paper-Based Microfluidic Fuel Cell Using Soft Drinks as a Renewable Energy Source

The research aims were to construct an air-breathing paper-based microfluidic fuel cell (paper-based <mml:semantics>mu</mml:semantics>FC) and to evaluated it with different soft drinks to provide energy for their prospective use in portable devices as an emergency power source. First, in a half-cell configuration, cyclic voltammetry showed that glucose, maltose, and fructose had specific oxidation zones in the presence of platinum-ruthenium on carbon (PtRu/C) when they were individual. Still, when they were mixed, glucose was observed to be oxidized to a greater extent than fructose and maltose. After, when a paper-based <mml:semantics>mu</mml:semantics>FC was constructed, PtRu/C and platinum on carbon (Pt/C) were used as anode and cathode, the performance of this <mml:semantics>mu</mml:semantics>FC was mostly influenced by the concentration of glucose present in each soft drink, obtaining maximum power densities at room temperature of 0.061, 0.063, 0.060, and 0.073 mW cm<mml:semantics>-2</mml:semantics> for Coca Cola<mml:semantics>(R)</mml:semantics>, Pepsi<mml:semantics>(R)</mml:semantics>, Dr. Pepper<mml:semantics>(R)</mml:semantics>, and 7up<mml:semantics>(R)</mml:semantics>, respectively. Interestingly, when the soft drinks were cooled, the performance was increased up to 85%. Furthermore, a four-cell stack <mml:semantics>mu</mml:semantics>FC was constructed to demonstrate its usefulness as a possible power supply, obtaining a power density of 0.4 mW cm<mml:semantics>-2</mml:semantics>, using Coca Cola<mml:semantics>(R)</mml:semantics> as fuel and air as oxidant. Together, the results of the present study indicate an alternative application of an <mml:semantics>mu</mml:semantics>FC using soft drinks as a backup source of energy in emergencies.