A Visual Study of Bubble Formation in Microfluidic Fuel Cells

摘要

Two microfluidic fuel cells having microchannel widths of 1.0 mm (cell #1) and 0.5 mm (cell #2) with electrode spacing of 0.4 mm were tested at volumetric flow rates ranging from 0.1 to 1.0 ml min-1. The concentration of hydrogen peroxide was tested at 0.1, 0.3, and 0.6 M. An additional microfluidic fuel cell (cell #3) having microchannel width of 0.5 mm and electrode spacing of 0.2 mm was also tested. Bubble formation under various tested conditions in different microchannels are presented. The open circuit voltage of the cells increased as reactant volumetric flow rate increased. Effect of electrode spacing on cell performance depends on the reactant concentration and volumetric flow rate. Also reported was the area-specific internal resistance of the present cells and their fuel utilization corresponding to peak power density at a given flow rate with [H_2O_2] = 0.1 M. For cell #1, cell #2, and cell #3, respectively, the maximum power densities were 9, 40, and 16 mW cm~(-2) at 1.0 ml min~(-1) and 0.6 M, while the maximum power densities were 5, 11, and 15 mW cm~(-2) at 1.0 ml min~(-1) and 0.1 M.