Effect of Palladium Ratio on the Performance of Direct Formic Acid Microfluidic Fuel Cells
Jin-Cherng Shyu, Po-Yen Wang and Ke-Wei Cheng
The effects of Pd/C ratio on both the performance of air-breathing direct formic acid microfluidic fuel cells and the bubble pattern on the cells anode surface were investigated. The anode containing palladium and Nafion of 10 mg/cm2 and 6 mg/cm2 , respectively, was self-made with Pd/C ratios of 75%, 85%, and 95%. 0.3-M, 0.5-M and 1.0-M HCOOH mixed with 0.5-M H2SO4 was used as the fuel supplied at a flow rate of 0.5 mL/min. The results showed that the cell having a 75%-Pd/C anode had numerous deep cracks on the electrode surface and caused the CO2 bubbles to be trapped on the electrode, while the cell having an 85%-Pd/C anode allowed the bubbles to periodically generate and detach from the electrode surface. The peak power density of the fuel cell fed with 0.5-M HCOOH was 22, 30 and 27 mW/cm2 for cells of 75%, 85% and 95% Pd/C ratio, respectively.
Keywords: Microfluidic, formic acid, fuel cells, air-breathing, bubbles, Pd/C ratio