Direct Ethanol Membraneless Nanofluidic Fuel Cell With High Performance

An air‐breathing nanofluidic fuel cell (AB‐NFC) was evaluated using ethanol as the fuel. Two Pd electrocatalysts, one commercial (ETEK) and one synthesized (Pd IL), were tested as anodes and using carbon nanofoam as three‐dimensional flow‐through electrodes. It was found from the polarization and power density curves that despite differences in particle sizes, both of the electrocatalysts exhibited similar power densities in an alkaline AB‐NFC (15.4 to 15.8 mW cm−2). Nevertheless, the Pd IL provided stability over time to the AB‐NFC while performing at a higher ethanol concentration (1.5 M), which was related to its greater tolerance to poisoning compared to the commercial Pd. The cell performance of the AB‐NFC was enhanced by changing the pH of the cathodic electrolyte from an alkaline to an acidic pH. The net cell efficiency increased 44 % with a power density near 100 mW cm−2, which is one of the best power densities reported to date for membraneless micro/nanofluidic fuel cells. A nanofluidic fuel cell is developed and evaluated employing ethanol as fuel and Pd/C synthesized through a green method as anode. The resulting net cell efficiency was 44 % with a power density of 100 mW cm−2. This device supplies a constant maximum current density of 125 mA cm−2 through time, being 5‐fold higher than the current provided using commercial Pd/C ETEK.