| Popis: |
Proton exchange membrane fuel cells (PEMFC), which are promising eco-friendly energy sources, need to operate under low humidity conditions in order to be applied for small electrical devices. In such low relative humidity condition, hydration of membrane electrode assembly in the fuel cell system is an important key to prevent performance degradation due to decreased ion conductivity of the Nafion® membrane. Herein, amorphous carbon capsuled carbon nano-onions (AC-CNO) were prepared by irradiating a laser to gaseous hydrocarbons flame capable of mass continuous production. The particles have high-quality graphitic layers in the form of spherical multi-shelled fullerenes and the outermost layer is surrounded by oxygen functionalized amorphous carbon. The particles of various sizes with the same morphology can be produced, and the hydrophilicity of particles with different sizes varies due to the structural characteristics in the catalyst layer and the amount of -OH functional groups attached to the amorphous carbon. The Pt/AC-CNO-3 catalyst layer made of AC-CNO with an average size of ~170nm was deposited on the anode electrode and the membrane electrode assembly (MEA) shows the best performance under low humidity, compared to MEAs with commercial Pt/C deposition; the current density reached 1200mA/cm2 at 0.6V and maximum power density reached 1080mW/cm2 with operating at 50% RH, 80℃ cell temperature under 1.8bar back pressure, while 870mW/cm2 in case of commercial catalyst Pt/C. |
