요 약NaBH 4 가수 분해용 경량반응기의 재질로서 알루미늄 합금을 검토하였다. 알루미늄은 알칼리에 용해되는데, NaBH 4 반응 용액중에 안정화제로 NaOH가 포함되어 있다. 알루미늄의 부식 속도를 낮추기 위해서 NaOH 농도를 낮추면 저 장중에 NaBH 4 가 손실된다. 그래서 최적의 NaOH 농도를 결정할 때 알루미늄 부식과 NaBH 4 안정화를 모두 고려해야 한다. NaBH 4 안정화와 알루미늄 부식속도는 수소발생속도에 의해 측정하였다. Abstract − Aluminum alloy was examined as a material of low weight reactor for hydrolysis of NaBH 4. Aluminum is dissolved with alkali, but there is NaOH as a stabilizer in NaBH 4 solution. To decrease corrosion rate of aluminum, decrease NaOH concentration and this result in loss of NaBH 4 during storage of NaBH 4 solution. Therefore stability of NaBH 4 and corrosion of aluminum should be considered in determining the optimum NaOH concentration. NaBH 4 stability and corrosion rate of aluminum were measured by hydrogen evolution rate. NaBH 4 stability was tested at 20~50 o C and aluminum corrosion was measured at 60~90 o C. The optimum concentration of NaOH was 0.3 wt%, considering both NaBH 4 stability and aluminun corrosion.

− Until a recent day, degradation of PEMFC MEA(membrane and electrode assembly) has been studied, separated with membrane degradation and electrode degradation, respectively. But membrane and electrode were degraded coincidentally at real PEMFC operation condition. During simultaneous degradation, there was interaction between membrane degradation and electrode degradation. Hydrogen permeability was used often to measure degradation of electrolyte membrane in PEMFC. In case of hydrogen permeability measured by LSV(Linear Sweep Voltammetry) method, the degradation of electrode decrease the value of hydrogen crossover current due to LSV methode's dependence on electrode active area. In this study hydrogen permeability was measured by gas chromatograph(GC) when membrane and electrode degraded at the same time. It was showed that degradation of electrode did not affect the hydrogen permeability measured by GC because of GC methode's independence on electrode active area.

− Proton Exchange Membrane Fuel Cells (PEMFC) can generate hydrogen and oxygen from water by electrolysis. But the electrode and polymer electrolyte membrane degrade rapidly during PEM water electrolysis because of high operation voltage over 1.7V. In order to reduce the rate of anode electrode degradation, unsupported IrO 2 catalyst was used generally. In this study, Pt/C catalyst for PEMFC was used as a water electrolysis catalyst, and then the degradation of catalyst and membrane were analysed. After water electrolysis reaction in the voltage range from 1.8V to 2.0V, I-V curves, impedance spectra, cyclic voltammograms and linear sweep voltammetry (LSV) were measured at PEMFC operation condition. The degradation rate of electrode and membrane increased as the voltage of water electrolysis increased. The hydrogen yield was 88 % during water electrolysis for 1 min at 2.0V, the performance at 0.6V decreased to 49% due to degradation of membrane and electrode assembly.

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− During start up and shut down of a proton exchange membrane fuel cells (PEMFC), the performance and lifetime of PEMFC were reduced. In this study, effect of startup and shutdown were investigated in dead-end type PEMFC using oxygen as a cathode gas with polarization curve, impedance spectroscopy (EIS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Dummy load which eliminates residual hydrogen and oxygen during startup and shutdown operation should be applied to mitigated the degradation of PEMFC performance. At 50% relative humidity (RH) under the repetitive on/off cycling, the cell performance decayed faster than at 100% RH because of corrosion of the cathode carbon support. Water suppling into cell reduced the degradation rate of dead-end type PEMFC during start up and shut down cycling at 50% RH.