【摘要】 采用纳米氧化铈(CeO2)改性磺化度48.3%的磺化聚醚醚酮(SPEEK),通过溶液浇铸法制备用于直接甲醇燃料电池的质子交换膜.在两种介质中测试改性膜的电导率均随温度的升高而增大,与未改性膜相比却大小正好相反:在1 mol/L以盐酸溶液为电解液的测试介质中,改性膜的电导率是未改性膜的15倍,在水蒸气测试介质中,却仅为40%.红外光谱分析表明,CeO2中的铈原子与—SO3H基团中的氧原子发生配位作用.X射线衍射仪(XRD)分析可见,当复合膜浸入1 mol/L盐酸4 h前后,纳米CeO2的晶体结构未见明显变化,表明所发生的配位作用仅处于CeO2和SPEEK两个固相界面上.扫描电子显微镜(SEM)观察改性膜和未改性膜均无网络结构和微相分离,质子在膜内通过—SO3H基团之间的跃迁传导,酸溶液介质远比水蒸气有利于质子在纳米CeO2改性SPEEK膜内磺酸基团之间的跃迁.更多还原

【Abstract】 The membranes of sulfonated polyether ether ketone(SPEEK) with the degree of sulfonation(DS) of 48.3%,doped with nanometer cerium oxide(CeO2) were prepared for direct methanol fuel cell application by solution casting technique.The proton conductivity of SPEEK/CeO2 composite membranes increased with the increasing of temperature and the contrary regular pattern occurred under the two testing media compared with pure SPEEK membrane.The conductivity of SPEEK/CeO2 composite membrane was 15 times higher than that of pure SPEEK membrane in testing medium with 1 mol/L hydrochloric acid as the electrolyte,but reduced to about 40% in the water vapour.Fourier transform infrared(FTIR) spectroscopy revealed a certain coordination existing between oxygen atom in —SO3H groups and cerium atom in the CeO2.X-ray diffraction(XRD) results demonstrate that,whether the SPEEK/CeO2 composite membrane or the composite membrane immersed with 1 mol/L hydrochloric acid for 4 h,the crystal structure of CeO2 in SPEEK/CeO2 composite membrane has no obvious change,which indicates that the coordination exists only in two solid-phase interfaces.Scanning electron microscopy(SEM) shows that modified/unmodified membranes has no net structure or microphase separation.Therefore,the proton can be transported through jumping between —SO3H groups in membranes.Acid solution is more advantageous to proton jumping between —SO3H groups in membranes than water vapour.更多还原