纳米Au粒子作为直接硼氢化钠-过氧化氢燃料电池阴极催化剂

Performance of Nanosized Au Particle as a Cathode Catalyst for Direct Borohydride-hydrogen Peroxide Fuel Cell

采用浸渍还原法制备了纳米Au/C,并将其用作直接硼氢化钠-过氧化氢燃料电池阴极催化剂.通过X射线衍射(XRD)和透射电镜(TEM)对催化剂进行结构和形貌分析,结果表明10～20nm的纳米Au粒子均匀地分散在VulcanXC-72R碳黑表面上.循环伏安测试表明,在0.5mol·L-1H2SO4和2mol·L-1H2O2混合溶液中,纳米Au/C在0.85V处表现较强的不可逆还原电流.以纳米Au/C为阴极催化剂,AB5储氢合金为阳极催化剂制成直接硼氢化钠-过氧化氢燃料电池.电池在30℃下的最大功率密度可达到78.6mW·cm-2.当电池工作温度升高至50℃时,电池的最大功率密度超过120mW·cm-2.此外,研究了阴极溶液中H2SO4和H2O2浓度对电池性能的影响.当阴极溶液中H2SO4浓度小于0.5mol·L-1时,酸浓度对电池性能影响较大;H2O2浓度对电池性能影响较小.确定了阴极溶液中H2SO4和H2O2的最佳浓度分别为0.5和2mol·L-1.

Nanosized Au particles were prepared as a cathode catalyst for the direct borohydride-hydrogen peroxide fuel cell （DBHFC） by impregnation methods. The structure and surface morphology of the carbon-supported gold catalyst （Au/C） were characterized by X-ray diffraction （XRD） and transmission electron microscopy （TEM）. It was found that 10～20 nm Au particles deposited on Vulcan XC-72R carbon black. The cyclic voltammogram （CV） results showed that the onset of reduction current on the Au/C occurred at 0.85 V in 0.5 mol·L^-1 H25O4 and 2 moloL 1 H2O2. Also, a simple DBHFC was presented in which the Au/C was used as the cathode catalyst and a hydrogen storage alloy as the anode catalyst. The maximum power density of 78.6 mW·cm^-2 was obtained at 30℃. When operated at 50 ℃, the DBHFC gave a higher than 120 mW·cm^-2 power density. Furthermore, the effect of H2SO4 and H2O2 concentrations on the per-formance of DBHFC was described. The results exhibited that the performance of DBHFC had a strong dependence on the acid concentrations when H2SO4 concentration was lower then 0.5 mol·L^-1, while the H2O2 concentrations had little influence on the performance of DBHFC. The results showed that the optimum concentrations of H2SO4 and H2O2 were 0.5 and 2 mol·L^-1, respectively.