Pdn-Fe纳米合金作为Mg-H2O2半燃料电池阴极研究

通过化学还原方法制备Pd:Fe原子比(n)为2 : 1、4 : 1、8 : 1的Pd_n-Fe/C催化剂。采用TEM、XRD和XPS技术对复合催化剂进行表征。结果显示, Fe加入Pd/C催化剂中, 与Pd形成合金, Pd_n-Fe/C催化剂的粒径发生变化; 获得的Pd₄-Fe纳米合金粒子在C载体表面分布均匀, 平均粒径为2~3 nm, Fe的加入对Pd/C催化剂晶体结构有很大影响。电化学(CV, LSV, CA)测试表明: 加入Fe提高了Pd/C催化剂的催化性能, Pd/Fe原子比为4 : 1时, Pd_n-Fe/C的催化性能最好。当E=0.2 V时, Pd/C电极电流密度为17.71 mA/cm², 而Pd₄-Fe/C电极电流密度可达19.42 mA/cm²。电池测试表明, 以Pd₄-Fe/C和Pd/C催化剂为阴极的Mg-H₂O₂半燃料电池的开路电势均为1.8 V左右, 而当电流密度为180 mA/cm²时, 以Pd₄-Fe/C为阴极的电池最大能量密度比Pd/C为阴极的电池高41 mW/cm²。

Cathode Performance of Mg-H2O2 Semi-fuel Cell with Pdn-Fe Alloy as Cathode

Carbon-supported palladium-iron composite electrocatalysts with different Pd to Fe atom ratios (2 : 1, 4 : 1, 8 : 1) were prepared by a chemical reduction method. The morphology and surface state of the Pd_n-Fe/C and Pd/C electrocatalysts were characterized by X-ray diffractionanalysis (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The results indicated that Fe was added to the Pd/C catalyst and reacted with Pd to form Pd_n-Fe alloy, with slightly varied particle size. And the Pd_n-Fe catalyst particles were homogeneously distributed on the surface of the C carrier with the average particle size between 2-3 nm. The addition of Fe influenced crystal lattice structure of Pd/C catalysts. Electrochemical (CV, LSV, CA) data showed that the eletrocatalytic activity of the Pd₄-Fe/C electrocatalyst for hydrogen peroxide electroreduction was much higher than that of Pd/C. The current density of Pd/C electrode for hydrogen peroxide electroreduction reaction was 17.71 mA/cm² when E = 0.2 V and the current density of Pd₄-Fe/C electrode was up to 19.42 mA/cm². The Mg-H₂O₂ semi-fuel cell performance text showed that both the open circuit potential of the two fuel cells were about 1.8 V, of which the power density of Mg-H₂O₂ semi-fuel cell using Pd_n-Fe/C as the cathode was higher 41 mW/cm² than that using Pd/C as cathode.