氢气泡制备枝晶状多孔钯银薄膜及其催化性能

Hydrogen bubble templated co-deposition of dendritic porous PdAg films and electrocatalytic activity

摘要:

通过氢气泡动态模板法制备了具有多孔枝晶壁的钯银合金薄膜，微米级的大孔和枝晶间的间隙提供了反应过程中的介质传输通道。调节硝酸钯和硝酸银的配比制备了不同成分的钯银合金薄膜且研究了银的添加对催化性能的影响。循环伏安（CV）曲线表明钯银合金具有高的催化活性且银的添加可提高单位质量钯的催化活性，其中多孔Pd51Ag49的催化电流密度为0.49 A/mg，是多孔钯的1.47倍。X射线光电子能谱（XPS）结果说明钯银薄膜催化活性的提高可归因于钯银合金形成时银原子进入钯晶格间隙引起的钯电子结构的改变，X射线衍射（XRD）谱图和元素面扫（EM）结果也说明了合金的形成。

Abstract:

PdAg films with self-supported porous dendritic walls were fabricated by hydrogen dynamic template method, which could provide as the transport channel due to the micron-sized pores and the interstices between the dendrites. Different composition PdAg catalysts were obtained by adjusting the proportion of Pd(NO₃)₂ and AgNO₃ and it was also studied that the effect of the addition of Ag on the catalytic performance for ethanol. The cyclic voltammetry (CV) curves showed that PdAg films possessed high catalytic activity for ethanol and the addition of Ag significantly increased the mass-normalized catalytic activity of Pd. The mass-normalized catalytic current density of porous Pd₅₁Ag₄₉ is 0.49 A/mg, and it was estimated as 1.47 times as porous Pd. X-ray photoelectron spectroscopy (XPS) study indicated that the enhancement of the catalytic activity of PdAg films could be ascribed to the change of the Pd electronic structure when Ag atoms are embedded into the Pd lattice to form PdAg alloy as shown in X-ray diffraction(XRD) and element analysis mapping (EM) results.