钒取代多金属氧酸盐/聚酰胺-胺多层膜的制备及其电催化性能

用层接层自组装的方法制备了过渡金属钒取代的多金属氧酸盐PMo11VO4-40/聚酰胺-胺多层纳米复合膜. X射线光电子能谱(XPS)、紫外-可见光谱(UV-Vis)、循环伏安(CV)测定和分析结果表明, PMo11VO4-40和聚酰胺-胺通过静电相互作用形成了纳米交替多层膜,且膜的增长均匀. 复合膜的循环伏安图呈现出四对氧化还原峰(一个V的单电子和三个Mo的双电子), 峰电流与扫描速率成正比, 其式量电位随着pH 的增加而线性负移, 表明电极过程属于表面控制过程, 电荷传递很快且有氢离子参与多金属氧酸盐的氧化还原反应. 该方法制备的多层膜修饰电极稳定性好, 对NO-2、BrO-3及H2O2具有良好的催化还原活性.

Preparation and Electrocatalytic Property of Multilayer Films Constructed from Vanadium Substituted Polyoxometalate and Poly(amidoamine)

The novel multilayer nano-composite films consisting of vanadium mono-substituted polyoxometalates (PMo11VO4-40) and a generation-4 poly(amidoamine) (PAMAM) dendrimer were fabricated on quartz and glassy carbon electrode substrates by layer-by-layer self-assembly technique. The incorporation of PMo11VO4-40 and PAMAM into the films was confirmed by XPS. The multilayer films were grew gradually and uniformly in the synthesis process as monitored by UV-Vis and cyclic voltammetry. Four pairs of redox peaks which corresponded to V5+/V4+ and Mo6+/Mo5+ were observed in the cyclic voltammogram of multilayer films. The dependence of peak current on scan rate was indicative of redox surface-confined species and the charge transfer was very quick. The formal potential of the composite films was shifted linearly to negative position at higher pH, which implied that the protons were involved in the redox processes of polyoxometalates. The multilayer films were stable and exhibited good catalytic activities for the reduction of NO-2 , BrO-3, and H2O2.