磷钨酸修饰活性炭载Pd催化剂的制备及对甲酸氧化的电催化性能

摘要

通过水浴浸泡制备了磷钨酸( PWA)修饰的活性炭( PWA/C)，再通过液相还原法将Pd沉积于PWA/C复合载体上制备了Pd-PWA/C催化剂。采用X射线能量色散( EDS)谱、X射线衍射( XRD)谱、透射电子显微镜( TEM)和X射线光电子能谱( XPS)对产物进行表征。结果表明，磷钨酸修饰活性炭不仅能有效降低Pd纳米粒子的粒径，而且与Pd纳米粒子间发生了强烈作用。电化学测试结果显示， Pd-PWA/C催化剂对甲酸氧化的电催化活性和稳定性均远优于Pd/C催化剂，这是由于Pd与PWA/C间的强烈作用既能有效降低CO在催化剂上的吸附强度和吸附量，又能降低甲酸分解的速率，从而减弱CO的毒化作用。%Activated carbon was modified with phosphotungstic acid( PWA) at 80 ℃ in a water bath, Pd was then loaded on the PWA/C hybrid support to prepare Pd-PWA/C catalyst by a simple impregnation-reduction method. The measurements of energy dispersive X-ray spectroscopy( EDS) , X-ray diffraction( XRD) pattern, transmission electron microscopy(TEM) and X-ray photoelectron spectroscopy(XPS) indicate that phospho-tungstic acid-modified carbon not only decreases the average size of Pd nanoparticles effectively but also interacts with Pd nanoparticles strongly. The electrochemical measurements demonstrate that the electrocataly-tic activity and stability of the Pd-PWA/C catalyst for formic acid oxidation are much better than that of the Pd/C catalyst. It is due to that the strong interaction between Pd and PWA/C not only decreases the adsorp-tion strength and amount of CO at the catalyst electrode but also decreases the decomposition rate of formic acid to decrease the CO poisoning.