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

Preparation of Phosphotungstic Acid-modified Carbon Supported Pd Catalyst and Its Electrocatalytic Performance for Formic Acid Oxidation

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 ~C 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- tungstie acid-modified carbon not only decreases the average size of Pd nanopartieles 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.