高活性的PtRu/C抗CO催化剂

PtRu/C——a CO-tolerance electrocatalyst with high activity

采用共沉积还原法制备了高分散度的催化剂PtRu/C。对此催化剂进行的XRD晶相分析表明 ,PtRu/C中的双金属形成了合金 ,并具有较高的分散度。通过EMFC中单电池的伏安曲线和循环伏安法考察了自制PtRu/C催化剂的活性 ,并与Pt/C和Johnson Matthey公司的PtRu/C进行了比较。由循环伏安中氢的氧化脱附峰的面积和电池纯氢燃料的性能 ,得到催化剂对H2 的活性顺序是 :Pt/C >自制的PtRu/C >Johnson MattheyPtRu/C ,而对H2 / (5× 10 -5)CO燃料的活性顺序是 :自制的PtRu/C >Johnson MattheyPtRu/C >Pt/C。通过对循环伏安中CO氧化过程的研究认为 ,CO的氧化通过双功能机理 (Bifunctionalmechanism)进行 ,Ru的加入提高了催化剂对H2 O的活性 ,使PtRu表面容易形成吸附态的含氧物种 (OH ) ads,从而降低了催化剂氧化CO的电势。

The PtRu/C catalyst with high disperison was prepared by means of co precipitation reduction method. The XRD analysis of crystal phase shows that the bimetal in PtRu/C forms alloy with high dispersion. The activity of homemade PtRu/C was tested by cyclic voltammetry and was compared with the PtRu/C made by Johonson Matthey company. According to the area of hydrogen stripping peak in cyclic votammetry and the performance of pure hyrdogen fuel in fuel cell, the activity of catalysts to H 2 is sorted as Pt/C>homemade PtRu/C>Johnson Matthey PtRu/C, while the performance of catalysts for the cell with H 2/(5×10 -5 ) CO as fuel is sorted as Pt/C>homemade PtRu/C>Johnson Matthey PtRu/C. The results of cyclic voltammetry show that the oxidation of CO proceed based on the bifunctional mechanism. The activity of catalyst to water is improved by the addition of Ru, which causes the forming of absorptive (OH) ads on PtRu surface, so the potential of catalyst for the electroxidation of CO is decreased.