PtRu-SiO_2-TiO_2/C anode electrocatalyst for direct methanol fuel cell

摘要

The PtRu-SiO_2-TiO_2/C anode electrocatalyst (loading 10wt% PtRu) of direct methanol fuel cell is prepared by the surface reductive deposition method, using Vulcan XC-72 carbon black coated with nanometer SiO_2-TiO_2 (SiO_2-TiO_2/C) as the isotopic carrier. The surface characteristics of nanometer SiO_2-TiO_2 is studied through nitrogen adsorption, which shows that it is of porous structure together with large surface area, that is benefit to enhance the activity of SiO_2-TiO_2 and the dispersion of PtRu nanoparticle on the carrier of SiO_2-TiO_2/C. X-ray diffraction(XRD) and transmission electron microscopy(TEM) are used to characterize the catalyst. The PtRu nanoparticle homodisperse in SiO_2-TiO_2/C carrier with diameter around 2.4 nm. Cyclic voltammograms and chronoamperograms are conducted to compare the electrochemical methanol oxidation activity of the PtRu-SiO_2-TiO_2/C catalyst with the commercial PuRu/C catalyst (20 wt% of PtRu). The results show that PtRu-SiO_2-TiO_2/C has higher catalytic activity and anti-poisoning ability for methanol oxidation, the addition of porous SiO_2-TiO_2 can replace the PtRu to some extent, comparing with the commercial PuRu/C catalyst, not only the loading of PtRu has been cut down 50%, but also the electro-oxidizing activity of methanol improved. The electro-oxidizing mechanism is basically analyzed.