Investigation On The Synthesis And Properties Of Non-Pt Catalysts For Direct Methanol Fuel Cell System

Now adays with the progress of human society, people have more in-depthunderstanding of.the energy and environmental issues, looking forward efficientgreen energy has becoming the core of the world’s energy development strategy.Direct methanol fuel cell (DMFC) technology becomes a hot point of researchand development due to its high theory efficiency, environmental friendly, andeasy to get fuel and so on. And it has widely used in automobiles, aircraft,aerospace, marine and other fields. But, in the practical application, large-scalepromotion of the use of fuel cells has been plagued by its high costs and the lowpractical energy conversion efficiency. The fundamental reason is that the priceof electricity the catalyst is expensive and inefficient under existing conditions;therefore it is imperative to develop a high catalytic activity of the catalystwhich price is relatively cheaper. This paper attempts to use other metals(palladium, silver) instead of platinum as catalyst, and using PVP Protectedmethod to make metals supported on a novel carbon material’s (Vulcan XC-72)surface, which increase the contact area per unit mass improve metal utilizationefficiency, more over lower utility costs.The first part to adopt XC-72as the carrier, synthetic Pd/C catalyst by thesol-gel method, varying the type of base (NaOH, ammonia), changing theamount of alkali added, changing the reducing agent (NaBH4) dose for filteringformula to make the optimal catalyst. The experimental samples were tested byelectrochemical measurements (CV), XRD, TEM characterization, and we alsotest the actual loading of palladium，from different point of views to compare thePd/C catalyst’s activity. The conclusion as follows, addition of a base increase the loading of palladium, and the weak base ammonia is better than the alkalihydroxide; and in the corresponding system,3ml ammonia as the best dosage.By testing also showed that the addition ammonia not only improves the loadingamount of the metal, but also improve the degree of dispersion and the particlesize. Which the metal catalyst’s particles made by3ml ammonia is smallest,most uniform dispersion.The second part, because the silver and palladium in the same period of theperiodic table and in the adjacent main group, they may have similarities witheach other. More important, silver compared with palladium has a great priceadvantage, so the study of Ag as anode catalyst is very necessary. In this studywe have added40times,80times,160times of sodium borohydride preparedAg/C catalyst, and test them with cyclic voltammetry (CV) and XRD, TEMcharacterization. Finally we test the actual loading of silver. The results showthat with the addition dose of reduction increases catalytic activity increasedgradually. The study also found that different amounts of reducing agents didnot affect the loading amount of the catalyst, which affects the size anddispersion of metal particles. The results show that under the conditions of160times of the sodium borohydride, which is the best drug dosage,system the Ag/Ccatalyst’s silver particles are uniformly dispersed better and it has highestelectro-catalytic activity. However, comparing the single metal palladiumcatalyst, the particles of silver are larger. And the using of silver is not veryefficiency.The third part, due to the results in first part and second part which the Agand Pd show different catalytic features if combination of the two advantages,the catalyst would more desirable than others. This part the Pd-Ag bimetalliccatalysts which supported by Vulcan XC-72with sol-gel method were studied.NaOH was added to adjust the pH and different amount of sodium borohydridewere added to control the crystal growth. Add40,60and160times of sodium borohydride respectively in three different electrochemical test sample and testthem by XRD, TEM and CV, finally calculate the actual loading percent. Theconclusion is that the catalyst with80times sodium borohydride shows the bestcatalytic activity.At the end of the article, a reasonable proposal for future research work ismade based on the problems and experience of the catalyst. The method ofpreparation of carbon supported catalyst in this paper whould have broadenapplicability.and have a profound impact on making other nano catalysts.