Preparation Of New Type Alcohol Oxidation And Oxygen Reduction Electric Catalyst

At present, the world is facing serious environmental pollution and energy shortages, itmakes the clean and environmentally friendly fuel cells become a research hotspot. Due the fuelcell has a simple structure, easy to store and carry fuel, theoretical high energy density and othercharacteristics, so that in the field of power has good application prospects.Proton exchange membrance fuel cells (PEMFC) compared with conventional fuel cells,have high energy conversion rate, no pollution, ample fuel sources, conveniently of storage andtransportation advantages etc. It belongs to the green energy technology, directly to madechemical energy of fuel converted into electrical energy through the electrochemical methods. Theperformance of catalyst for PEMFC, service life and stability plays a vital role. But remarkably,anode and cathode catalysts still is given priority to with platinum and other noble metals, thisgreatly increased the cost of the PEMFC, thus limiting its wide application. Therefore, reduce theamount of precious metal catalyst, again in the based on reducing the amount of platinum, toresearch the non-precious metal catalysts, it is the effective way to reduce the cost of fuel cell.Aim of the alcohol oxidation and oxygen reduction is to release electron, then generateelectric current, thereby providing power to the load. To make these two processes are more proneto happen, and release more electron, focus lies in the choice of catalysts. So in this paper, wecommenced from to reduce the cost of catalyst preparation, as well as to improve the catalyticactivity, select more widely study which was PtSn/C, Pd/C, heteropolyacids, transition metal andmacrocycles as raw material, to synthesize the green and high activity catalyst, the main researchin the following aspects:(1) This article from the current study good binary catalyst PtSn/C proceed, the ternarycatalyst PtSn/C was synthesised by an ethylene glycol reduction method (EG method). UsingX-ray diffraction (XRD) and electrochemical performance test characterization methods, todetermine the composition and properties of the catalysts, and and calculate the electrochemicalactive surface area (ECSA) The experimental results show that the addition of Fe reduce of metalcatalyst particle size, comparing with the Pt/C, PtSn/C, PtFe/C catalyst, PtSnFe/C catalyst hashigher ECSA and better catalytic activity for ethanol oxidation reaction.(2) In this paper, we use the carbon carrier, which modified by polyaniline (PAN), toimmobilizing phosphomolybdic acid (HPMo). The obtained HPMo-PAN-C sample is used as thesupport to prepare a Pd/HPMo-PAN-C catalyst. The samples are characterized by fouriertransform infrared spectroscopy, transmission electron microscopy and X-ray diffraction analysis.The results suggest that HPMo retains its Keggin structure and that the presence of HPMo reducesthe average particle size of the Pd nano-particles in the obtained Pd/HPMo-PAN-C catalyst. Electro-chemical measurements in0.5M HClO4solution reveal that the Pd/HPMo-PAN-Ccatalyst has higher catalytic activity for oxygen reduction reactions than does a Pd/C catalystprepared using a similar procedure. The stability of the Pd/HPMo-PAN-C catalyst is evaluated bymultiple-cycle voltammetry techniques; the mass catalytic activity decreases by only10%after100scanning cycles.(3) This article uses the transition metal iron to prepare the non-noble metal catalysts. We usetwo different atmospheres to obtain Fe3O4-PPy/C and Fe-PPy/C catalyst through heat treatment,focuses discussed on the affect of transition metal iron to these two catalysts for oxygen reductionreaction (ORR). Through the X-ray diffraction spectrum (XRD) characterization, the results showthat the catalyst present in these two different forms of iron, one is Fe3O4, the other is elemental Fe.By rotating disk electrode (RDE) test, the results show that, Fe3O4-PPy/C catalyst activity washigher than Fe-PPy/C catalyst. There was no change before and after leaching in the chemicalactivity of the catalyst, it shows that, in ORR process, a transition metal iron in the catalyst doesnot provide active sites.