Catalysts prepared from the carbon black impregnated with manganous nitrate solution and then heated at temperature from 270℃ to 450℃ were investigated. It was found that the impregnated catalysts heated at temperature of 340℃ exhibited the best catalytic activity for oxygen reduction in alkaline electrolyte. It was also found that the XRD spectra of pyrolytic MnO from manganous nitrate over 2340℃ were different from those below 340℃. The enhanced catalysis of air electrodes was ascribed to the formation of MnO crystal 2 with d-value of 2.72 A as the impregnated-catalysts was heated at temperature of 340℃. The other factors in preparation of air electrodes were also discussed.

This research aims to increase the utilization of platinum-ruthenium alloy (PtRu) catalysts and thus to lower the catalyst loadings in the electrode for methanol electrooxidation. The electrodeposition of PtRu was performed on a rotating disk electrode (RDE) of glassy carbon (GC), on which a layer of Nafion®-bonded carbon (Vulcan XC 72R) was dispersed in advance. First, the behavior of Pt RDE and GC RDE in an aqueous solution containing HCl, H2PtCl6 and RuCl3 was studied. It was found that the hydrogen evolution becomes a dominant reaction when the electrode potential is below -0.20 V vs. SSCE (saturated-potassium-chloride silver chloride electrode). The hydrogen evolution was strongly enhanced with the formation of nanometer-sized Pt particles on the RDE. To enrich Pt and Ru ions, present in the form of anionic complexes in solution, onto the carbon particles in the uncatalyzed carbon electrode (UCE) and, most importantly, to eliminate the hydrogen bubbles formed on the UCE during the cathodic deposition, a positive current was imposed on the UCE for a period of time prior to each step of cathodic deposition of PtRu, should multiple steps of cathodic deposition be required. Cyclic voltammograms (CVs) of electrodes in 0.5 M H2SO4 before and after deposition were used to evaluate the loading of metal catalysts based upon the profile of CV in a wide range of potentials from -0.20 to 1.1 V vs. SSCE. The catalytic activity of electrodes prepared under different conditions for methanol electrooxidation was studied by electrochemical methods. The results showed that the performance of the electrode (prepared in this study) with loadings estimated to 77 lg PtRu/cm2 is much better than that of a conventional electrode with loadings of 100 lg Pt/cm2. The role of ruthenium in methanol oxidation was also discussed in electrochemical terms.

Catalysts prepared from a mixture of Mn3O4 powders and carbon blacks carrying pyrolytic MnO2 were investigated for catalysis of oxygen reduction. It was found that the introduction of Mn3O4 to the pyrolysis process of manganous nitrate carried out on carbon blacks improved the performance of air electrodes as the amount of Mn3O4 was controlled within 15 wt % relative to the weight of carbon carrier. The mechanism of this improved behaviour was also investigated using X-ray diffraction (XRD). The results showed that Mn3O4 induced the formation of favourable MnO2 crystalline grains during the pyrolysis of manganous nitrate. The induced effect and the blocking effect of Mn3O4 on the catalysis of air electrodes catalysed by pyrolytic MnO2 were demonstrated both on carbon black and porous carbon carriers.

The effect of the addition of CeO2 to Pt/C catalysts on electrochemical oxidation of alcohols (methanol, ethanol, glycerol, ethylene glycol) was studied in alkaline solution. The ratios of Pt to CeO2 in the catalysts were optimised to give the better performance. The electrochemical measurements revealed that the addition of CeO2 into Pt-CeO2/C catalysts could significantly improve the electrode performance for alcohols oxidation, in terms of the reaction activity and the poisoning resistance, due to the synergistic effect. The electrode with the weight ratio of Pt to CeO2 equals 1.3:1 with platinum loading of 0.30mg/cm2 showed the highest catalytic activity for oxidation of ethanol, glycerol and ethylene glycol.

The research aims to increase the utilization of platinum (Pt) catalysts and thus to lower the catalyst loadings in the electrode for oxygen reduction reaction (ORR). The electrodeposition of Pt was performed on a rotation disk electrode (RDE) of glass carbon (GC), on which a layer of Nafion-bonded carbon of Vulcan XC 72R was dispersed in advance. The behaviors of Pt RDE and GC RDE in an aqueous solution containing HCl and H2PtCl6 were firstly studied. It was found that Pt deposition could be achieved if the electrode potential is controlled below −0.20V versus (saturated-potassium-chloride silver chloride electrode) SSCE. However, quite a high overpotential is necessary if a quick and apparent deposition were required. Unfortunately, at a high overpotential, the hydrogen evolution would be unavoidable and even accelerated by the formation of nanometer size of Pt particles on the RDE. It was found that it is futile to increase platinum deposits just through extending the deposition time. It was also found that too large deposition current is not helpful for increase of platinum deposition because most of the current was consumed on hydrogen evolution in this case. It has been confirmed that it is conducive to richen Pt ions, present in the form of anionic complex in solution, onto the working electrode to be deposited. It is also helpful to eliminate the hydrogen bubbles formed on the working electrode, i.e., uncatalyzed carbon electrode (UCE), by imposing a positive current on the UCE for a length of time in advance of each cathodic deposition. The potential changes during deposition were recorded. Cyclic voltammograms (CV) of electrodes in 0.5M H2SO4 before and after the deposition were used to assess loading of metal catalysts in a wide range of potential from −0.20 to 1.1V versus SSCE. The results have shown that the performance of such an electrode with loadings estimated to be 50μg Pt/cm2 is much better than those of a conventional electrode with loadings of 100μg Pt/cm2.

The oxygen reduction reaction (orr) on carbon-supported Pt and Pt3Fe alloy has been studied by means of the ab initio and density function theory approaches. A model cluster consisting of substrate carbon atoms, Pt and/or Fe atoms on the three major crystal planes (100), (110) and (111) of Pt and Pt3Fe, was applied to simulate the carbon-supported-catalyst behavior. The anchor effect of iron to platinum on carbon has been confirmed from quantum chemistry. The enhanced catalysis effect of Fe in Pt/Fe ally catalyst on the orr has also been confirmed by the evidence disclosed in analysis of the frontal molecular orbital energy and the change of the O/O bond.

在欠电位沉积（UPD）锡修饰的铂电极（UPD-sn/n）上，对甲醇电化学催化氧化过程进行了研究发现当Pt表面 UPD-sn的覆盖率在20%附近时，对甲醇的催化氧化的增强作用最为明显；在电位低于0.35v（vs RHE）时，甲醇在Pt与UPD-sn/Pt电极上氧化只进行到脱氢生成CO的步骤：在0.35v以后、表面sn-OH形成、反应sn-OH+COads=Sn+CO2+H++e有利于表面CO的去除：而Pt电极上、只有0.6v以后、才有反应Pt-OH+COads=Sn+CO2+H++e发生因此，Sn的存在有利于甲醇在较低的电位下氧化：Pt电极上CH3OH脱氢并释放出电子的过程是一个快速的过程、表面CO的去除是甲醇氧化过程的控制步骤：甲醇氧化产生的表面吸附态CO以线式吸附为主、少量的桥式吸附态CO在反应初期即达到吸附饱和：Pt表面上upd-sn表现的催化增强作用、在光亮铂电极和在高分散铂黑电极上是一致的

A model of the air electrode used in fuel cells was developed which accounts for the diffusion of oxygen in the gas-filled pores as well as diffusion into the liquid-filled pores, and electrochemical reaction. The model was applied to the air electrode in the phosphoric acid fuel cell (PAFC) to simulate the cathode performance under a variety of conditions. Two parameters AB and AI were introduced into the model. They reflect, respectively, the effects of the interfacial surface area between the gas and liquid phases and those of the interfacial surface area between the liquid and solid phases, on the air electrode performance. AB and AI can be determined with the aid of the operating conditions and potential current density curves of the air electrode. The main interface parameters of the air electrode can be predicted following the determination of AB and AL The reaction rate throughout the catalyst layer was calculated by means of the model.

Platinum and platinum-tin alloy dispersed on active carbon are used as the catalysts for methanol clcctro-oxidation. Gas chromatographic and X-ray powder diffraction analysis show that the co-existence of Pt/C and PtSn/C in the catalysts yields better catalysis for methanol clcctro-oxidation than Pt/C alone. The electrochemical bchaviour of the electrodes made from catalys Pt/C and Pt-PtSn/C are investigated, together with platinum black for purposed of comparison. A new intermcdiate species is suggcsted to be prescnt in the methanol clcctro-oxidation.