The problem of diffusion and reaction in catalyst pellets is considered for the case of nth order reactions. The Adomian decomposition method is used to solve the nonlinear model of diffusion and reaction and to obtain approximate solutions. The variation of reactant concentration in the catalyst pellet and the effectiveness factors are determined for second-, half-and first order reaction. The approximate analytical solutions obtained are compared with solutions obtained with a finite difference numerical method. In general, the Adomian polynomial method with three terms gives solutions comparable to the numerical procedure for Thiele modulus approximately up to 4.0.

The problem of the process of coupled diffusion and reaction in catalyst pellets is considered for the case of second and half order reactions. The Adomian decomposition method is used to solve the non-linear model. For the second, half and first order reac tions, analytical approximate solutions are obtained. The variation of reactant concentration in the catalyst pellet and the effectiveness fac tors at φ<10 are determined and compared with those by the BAND's finite difference numerical method developed by Newman. At low er values of φ, the decomposition solution with 3 terms gives satisfactory agreement with the numerical solution; at higher values of φ, as the term nmnber in the decomposition method is increased, an acceptable agreement between the two methods is achieved. In general the solution with 6 terms gives a satisfactory agreement.

用低温合成法制备出不同Pt掺杂量的Pt-W-Ru-Se催化剂，应用旋转圆盘电极电位扫描法测试其对氧还原反应的催化作用，采用XRD、EDS、XPS技术表征结构及表面组成。结果表明，Pt能够显著增强W-Ru-Se对氧还原反应的催化活性，尤其以含5%Pt（质量分数，下同）的Pt-W-Ru-Se催化剂最为明显，在0.5mol•L-1H2SO4中其对氧还原反应的电催化活性超过了W-Ru-Se和Pt；甲醇存在时，其稳定性和抗甲醇性也都超过了Pt。

应用两步化学还原法合成不同壳层厚度的Fecure-Ptshell纳米粒子，并用SEM、TEM、EDS和XRD手段对其进行物理表征，应用动电位、交流阻抗和循环伏安法进行氧还原电催化活性及抗甲醇性测试。结果表明，样品Fecore-Ptshell纳米颗粒粒径分布集中，其中Fecore-Ptshell0.5平均值为50nm，核芯直径约34nm，壳层厚度约8nm；与Pt/C相比，Fecore-Ptshell/C对氧还原的催化活性和抗甲醇性明显提高，Fe与Pt原子比为1：0.5的Fecore-Ptshell//C在0.5mol•L-1H2SO4中氧还原的最大峰电流密度可达到184.7mA•mg-1，是相同反应条件下Pt/C电流密度的1.45倍。抗甲醇性显著提高。

通过对纯铝板电化学阳极氧化及腐蚀液处理，在～定的条件下制备出了排布有序的Al2O3纳米线，采用SEM、EDS、IR手段对纳米线微观形貌和组成进行了表征。实验结果表明：多孔Al2O3薄膜经腐蚀后形成纳米线，在铝基板上呈六角形排布，组成为纯A1203，直径随电氧化温度、槽电压的升高和腐蚀处理时间的延长减小，直径范围为16～60nm，长径比较大。在实验的基础上，提出了有序排布Al2O3纳米线的形成机理。

预先将活性物前驱体置于碳黑层的Nafion微粒体内，利用脉冲电沉积法，使Pt或Pt合金优先沉积于Nafion与碳黑的接合部，以提高催化剂层贵金属的有效率。实验采用循环伏安法（CV）测定电极电催化活性，用XRD、EDS、TEM技术表征催化剂微观结构及金属微粒的元素组成。结果表明，toff/ton=3：1，wPtRu/wC=40%，Pt、Ru原子比为1：1，金属微粒的比表面积为92m2•g-1、粒径为3。2nm，甲醇峰电流密度达到82mA•cm-2，活性物的有效率达到79.1%。

在低温合成法的基础上缩短催化剂合成时间制得Pt-W-Ru-Se催化剂，用旋转圆盘电极电位扫描法测试其对氧还原反应的催化作用。采用XRD、TEM、XPS进行结构表征。探讨了催化剂的合成时间对氧还原活性的影响。电位扫描法测试结果表明，合成时间短制得的催化剂，对氧还原反应具有较低的电流密度和高的过电位，抗甲醇性能也越盖。

Carbon-supported Pt-Ni catalyst samples were prepared by the colloidal method and characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopic (XPS) and transmission electron microscopy (TEM). Potentiodynamic was used to measure the performance of the electro-catalysts for the oxygen electro-reduction. The results indicate that the Pt-Ni alloy particles are distributed homogeneously on the carbon surface, and their particle sizes are 3-5nm. In the same alkali concentration solution, the activity and methanol-tolerance of Pt nano-particle catalysts are greatly enhanced by doping Ni. For the catalyst, the optimum atom ratio of Pt to Ni is Pt50Ni50/C, and its methanol-tolerance is enhanced markedly as compared with Pt/C. The maximal current of the oxygen electro-reduction over Pt50Ni50/C reaches 106 mA/mg, and the onset over potential is 50 mV less than that over Pt/C in 0.1mol/L KOH solution.

The Pt-Ru-Ho/C catalysts for methanol electro-oxidation have been prepared by pulse electro-deposition method. The activities of catalysts were characterized by cyclic voltammetry (CV) and electrochemical impedance spectrum (EIS). The microstructure and composition of the catalysts were characterized by XRD, EDS and XPS. The results show that Pt-based alloy nano-particles supported on carbon black consist of Pt, Ru, Ho elements, and the particle size and the specific surface of catalysts are about 3.5 nm and 73.3m2•g-1, respectively. The electro-catalytic activity of Pt-Ru/C can markedly be improved by doping with Ho. The optimum mole fraction in Pt-Ru-Ho alloy nano-particle is nPt:nRu:nRu=1:1:0.2. Tafel constant a for Pt-Ru-Ho0.2/C is lower than that of Pt-Ru/C. The reaction order and the active energy of the methanol electro-oxidation are 0.17 and 28.4 kJ•mol-1, respectively.

The effect of platinum loading on the performance of oxygen reduction over Ru-based cluster catalyst in acid electrolytes has been studied by rotating disk electrode. The Pt-Mo-Ru-Se catalysts were synthesized by low temperature method and characterized by XRD, EDS and XPS. The activities were measured by potentiodynamic and AC impedance techniques. The results show that Mo-Ru-Se catalysts doped with platinum were with greatly enhanced catalytic activity and methanol resistance and have higher current density and lower overpotential for oxygen reduction reaction than that of platinum-free Mo-Ru-Se catalysts under the same conditions. The Mo-Ru-Se catalyst with 5% Pt loading showed the best performance, and the peak current density was 213 mA•mg-1 in 0.5 mol•L-1 H2SO4 solution, approached 70% of the Pt activity and the initial oxygen reduction potential was-0.05V.