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采用多元醇法制备了 n( Pt) /n( Sn)比为 2∶ 1 ,3∶ 1 ,4∶ 1的 Pt Sn/C电催化剂 .通过 XRD,TEM、循环伏安和氢化学吸附技术对催化剂进行了表征 . TEM和 XRD结果表明 ,不同比例的 Pt Sn/C金属粒子的平均粒径均小于 4nm,且粒径分布较窄 ;该系列催化剂中 Pt具有 fcc结构 ;Pt Sn间的相互作用使 Pt晶格参数增大 .循环伏安和氢化学吸附实验结果表明 ,加入 Sn可抑制 Pt对氢的吸附 ,Pt3Sn/C对乙醇的氧化电流比Pt4 Sn/C高约 1倍 .用不同 n( Pt) /n( Sn)比的催化剂作为直接醇类燃料电池阳极电催化剂 ,在相同条件下 ,随着 Sn含量的增加 ,单电池最大输出功率逐渐增大 ,当 Sn含量继续增大时 ,单池性能反而下降 .导致不同比例 Pt Sn催化剂活性差别的原因可能是由于 Sn与 Pt间的合金化程度不同和催化剂粒子尺寸效应及 Sn含量对电池阻抗等几方面因素所致 .对 40 h寿命测试前后的阳极 Pt3Sn/C催化剂的分析 ( Energy dispersive X-rayanalysis,EDX)结果表明 ,Pt Sn含量在测试前后均有所降低 ,Pt Sn催化剂的寿命尚有待改善
The Pt Sn / C electrocatalyst with n (Pt) / n (Sn) ratio of 2: 1, 3: 1 and 4: 1 was prepared by the polyhydric alcohol method. The results of TEM and XRD show that the average particle sizes of Pt Sn / C metal particles with different ratios are all less than 4 nm and the particle size distribution is narrow. Pt has fcc structure and Pt Sn interaction The experimental results of cyclic voltammetry and hydrogen chemisorption showed that addition of Sn could inhibit the adsorption of hydrogen on Pt, and the oxidation current of Pt3Sn / C to ethanol was about 1 times higher than that of Pt4Sn / C. With different n (Pt) / n (Sn) ratio as the anode electrocatalyst for direct alcohol fuel cell, under the same conditions, with the increase of Sn content, the maximum output power of single cell gradually increases. When the Sn content continues to increase, The performance of the single cell decreased but the reason for the difference in the activity of Pt-Sn catalysts was probably due to the different degree of alloying between Sn and Pt, the size effect of catalyst particles and the Sn content on the cell impedance, Anode Pt3Sn / C catalyst before and after the test Analysis (Energy dispersive X-rayanalysis, EDX) results showed that, Pt Sn content is reduced before and after the test are, Pt Sn catalysts life remains to be improved