PEMFC催化剂的研究：自制抗CO中毒Pt-Ru/C电催化剂的性质

用胶体法制备了抗CO中毒PEMFC阳极Pt-Ru/C电催化剂（标记为THYT－2），对 比研究了THYT－2与Johnson Matthey (JM)公司同类品牌Pt-Ru/C催化剂的电化学及 其它物理化学性能。结果表明，THYT－2电催化剂在甲醇燃料电池和CO／H_2（Φ_ (CO) = 1 * 10~(-4)）的氢氧燃料电池中的电催化行为与JM催化剂相当，但THYT－ 2在低浓度CO氢气燃料中的电池性能更好。两种催化剂的其它物理化学性质具有类 似性：XPS分析结果表明THYT－2和JM催化剂 中都有三种不同价态的Pt存在：即金 属态Pt(0)、氧化态Pt(II)和Pt(IV)。HRTEM测试结果表明两种催化剂的粒径处在2 ～3 mn左右，这可能是它们拥有良好电化学性能的主要原因之一。本文还对催化剂 中Pt与Ru组分的分布和相互作用进行了讨论，提出了改进Pt-Ru/C电催化剂的思路 。

Study of Pemfc Electro-Catalysts: Characteristics of a Homemade CO- Tolerant Pt-Ru/C Catalyst

A homemade Pt-Ru/C catalyst (named THYT-2) was characterized and used as CO-tolerant electrocatalyst for the proton-exchange membrane fuel cell (PEMFC), While THYT-2 showed comparable electrocatalytic activity with that of the commercial Pt-Ru/C catalyst (Johnson Matthey Corporation ) by the single-cell performance with CO/ H_2(Φ_(CO)- 1*10~(-4)) or methanol as the fuel, higher resistance toward CO- poisoning was demonstrated when the CO-concentration in the hydrogen fuel was reduced to 1*10 ~(-5). The electrochemical oxidation of CO on THYT-2 and the Johnson Matthey Pt-Ru/C catalysts was also indistinguishable by the results of CO-stripping experiment. XRD and XPS measurements show that 60% of the platinum in both catalysts existed in the metallic state of Pt(O) and the other 40% in oxidized Pt(II) and Pt(IV) states. High-resolution TEM detection demonstrates uniformly dispersed Pt-Ru crystals with sizes of 2-3 ran of both catalysts, but selected area EDX analysis reveals non-uniform distribution of ruthenium in the Pt-Ru nano-crystals, which suggest that further improvement of the electrocatalyst can be made with deliberate control of the distribution and interaction of the two metal components.