以炭黑为载体、乙二醇为溶剂, 利用高压微波加热法分别制备了铁系元素(即Fe、Co、Ni三种元素)掺杂的Pt基二元催化剂. 采用TEM、XRD、EDX、XPS等手段分析了催化剂的微观结构. 活性金属粒子在炭黑载体表面分布均匀; Fe、Co、Ni掺杂后, 催化剂中活性金属粒子的粒径分布变窄, 平均粒径明显减小(由4.57nm分别降低至2.17、2.41、2.55nm); 催化剂中Pt存在Pt(0)、Pt(II)、Pt(IV)三种价态. 将催化剂分散于聚四氟乙烯乳液中, 采用自然浸渍法负载于泡沫镍, 制得Pt基疏水催化剂, 考查了其对氢-水液相交换反应的催化活性. 与单一Pt基疏水催化剂相比, 过渡金属掺杂后的二元疏水催化剂对氢-水液相交换反应的催化活性明显提高. 其催化活性由高到低依次为: PtFe/C/FN>PtCo/C/FN>PtNi/C/FN>Pt/C/FN. 催化活性的提高可能主要来源于催化剂活性金属粒径的减小. 此外, H2O分子在Fe系元素表面的解离行为也有一定的贡献.
Pt based binary catalysts, which were adulterated with Feseries elements, viz Fe, Co, and Ni,were prepared using microwave heating method, with carbon black as carrier andglycol as solvent. Microstructure of the catalysts was characterized by TEM, XRD, EDX and XPS. Results showed that active metal particles wereevenly distributed on carrier’s surface. After adulterated by Fe, Co, Ni, thedistribution of active metal particles’ size became narrower and average sizedecreased from 4.57nm to 2.17nm, 2.41nm, 2.55nm, respectively. The catalystswere loaded on foam nickel (FN) with polytetrafluoroethylene latex to obtain Ptbased hydrophobic catalysts, and then their activity for hydrogen-water liquidphase catalytic exchange (LPCE) was tested. Compared with Pt/C/FN hydrophobiccatalyst, the catalytic activity of Pt based binary hydrophobic catalystsadulterated with transition metals increased in evidence. The sequence of thesecatalysts’ activity was as follows, PtFe/C/FN>PtCo/C/FN> PtNi/C/FN>Pt/C/FN. The increase of catalytic activity results from the decrease ofactive metals particles’ size, moreover, it could be attributed to thedissociation property of water on Fe series metals’ surface to some extent.
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