为了研究载体对铂(Pt)基疏水催化剂活性的影响,分别选取了炭黑、SiC纳米粉、铈锆复合氧化物(Ce_(0.4)Zr_(0.6)O_2-γ-Al_2O_3)等三种物质,在氯铂酸的乙二醇溶液中,用高压微波加热法制备了Pt基催化剂,然后将其与聚四氟乙烯一起负载于泡沫镍上,制成疏水催化剂.用X射线衍射、透射电子显微镜、X光电子能谱、扫描电子显微镜等方法分析了催化剂的结构与组成,并研究了疏水催化剂对氢-氧复合反应及氢-水交换反应的催化活性.结果表明:Pt在载体表面分布均匀,在Pt/C、Pt/SiC、Pt/Ce_(0.4)Zr_(0.6)O_2-γ-Al_2O_3中Pt的平均粒径分别为4.46、1.67和1.77nm;Pt/C、Pt/SiC催化剂中Pt存在Pt(0)、PI(Ⅱ)和Pt(Ⅳ)三种价态;Pt/C、Pt/SiC在泡沫镍表面的分布均匀,而Pt/Ce_(0.4)Zr_(0.6)_O_2-γ-Al_2O_3分布不均匀.Pt/C/FN对氢-氧复合反应和氢-水交换反应的催化活性都较高;Pt/SiC/FN和Pt/Ce_(0.4)Zr_(0.6)O_2-γ-Al_2O_3/FN对氢-氧复合反应的催化活性高,但是对氢-水交换反应的催化活性很低.
In order to study the influence of carriers on platinum (Pt) based hydrophobic catalysts' activity,and explore the practicability of applying silicon carbide and cerium-zirconium composite oxides as carriers of hydrophobic catalysts, Pt based catalysts were prepared by microwave heating method, with carbon black,nanometer SiC and Ce_(0.4)Zr_(0.6)O_2-γ-Al_2O_3 as carriers, respectively. Then Pt based catalysts were loaded on foam nickel (FN) with polytetrafluoroethylene latex, and hydrophobic catalysts were obtained. Structure of catalysts was analyzed by XRD, TEM, XPS, SEM, etc, moreover, their catalytic activity for recombination of H_2-O_2 and hydrogen-water liquid catalytic exchange was tested. Results show that Pt particles are evenly distributed on carriers' surface, and average size of Pt particles in Pt/C, Pt/SiC and Pt/Ce_(0.4)Zr_(0.6)O_2-γ-Al_2O_3 are 4.46, 1.67 and 1.77nm, respectively. Three valences, Pt (0), Pt (Ⅱ) and Pt (Ⅳ) exist in Pt/C and Pt/SiC catalysts. Pt/C and Pt/SiC catalyst particles are evenly distributed on the surface of foam nickel, but it is not the case for Pt/Ce_(0.4)Zr_(0.6)O_2-γ-Al_2O_3. The catalytic activity of Pt/C/FN is quite high for both recombination of H_2-O_2 and hydrogen-water liquid catalytic exchange. The catalytic activities of Pt/SiC/FN and Pt/Ce_(0.4)Zr_(0.6)O_2-γ-Al_2O_3/FN are high for recombination of H_2-O_2, however, they are quite low for hydrogen-water liquid catalytic exchange.
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