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为研究还原温度对Pt/PTFE/泡沫SiC规整疏水催化剂性能的影响,以200、225、250、275、300℃为还原温度,氯铂酸-乙醇溶液为浸渍溶液,采用浸渍-气相还原法制备Pt/PTFE/泡沫SiC规整疏水催化剂。利用接触角测试仪分析还原温度对催化剂疏水性能的影响,利用X射线衍射(XRD)、X射线光电子能谱(XPS)、透射电镜(TEM)等表征手段分析所得催化剂的结构与组成,并研究其氢-水液相催化交换(LPCE)性能。结果表明:还原温度的变化对催化剂疏水性能没有影响;还原温度200、225℃时催化剂中Pt粒子团聚现象严重,Pt粒子粒径大,分散性差;还原温度250、275、300℃时催化剂中Pt粒子粒径分散性较好;还原温度275℃时催化剂中Pt粒子粒径较窄,平均粒径最小,为6.2nm。Pt存在Pt(0)、Pt(Ⅱ)和Pt(Ⅳ)三种价态,还原温度275℃下催化剂中0价Pt所占比例高达72.50%,还原程度高。LPCE催化交换性能也表明,还原温度275℃时催化剂柱效率最高。揭示275℃是所选取还原温度中的最佳还原温度。
In order to study the effect of reduction temperature on the performance of Pt / PTFE / foam SiC structured hydrophobic catalyst, the chloroplatinic acid-ethanol solution was used as the impregnation solution at 200,225,250,275 and 300 ℃, and the impregnation-gas phase reduction method was used Pt / PTFE / foam SiC structured hydrophobic catalyst. The contact angle tester was used to analyze the effect of reduction temperature on the hydrophobicity of the catalyst. The structure and composition of the obtained catalyst were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) Its hydrogen-water liquid phase catalytic exchange (LPCE) performance. The results show that the change of reduction temperature has no effect on the hydrophobicity of the catalyst. At the reduction temperature of 200 and 225 ℃, the agglomeration of Pt particles in the catalyst is serious and the particle size of Pt particles is large with poor dispersibility. When the reduction temperature is 250, 275 and 300 ℃, Pt Particle size dispersion is better; when the reduction temperature is 275 ℃, the particle size of Pt in the catalyst is narrow and the average particle diameter is the smallest, which is 6.2nm. The Pt (Pt), Pt (Ⅱ) and Pt (Ⅳ) have three valence states of Pt, the proportion of 0-valent Pt in the catalyst is as high as 72.50% at 275 ℃ and the degree of reduction is high. LPCE catalytic exchange performance also showed that the catalyst column efficiency is the highest when the reduction temperature is 275 ℃. 275 ° C is the best reduction temperature for the selected reduction temperature.