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采用调变的多元醇法制备了高分散碳载PtSn催化剂(PtSn/C),XRD测试结果表明金属粒子的平均粒径为2.2nm,略小于Pt/C催化剂,而晶格参数相对增大。通过电化学原位时间分辨红外光谱研究了乙醇在PtSn/C催化剂上的吸附和氧化过程,表明线性吸附态CO(COL)是主要的乙醇解离吸附物种,导致催化剂中毒,阻止反应继续进行;当电位增大到0.3V时,出现了乙醛和乙酸的红外吸收峰,作为乙醇解离吸附的竞争反应,乙醛和乙酸的生成有效抑制了催化剂中毒,随着电位的增大和时间的延长,生成乙酸的选择性增大;电位进一步增大至0.4V时有微弱CO2吸收峰出现,是乙醇电氧化的最终产物,主要来自于COL的氧化消耗。根据实验结果讨论了PtSn/C催化剂上乙醇的电催化氧化机理。
The PtSn / C catalyst was prepared by a modified polyol method. The results of XRD showed that the average particle size of the metal particles was 2.2 nm, slightly smaller than that of the Pt / C catalyst, and the lattice parameters were relatively increased. The adsorption and oxidation of ethanol on PtSn / C catalyst were studied by electrochemical in situ time-resolved FTIR. The results showed that the linear adsorption state of CO (COL) was the main ethanol dissociative adsorbent species, which led to catalyst poisoning and prevented the reaction from proceeding. When the potential increases to 0.3V, there is the infrared absorption peak of acetaldehyde and acetic acid. As a competitive reaction of ethanol dissociative adsorption, the formation of acetaldehyde and acetic acid effectively inhibits the catalyst poisoning. With the increase of potential and time , And the selectivity to acetic acid increased. When the potential was further increased to 0.4V, there was a weak CO2 absorption peak, which was the final product of electrooxidation of ethanol, mainly from the oxidative depletion of COL. The electrocatalytic oxidation mechanism of ethanol on PtSn / C catalyst was discussed based on the experimental results.