Pd@Pt核壳型纳米粒子的制备及其在de-No_x加氢反应中的催化性能研究  

Preparation of Core-shell Pd@Pt Nanoparticles and Application in Hydrogenation de-NO_x Reaction

作　　者：胡滨[1,2] 熊春荣[1] 陶凯[2] 周生虎[2] 

机构地区：[1]海南大学材料与化工学院,海口570228 [2]中国科学院宁波材料技术与工程研究所,宁波315201

出　　处：《复旦学报（自然科学版）》2014年第2期221-227,共7页Journal of Fudan University：Natural Science

基　　金：宁波市自然科学基金资助项目(2013A610036)

摘　　要：以PVP、油胺作为稳定剂,采用溶胶法成功合成了不同尺寸的Pt纳米颗粒,以及具有核壳结构的Pd@Pt纳米颗粒.采用TEM,EDS,IR-CO对合成的纳米粒子进行了表征,并考察了Pt/Al_2O-3以及Pd@Pt/Al_2O_3在de-NO_x加氢反应中的催化性能.实验结果表明:溶胶法可以有效控制所合成的Pt纳米颗粒的尺寸,且在deNO_x加氢反应中,小尺寸的Pt纳米颗粒显示出了更高的反应活性.此外当反应条件为H_2/NO=4/1时,de-NO_x反应主产物为氨;在反应条件为H_2/NO=1/1时,该反应更倾向于生成N_2.在相同的反应条件下,与小尺寸的Pt纳米颗粒相比,核壳型Pd@Pt/Al_2O_3纳米颗粒在de-NO_x反应中具有最高的催化性能,显著提升了N_2的选择性,在150℃时N_2含量达到最大值62%,是单金属Pt_(4.5)/Al_2O_3催化剂的两倍以上.这可能是由于核层的Pd与壳层的Pt之间的相互作用改变了金属Pt的核外电子性质而引起的.Pt nanoparticles with different sizes and core-shell Pd@Pt nanoparticles were successfully synthesized using a PVP or oleylamine as the stabilizer. All nanoparticles were characterized by TEM, EDS and IR-CO. Pt/ Al2O3 and Pd@ Pt/Al2O3 catalysts were tested in packed bed reactor for the catalytic de-NOx reaction with hydrogen. The results showed that the smaller Pt nanoparticles displayed a higher reactivity. Additionally, the principal product of de-NOx was ammonia when the H2/NO ratio was 4, and it was N2 for the H2/NO ratio of 1. The core-shell Pd@Pt/Al2O3 catalyst showed a remarkably enhanced N2 selectivity of 62% at 150 ℃, over twice of that for the Pt4.5/Al2O3 catalyst. The improved catalytic performance might be caused by the interaction between Pd core and Pt shell.

关 键 词：尺寸效应 核壳结构 Pd@Pt DE-NOX 

分 类 号：O614.3[理学—无机化学]