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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 Pd @ Pt nanoparticles with core-shell structure were successfully synthesized by sol method using PVP and oleylamine as stabilizers.The synthesized nanoparticles were characterized by TEM, EDS and IR-CO The catalytic performance of Pt / Al_2O_3 and Pd @ Pt / Al_2O_3 in de-NO_x hydrogenation was investigated.The experimental results show that the sol-gel method can effectively control the size of the synthesized Pt nanoparticles, In the reaction, small size Pt nanoparticles showed higher reactivity. In addition, when the reaction conditions were H 2 / NO = 4/1, the main product of de-NO x reaction was ammonia. Under the reaction conditions of H 2 / NO = 1 / 1, the reaction is more prone to generate N_2. Under the same reaction conditions, the core-shell Pd @ Pt / Al_2O_3 nanoparticles have the highest catalytic performance in the de-NO_x reaction compared with the small size Pt nanoparticles , Which significantly improved the selectivity of N 2, which reached 62% of the maximum value at 150 ℃, which was more than twice as much as that of the single metal Pt 4.5 / Al 2 O 3 catalyst. This may be attributed to the combination of Pd in the core layer and Pt in the shell The interaction between atoms changes the extraterrestrial electronic properties of Pt.