纤维状中孔硅胶KCC-1负载的钯纳米颗粒上甲酸催化脱氢反应（英文）

Catalytic dehydrogenation of formic acid over palladium nanoparticles immobilized on fibrous mesoporous silica KCC-1

在N-(3-三甲氧基硅丙基)二乙烯三胺(PDETA)功能化的纤维状硅胶KCC-1上负载了均一的、平均粒径为2.8 nm的Pd纳米粒子(Pd/KCC-1-PDETA),采用粉末X射线衍射、X射线光电子能谱和N2吸附-脱附等温线对其进行了表征,并将其作为催化剂用于无添加剂的甲酸脱氢制H2的反应中.同时还制备了另外两个中孔硅胶材料(MSF和KIT-6)负载的Pd纳米粒子,以考察反应中催化剂的载体效应.结果表明, Pd/KCC-1-PDETA催化剂表现出很高的催化性能(323 K时TOF值为332 h-1,氢气选择性100%).这归结为KCC-1独特的纤维状形貌和胺基基团的存在,从而降低了Pd颗粒尺寸,促进了反应物与催化活性位Pd的接触.还考察了Pd负载量(2–10 wt%)、反应温度和反应时间对脱氢反应性能的影响.反应结束后,Pd/KCC-1-PDETA催化剂容易回收,可重复使用5次而催化性能未见明显下降,表现出较好的重复使用性能.

Uniform Pd nanoparticles immobilized on N-(3-trimethoxysilylpropyl)diethylenetriamine (PDETA)-functionalized fibrous silica KCC-1 (Pd/KCC-1-PDETA) were prepared with a mean Pd particle size of 2.8 nm. After characterization using powder X-ray diffraction, X-ray photoelectron spectroscopy, and N2 adsorption-desorption isotherms, Pd/KCC-1-PDETA was used as catalyst for additive-free dehydrogenation of formic acid to produce H2. Pd nanoparticle catalysts supported on two other mesoporous silica materials (MSF and KIT-6) were also synthesized to examine how the support affects the reaction. Among the three catalysts, Pd/KCC-1-PDETA exhibited significant catalytic activity (a turnover frequency of 332 h?1 at 323 K and 100% selectivity towards hydrogen), owing to the unique fibrous morphology of KCC-1 and the presence of amine groups that reduced the Pd particle size and improved the access of reactant to the catalytically active Pd sites. The influence of Pd loading (2–10 wt.%), reaction temperature, and reaction time was also examined for the dehydrogenation reaction. Pd/KCC-1-PDETA was recovered easily after the reaction and showed good reusability up to five times without any significant loss in catalytic performance.