Université Lyon 1, CNRS, UMR 5256, IRCELYON, Institut de recherches sur la catalyse et l'environnement de Lyon, 2 avenue Albert Einstein, F-69626 Villeurbanne, France.
Phys Chem Chem Phys. 2010 Jul 28;12(28):7812-20. doi: 10.1039/b925062j. Epub 2010 May 25.
The decomposition of iridium acetylacetonate Ir(acac)(3) impregnated on amorphous silica-alumina (ASA) has been investigated by combined thermogravimetry-differential thermal analysis-mass spectrometry (TG-DTA-MS) and by in situ X-ray diffraction (XRD). The resulting Ir/ASA hydrotreating catalysts have also been characterized by transmission electron microscopy (TEM). The effects of heating treatments under oxidative, reductive or inert gas flows are compared with each other and with similar experiments on ASA-supported acetylacetone (acacH). It is shown that Ir(acac)(3) undergoes exothermic combustion during calcination in air, leading to agglomerated IrO(2) particles. Conversely, direct reduction involves hydrogenolysis of the acac followed by hydrogenation of the ligand residues to alkanes and water. These two processes are catalyzed by Ir clusters, the gradual growth of which is followed in situ by XRD. The resulting nanoparticles are highly and homogeneously dispersed.
用热重-差热分析-质谱联用（TG-DTA-MS）和原位 X 射线衍射（XRD）研究了浸渍在无定形硅铝酸盐（ASA）上的乙酰丙酮铱（Ir(acac)(3)）的分解。还通过透射电子显微镜（TEM）对所得的 Ir/ASA 加氢处理催化剂进行了表征。比较了在氧化、还原或惰性气流下进行的加热处理与在 ASA 负载的乙酰丙酮（acacH）上进行的类似实验的效果。结果表明，Ir(acac)(3)在空气中煅烧时发生放热燃烧，导致 IrO(2)颗粒团聚。相反，直接还原涉及乙酰丙酮的氢解，随后配体残基加氢生成烷烃和水。这两个过程由 Ir 簇催化，通过 XRD 原位跟踪其逐渐生长。所得的纳米颗粒高度均匀地分散。
