Compared activities of platinum and high specific surface area Mo2C and WC catalysts for reforming reactionsI. Catalyst activation and stabilization: Reaction of n-hexane
A facile preparation of nanocrystalline Mo2C from graphite or carbon nanotubes
摘要:
Nanocrystalline Mo2C powders were successfully synthesized at 500 degrees C by reacting molybdenum chloride (MoCl5) with C (graphite or carbon nanotube) in metallic sodium medium. X-ray powder diffractometer (XRD), transmission electron microscope (TEM), X-ray photoelectron spectroscope (XPS) and surface area analyzer (BET method) were used to characterize the samples. Experiments reveal that the carbon source used for the carbide synthesis has a great effect on the particle size and the surface area of the samples. When micro-sized graphite was used as C source the obtained nanocrystalline Mo2C powder consists of particles of 30-100nm, with a surface area of 2.311 m(2)/g. When carbon nanotubes were used as C source, the as-synthesized Mo2C sample is composed of particles of 20 similar to 50 nm, with a surface area of 23.458 m(2)/g, which is an order of magnitude larger than that of the carbide prepared from the graphite. (c) 2005 Elsevier Inc. All rights reserved.
surface, accomplishing the selectivehydrogenation of α,β‐unsaturatedaldehydes on negatively charged Irδ− species. The combined experimental and theoretical investigations showed that the Irδ− species derive from the higher work function of Ir (vs. Mo2C) and the consequently electron transfer. In crotonaldehyde hydrogenation, Ir/Mo2C delivered a crotyl alcohol selectivity as high as 80 %, outperforming
需要金属与载体的相互作用来优化金属上的催化转化。在本文中,通过使用Mo 2 C纳米线载体增强的相互作用来修饰Ir表面的电荷密度,从而实现在带负电的Irδ-物种上进行α,β-不饱和醛的选择性氢化。结合实验和理论研究表明,Irδ-物种源自Ir(相对于Mo 2 C)的较高功函,因而源自电子转移。在巴豆醛加氢中,Ir / Mo 2C提供了高达80%的巴豆醇选择性,优于硅胶上对应的巴豆醇(<30%)。此外,还证实了Pt和Au具有这种电子金属-载体相互作用,与之相比,Ir / Mo 2 C具有较高的选择性和较好的活性,因此得到了强调。此外,对各种底物的功效进一步证明了我们的Ir / Mo 2 C系统在化学选择性氢化方面具有竞争力。
Selective gas phase hydrogenation of nitroarenes over Mo<sub>2</sub>C-supported Au–Pd
作者:Xiaodong Wang、Noémie Perret、Laurent Delannoy、Catherine Louis、Mark A. Keane
DOI:10.1039/c6cy00514d
日期:——
The first reported synthesis of Au–Pd/Mo2C from colloidal nanoparticles with enhanced selective catalytic hydrogenation of functionalised nitroarenes.
首次报道了从胶体纳米颗粒合成Au-Pd/Mo2C,并实现了对官能化硝基芳烃的增强选择性催化加氢。
Preparation of nanostructured molybdenum carbides for CO hydrogenation
作者:Changcheng Liu、Minggui Lin、Kegong Fang、Yan Meng、Yuhan Sun
DOI:10.1039/c4ra01586j
日期:——
Novel Mo2C/C nano/microcomposites were prepared via a facile approach involving the hydrothermal carbonization of a solution of glucose as a carbon precursor in the presence of ammoniumheptamolybdatetetrahydrate. The samples were subsequently characterized by X-ray diffraction, X-ray photoelectron spectroscopy, thermal gravimetric analysis, N2-physisorption, scanning electron microscopy and high-resolution
通过一种简便的方法制备了新颖的Mo 2 C / C纳米/微复合材料,该方法涉及在四水合七钼酸铵存在下对作为碳前体的葡萄糖溶液进行水热碳化。随后通过X射线衍射,X射线光电子能谱,热重分析,N 2-物理吸附,扫描电子显微镜和高分辨率透射电子显微镜对样品进行表征。碳化剂的作用(Ar,CH 4 / H 2 = 0.2和H 2)进行了调查。特别地,广泛研究了碳化过程中催化剂的碳化行为和Mo物种的演化以及对高级醇合成的CO加氢的影响。在碳化步骤中,催化剂结构经历了广泛的重组过程,这又引发了高级醇合成中的不同性能。而且,通过这种方法合成的纳米结构的碳化钼在用于高级醇合成的CO加氢中表现出优异的性能。
Pyridine Hydrodenitrogenation over Molybdenum Carbide Catalysts
作者:J.G. Choi、J.R. Brenner、L.T. Thompson
DOI:10.1006/jcat.1995.1143
日期:1995.6
hydrotreatment catalysts. Pyridine hydroenitrogenation over the Mo carbides appeared to be structure-sensitive as the activity and selectivity varied with changes in the surface area. Selectivities over the carbides were significantly different from those over the Mo nitride and sulfide catalysts. While the Mo carbides produced substantial amounts of cyclopentane, the Mo nitrides and the sulfided catalysts produced