WILL BE POSTPONED TO A LATER DATE
Iron based Organometallic Nanoparticles for Magnetically Induced Catalysis
Prof. Dr. Bruno Chaudret
Institut National des Sciences Appliquées, Laboratoire de Physique et Chimie des Nano-Objets
Magnetic nanoparticles display both interesting core physical properties and interesting surface chemical properties. The composition of the particles allows to modulate their magnetic properties in terms of saturation magnetization, magnetic anisotropy and Curie temperature and hence heating power. Thus magnetic nanoparticles heat when submitted to an alternating magnetic field. Magnetic heating is instantaneous and in principle the best way to transform electrical energy into heat. For this purpose we have developed in Toulouse a new generation of iron based nanoparticles of unprecedented heating power. Iron carbide particles are prepared by carbidization of preformed monodisperse Fe(0) nanoparticles under a CO/H2 atmosphere at 150°C. They consist essentially of crystalline Fe2.2C, display a SAR (heating power) of up to 3.3 kW/g and are able to hydrogenate CO2 into methane in a flow reactor after addition of a catalytic Ru or Ni layer and excitation by an alternating magnetic field. Iron nickel nanoparticles have been synthesized from iron amide and nickel amidinate precursors and found very active for CO2 hydrogenation. Iron cobalt nanoparticles display a much higher Curie temperature and can be used for high temperature catalysis such as propane or methane dry reforming and propane dehydrogenation.
In addition, submitting nanoparticles of iron carbide or iron nickel to magnetic heating in solution leads to local over-heating and to perform under a low H2 pressure difficult reactions such as hydrodeoxygenation of biomass derived platform molecules.
The lecture will present the synthesis of the particles, their magnetic properties, their surface modification to deposit a catalytic layer and their catalytic properties for CO2 hydrogenation in a flow reactor and high temperature catalysis. Further developments of the technique in solution or for electrochemical reactions will also be described.