OMCVD ON FLUIDIZED DIVIDED SUBSTRATES - A POTENTIAL METHOD FOR THE PREPARATION OF CATALYSTS

The OMCVD method has been used to deposit highly pure metal particles on porous divided substrates in order to prepare metal supported catal ysts. A fluidized bed reactor has been especially designed and the req uirements of CVD and fluidization have been taken into account to sele ct convenient experimental conditions. Three organometallic compounds of rhodium have been selected and their thermal decomposition under He and He/H2 mixtures studied by infrared spectroscopy and on-line mass spectrometry analyses. The deposition are carried out at a total press ure of 100 Torr and substrate temperatures as low as 100 degrees C. Th e solid deposits have been characterized by XPS, the size and dispersi on of the particules have been determined by chemisorption methods or measured by TEM. These catalysts can be used without further treatment and their performances have been compared to those of conventionally prepared ones.