CVD

Functionalization of nanoscaled particles in the aerosol state by CVD

The ParteQ process for particle functionalization is based on the coating of metals or oxides by chemical vapor phase deposition (CVD). The process enables a unique degree of control over structural features such as size and surface texture of support particles and size and number density of supported metal particles or the thickness of oxide shells. We can generate a vast variety of structures, from simple mixed oxides over supported metal islands to core-shell structures and Janus-particles.

The technique was originally developed as an aerosol process, which allows extreme control but low product yields. Some examples of structures obtainable with the aerosol process are shown below. The images at the top show noble metal particles of about 2 nm in diameter on the surface of oxide support particles. The lower TEM-image on the left shows a multilayer coating of bismuth oxide on a second oxide layer coating a binary oxide core while the right hand side shows a Janus-like particle.To increase the product yield and to obtain scalability the process was transformed into a fluidized bed system.

 

The system allows the functionalization of micropowders on the nanoscale but avoids the necessity of handling nanopowders which is advantageous in further processing but also from an environmental health and safety point of view. Our fluidized bed reactors are heatable up to 200°C allowing thermal CVD processes. They are vacuum tight and can therefore be operated with reactive atmospheres and for the processing of air- or humidity sensitive systems. ParteQ offers systems from the lab-scale to pilot scale as complete systems including precursor dosing, and solids handling.