Innovative method for the preparation of catalytic surfaces: The application of microorganisms for the deposition of nanoparticles on supports

Most catalysts in use are supported systems where metallic or oxide active phases, usually nanocrystals, are spread over the surface of high-area carriers. Despite dynamic progress, the art and science of catalyst preparation still remain centre stage. Herein, the innovatively prepared catalysts using nonpathogenic bacteria to capture nanoparticles and deposit them on various supports by leveraging the microbial “race for the surface” is presented. It was demonstrated that bacteria are effective biocarriers for the capture, transport, and controlled dispersion of metallic (gold, platinum) and oxide (titania, magnetite) nanoparticles on carbon, alumina, zirconia, and cordierite support surfaces. Next, the bacteria are effectively removed with oxygen plasma or transformed into a carbon film of various compositions and morphologies. The conceptual proposal is substantiated by a feasibility study showing several successful preparations of various supported catalysts via the use of microorganisms, which may be extended to other applications.