Engineering of hierarchical metal-zeolite nanocomposites for direct synthesis high-octane gasoline from biosyngas – DirectSynBioFuel

The novelty of this proposal relates to the development of new synthesis strategies for preparation of zeolite-metal composites. Microporous, mesoporous or macroporous crystalline supports will be used as matrix for metal particles because the steric restrictions offered by the cages of zeolites limit the sizes of clusters and thus allow efficient control of metal dispersion. The confinement in cages may hinder cluster interactions and increase cluster stability. The regularity and uniform distribution of metal clusters in zeolite matrix is expected to result in a major increase in the selectivity and higher yields of branched hydrocarbons over metal catalysts. In the final catalysts, the zeolite mesopores will be used for hosting metallic nanoparticles for FT synthesis, while hydrocracking/isomerization of the hydrocarbons will occur in the zeolite micro-, meso- and macropores.

Efficient control of catalyst morphology resulted in the major improvement of the zeolite diffusion properties. Several methods of preparation of catalytically active core-shell metal-zeolite nanocomposites and metal nanoparticle encapsulation in the zeolites were developed. These newly designed catalysts were highly efficient in synthesis of gasoline hydrocarbons in Fischer-Tropsch synthesis.

Novel metal zeolite nanocomposite catalysts with remarkable properties for the application in the direct production of isomerized paraffins from syngas were designed. These new strategies can used for the design of bifunctional catalysts for other important catalytic reactions.

Several papers submitted to top catalysis journals, oral presentations at EuropaCat congress, European zeolite congress and Brazilian catalysis congress.

The present proposal focuses on the design of new synthetic strategies for the preparation of hierarchical nanocomposites of metal and zeolite and their application for direct synthesis of high-octane gasoline from biosyngas. A new method will be used for the synthesis of hierarchical zeolites with controllable size of secondary (meso- ou macro-)pore network. This method offers the advantage to retain the intrinsic properties of parent zeolite. Thus, a zeolite material with improved mass transport and desired acidity can be obtained. The method allows also controlled formation of secondary pores/cavities in zeolite crystals, which will serve as a matrix for metallic nanoparticles. Mono- and bimetallic nanoparticles of given shape and size will be prepared in the colloidal systems. Their size and morphology will be varied by the efficient control of the synthesis procedure. Colloidal nanoparticles of Co, Fe or Ru for Fischer-Tropsch synthesis will be incorporated into the cavities. The metal nanoparticles will be pre-formed and then nanocasted in zeolite matrix. This way of preparation will allow fine control of metal particles composition, shape and size. Finally, secondary growth of zeolite crystals will be elaborated in order to encapsulate the metals in zeolite matrix. These strategies will provide composites containing nanoparticles of desired size that exhibit close nanoscale contact with zeolite phase. The intimate contact between the metallic particles of predetermined size and zeolite matrix is expected to yield high octane bio-gasoline and to suppress or to limit the formation of undesirable products.