Highly Selective, Active, and Stable Metal Nanoparticle Catalysts with Ultra-Thin Porous Ceramic Shells for Size-Selective Chemical Reactions

Size-selective catalysts with metal cores and porous shell structures can increase reaction selectivity through molecular discrimination of reactants. The selectivity of a catalyst can be improved by tuning the pore size of the porous films. However, selectivity is generally improved at the expense of catalytic reactivity. The proposed project is aimed at developing methods for preparing nanostructured size-selective catalysts that exhibit both high selectivity and activity. The proposed strategy for size-selective catalyst preparation can be applied to a great variety of supported metal catalysts and may also find applications in other fields, including sensors, fuel cells, batteries, and supercapacitors. The primary objectives of this project are: (a) to develop a novel nanostructured size-selective catalyst with a nanoscale (less than 5 nm thick) porous ceramic overlayer capped on every metal nanoparticle surface and (b) to gain a fundamental understanding of the structure-activity-selectivity relationships of the catalysts. A unique molecular layer deposition (MLD) technique will be utilized to synthesize the highly porous overlayers with precise thickness control and well-defined porous structures. The sizes of pores can be controlled by altering MLD chemistry, oxide types, and formation methods of porous structures. There is a plan to introduce results from this project into the Chemical Engineering curriculum at Missouri S&T and develop a new course: "Nanotechnology in Catalysis". Graduate and undergraduate students will be recruited to participate in this research project with special emphasis on recruiting underrepresented minorities through a collaboration with Lincoln University of Missouri - an 1890 Historically Black College & University. An annual " Nanomaterials Show" will be developed and used to stimulate interest of general audiences and K-12 students in the field chemical engineering and nanotechnology. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.