There is a need and opportunity to develop controlled pore diameter/porosity/thickness ultra-thin microporous/mesoporous films on particles. Applications include corrosion protective coatings, gas storage, and catalyst encapsulation for controlling reaction selectivity and for reducing sintering, thus maintaining catalytic activity. Successful completion of this research will result in a better understanding of the fabrication of porous oxide films with controllable thickness and pore size and the design of catalysts that are more resistant to sintering and have higher selectivity. The pore size of the films can be controlled by selection of the organic component in the molecular layer deposited (MLD) hybrid polymer films and the method for removing the organic component, forming pores in the MLD films. Variables to be investigated for the formation of porous films include the effect of MLD precursor chemistry, MLD reaction temperatures, and methods for the formation of porous structures. Because the oxide layers are so thin (1-5 nm), they are not expected to significantly decrease the rate of the desired reaction. Thus, the specific goal is to increase selectivity and lifetime with essentially no loss in rate of the desired reactions. The catalytic properties of supported catalysts could then be designed by selecting the oxide layer thickness, the size of the oxide pores, and the composition of the oxide. The catalysts will be evaluated using oxidation reactions. ALD NanoSolutions, Inc. will provide access to and support for students using a quartz crystal microbalance (QCM) to investigate new MLD chemistries. Additionally, baseline supported Pt/silica gel catalyst to be used for the film and reaction studies will be provided by ALD NanoSolutions, Inc.
Broader Significance and Importance: The ability to prepare highly porous oxide films with controllable thickness and pore size would make generational gains in the preparation of thermally stable catalyst nanoparticles. Since sintering and poisoning are two of the main deactivation mechanisms for catalysts, decreasing the rates of these processes would decrease the amount of precious metals required in catalysts, increase lifetimes and ultimately improve the economics of many processes. The proposed approach has great potential for application in a large number of catalytic processes. Other significant areas for application include controlling the selectivity of membrane separations for sensors and filtration devices, providing a high surface area moiety for functionalization for H2 gas storage or the attachment of active agents for drug delivery, among others. The broader educational application of this proposed research plan is the contribution that is anticipated through the dissemination of results to the particle technology and catalysis communities. This research is not only an excellent vehicle for training a Ph.D. students on an industrially significant project, but is an excellent opportunity to impact undergraduate students and peripheral K-12 outreach. Both graduate and undergraduate students will have opportunities to present their research results at national meetings. From a commercial perspective, ALD NanoSolutions, Inc. has agreed to test market the optimized stabilized Pt catalyst with their potential customers.
