Pu-Xian Gao, Tianfeng Lu, Zhuyin Ren, and Steven Suib University of Connecticut
Hydrothermal processing has emerged as a potentially economic method for nanomanufacturing, due to energy saving, cost effectiveness, simplicity and low operation temperature (LOT). However, the scientific nature of hydrothermal processing remains elusive, particularly on the spatial distribution of nanostructure nucleation and growth, patterning and self-assembly into device forms, which directly impact the assembly (device) yield, growth rate, uniformity, and batch-to-batch repeatability. The goal of this project is to design and validate an external-energy-field assisted flow hydrothermal manufacturing technique for continuous, scalable and sustainable syntheses of a new class of monolithic catalysts, based on three-dimensional (3-D) nanostructure arrays (nano-array), for low temperature catalytic diesel oxidation, and to understand the underlying mass transport and growth reaction chemistry. With well-defined size, shape and orientation, nano-arrays on monoliths will be synthesized based on selective metal oxides, targeting from the lab-scale, large-scale, to industrially relevant manufacturing stages. Both stirred batch and continuous flow reactor techniques will be systematically studied in combination with production-rate-acceleration external energies such as electrical fields, microwaves and ultrasonic radiation. Computational fluid dynamics will be used to design and optimize catalysts based on theoretical analyses and numerical modeling using. Detailed flow field distributions, chemical kinetics, and experimental validation will guide the design and control of the field-assisted growth reactors. Various metal doping will be conducted on the nano-arrays to enable LOT activity and selectivity for catalytic diesel oxidations. These structured nanocatalysts will be tested and validated as low temperature diesel oxidation catalysts (DOC) for hydrocarbon and nitrogen oxide oxidations.
This project will provide new insights on the thermodynamic, transport and growth behavior of nanomaterial assemblies at a 3-D monolithic device/system level, as accelerated by external energy field implementation. The resulting structured nanocatalysts will provide a much needed class of LOT DOCs for the automotive industry, and will directly impact the fuel economy, energy and environmental sustainability. Such arrays will also provide a unique device platform applicable in chemical, mechanical, and biotechnology industries. The complementary experimental and modeling study for hydrothermal manufacturing could be applied to other nanomanufacturing cases involving solution or gas phases. This project emphasizes interdisciplinary education and training involving materials science, chemical engineering, chemistry, and mechanical engineering, as well as the strong industrial partnerships with United Technologies Corporation, Umicore, VeruTEK, and ANSYS.
A summer workshop on "Advanced Nanomaterials: Manufacturing and Processing" will be hosted every year by the PIs and industrial partners, targeting community college students and high school teachers, who will eventually influence a number of underrepresented minority students, forming a potential workforce for nanomanufacturing industry of the future. A summer lab course will be held for K-12 students in the Kids Are Scientists Too Program. A ?Nano-Array Catalysts? theme website will be created to disseminate information from this project with a separate access set up for the general public. In the third year of the project an international conference will be held on ?Catalytic Nanomaterials Manufacturing? at UCONN.
