Metal Oxide Nano-array based Monolithic Catalysts for Low Temperature Diesel Oxidation
Pu-Xian Gao, University of Connecticut
The state of the art Pt-group metal (PGM) based emission control catalysts rely on the significant usage of PGM (~1 wt.% loading) with a large amount of support wash-coated on monolithic substrates. The washcoating process lacks control over the physical and chemical structure of the catalysts, substrate adherence and optimum materials utilization efficiency. Recently, through the integration of 3-D catalytic metal oxide nanostructure arrays (nano-arrays) onto channeled monolithic substrates, we have demonstrated significant reduction of the catalyst usage by 10-40 times without sacrificing the catalytic performance. By designing and adjusting the physical structure and chemical composition of nano-arrays, as well as the Pt loading, catalytic oxidation over CO, NO, and HCs can be tuned with high conversion efficiency toward low temperature. The nano-array also offers advantages of structural stability under high temperature or mechanical agitations, and nano-array structure and high surface area facilitated gas-solid interactions. Herein, we report our latest progress on the structure integration, catalytic oxidation property and stability of a few selective metal oxide nano-array based monolithic catalysts, which displays a promising approach toward meeting the 150oC challenge for diesel oxidation catalysts.