High-Throughput Screening of Nanoparticle Catalysts Made by Flame Spray Pyrolysis as Hydrocarbon/NO Oxidation Catalysts

Abstract

We describe here the use of liquid-feed flame spray pyrolysis (LF-FSP) to produce high surface area, nonporous, mixed-metal oxide nanopowders that were subsequently subjected to high-throughput screening to assess a set of materials for deNO(x) catalysis and hydrocarbon combustion. We were able to easily screen some 40 LF-FSP produced materials. LF-FSP produces nanopowders that very often consist of kinetic rather than thermodynamic phases. Such materials are difficult to access or are completely inaccessible via traditional catalyst preparation methods. Indeed, our studies identified a set of Ce(1-x)Zr(x)O(2) and Al(2)O(3)-Ce(1-x)Zr(x)O(2) nanopowders that offer surprisingly good activities for both NO(x) reduction and propane/propene oxidation both in high-throughput screening and in continuous flow catalytic studies. All of these catalysts offer activities comparable to traditional Pt/Al(2)O(3) catalysts but without Pt. Thus, although Pt-free, they are quite active for several extremely important emission control reactions, especially considering that these are only first generation materials. Indeed, efforts to dope the active catalysts with Pt actually led to lower catalytic activities. Thus the potential exists to completely change the materials used in emission control devices, especially for high-temperature reactions as these materials have already been exposed to 1500 degrees C; however, much research must be done before this potential is verified.

Embedded Phases: A Way to Active and Stable Catalysts

“…[108] In NO x reduction and propane/propene oxidation processes, these materials showed activities which interestingly, approached those of traditional Pt containing systems but without the need for Pt as a cocatalyst. The formation of (Ce/Zr) 3+ was suggested as responsible for their high catalytic activity.…”

Infrared Thermography as a High-Throughput Tool in Catalysis Research

“…6 Catalysts synthesized by flame spray pyrolysis have been investigated for their activity for hydrocarbon/NO xoxidation in 2009. 15 Recent ecIRT projects deal with hydrogenations 16,17 and hydrodesulfurization, SO 2 oxidation, 18 the oxidation of waste gases in the presence of methyl bromide 19 and the Deacon process. EcIRT has become part of the bachelor of chemistry education at the University of Saarland and is mediated in lectures and laboratory exercises.…”

Design of particles by spray pyrolysis and recent progress in its application

“…Selective catalytic reduction of NO x to N 2 by unburned hydrocarbons can be implemented into the current vehicle system without any engine modification. Weidenhof et al (2009) proposed a high-throughput screening system by using liquid feed spray pyrolysis and reported denox activity of Ce 1−x Zr x O 2 and Al 2 O 3 -Ce 1−x Z r x O 2 nanopowders [105].…”