Catalysis by Flame Synthesized Supported Gold Nano-Particles
Sachit Chopra1, Jeroen van Bokhoven2, Jagdeep Singh2, and Gregory Beaucage1. (1) Department of Chemical and Materials Engineering, University of Cincinnati, Cincinnati, OH 45221-0012, (2) Institute for Chemical and Bioengineering, ETH Zurich, HCI E1127, Zurich, 8093, Switzerland
We investigated the catalytic properties of supported gold nanoparticles synthesized using Spray Flame Pyrolysis (SFP) for the CO oxidation reaction. The ability of supported Au nanoparticles to catalyze low-temperature oxidation of CO is of interest from both theoretical and practical view point. We evaluate the flame synthesized supported gold nanoparticles on TiO2, Al2O3, SiO2 and Fe2O3 supports, and compare their performance against the deposition-precipitation synthesized catalysts. We present the effect of oxidizing and reducing pretreatments on the catalytic activity. We used in-situ XAS to understand the reaction pathway of CO and O2 over gold in order to determine the oxidation state of the most active gold species. The supports produced in the flame appear to be markedly different from those used in the solution methods. Comparison is also made of the nano-structure using SAXS and TEM as well as the molecular structure using XAFS. Anomalous SAXS is used to distinguish between the ceramic supports nano-structure and the nanostructure of the supported gold particles.
Supported by the US NSF through International Research and Education in Engineering (IREE)and CBET 0626063 grants as well as by the Swiss NSF.