| Nanogold Particle-Oxide Interaction for the Water Gas Shift Reaction | ||
| Danny Pierre1, Maria Flytzani-Stephanopoulos1, Mark E. Bussell2, Weiling Deng1 and Gajanthan Balakaneshan1, (1)Chemical and Biological Engineering, Tufts University, 4 Colby Street, Medford, MA 02155, (2)Chemistry Department, Western Washington University, 516 High Street, MS-9150, Bellingham, WA 98225-9150
The importance of nanogold–oxide interaction for CO oxidation reactions has been discussed extensively in the literature. For the water-gas shift (WGS) reaction, our group has shown that there is a strong interaction between gold and cerium oxide. The presence of gold ions on the defect sites of ceria is a key feature of Au-ceria catalysts [1-3]. The importance of metallic gold nanoparticles has also been argued in the literature [4]. Conventional techniques such as co-precipitation, deposition-precipitation, and cogelation are typically used to prepare these catalysts. Recently the use of reverse micellar systems has been reexamined due to their ability to make highly structured uniform catalysts [5]. The technique has already been used to make both encapsulated Pt and Pd catalysts for butane combustion [6]. In this work, we look at several nano gold-oxide materials; namely Au/SiO2, Au/CeO2-doped SiO2, and Au/Fe2O3 for the WGS reaction. Materials included encapsulated gold within a shell of oxide (via the reverse micelle technique) and traditionally structured catalysts. The catalysts were characterized by high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), BET surface area and H2S temperature-programmed desorption (TPD) measurements, as well as by H2 and CO temperature-programmed reduction (TPR). Catalyst activities were evaluated for the WGS reaction under various conditions that included product-free and full reformate gas mixtures, as well as in the presence and absence of ppm levels of H2S to investigate the effects of poisons. References: 1. Q. Fu, H. Saltsburg, and M. Flytzani-Stephanopoulos, Science 301 (2003) 935-938 2. Q. Fu, W. Deng, H. Saltsburg, and M. Flytzani-Stephanopoulos, Applied Catalysis B 56 (2005) 57-68. 3. ZP Liu, SJ Jenkins, and DA King, Physical Review Letters 94 (2005) 4. H. Sakuraia, T. Akitaa, S. Tsubota, M. Kiuchia and M. Haruta, Applied Catalysis A (2005), in press 5. S. Eriksson, U. Nylén, S. Rojas and M. Boutonnet, Applied Catalysis A 265 (2004) 207-219. 6. K. Yu, C. Yeung, D. Thompsett, and S. Tsang, J. Phys. Chem. B 107 (2003) 4515-4526
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