oa Nanotechnology for Pollution Reduction

Nanotechnology is regarded as the next great scientific/industrial revolution due to the possibility of designing nanostructured materials that possess novel electronic, optical, magnetic, and catalytic properties. Nanomaterials could potentially be applied in pollution control, catalysis, water remediation, clean energy.

Nanocatalysis is a phenomenon of significant research and important practical applications in a variety of fields such as materials, environmental and atmospheric sciences. Low-temperature catalytic oxidation of carbon monoxide (CO) is one of the most important problems in pollution since even small exposures to CO (ppm) can be lethal. Nanophase metal and metal oxide catalysts, with controlled particle size, high surface area, and more densely populated unsaturated surface coordination sites, could potentially provide significantly improved catalytic performance over conventional catalysts. It is therefore, expected that nanoparticle catalysts would show high catalytic activity for the low temperature oxidation of CO than bulk materials.

Noble metals are well known oxidation catalysts with high activity and stability, even in the presence of moisture and sulfur compounds, and they are usually used in gas exhaust emissions control. The high cost of precious metals and their sensitivity to sulfur poisoning motivated re-searchers to search for new catalysts. Alloying is a phenomenon that can either improve the catalytic properties of the original single-metal catalysts for CO oxidation. Recently, we reported the effect of support on the catatalytic activity of Au catalyst.

We have prepared metallic and bimetallic nanocatalysts on different supports using differ-ent synthesis methods. The catalytic activity of each catalyst was carried out by using a flow tube reactor coupled to an infrared detector. Our results indicate that unsupported AuCu alloy shows higher activity than Au or Cu alone. These results attributed to the formation of CuO within the bimetallic nanoparticles, which improves the catalytic activity of Au-Cu alloy nanoparticle. On the other hand, Au nanoparticles supported on CeO2 exhibit higher catalytic activity than Cu, CuO, and AuCu alloy supported on CeO2. These results attributed to the strong interaction of Au with CeO2.