EMSL and Institute for Integrated Catalysis (IIC) Catalysis Workshop

Within the context of significantly accelerating scientific progress in research areas that address important societal problems, a workshop was held in November 2010 at EMSL to identify specific and topically important areas of research and capability needs in catalysis-related science

Exploration of Methods to Remove Implanted 210^{210}Pb and 210^{210}Po Contamination from Silicon Surfaces

Radioactive contaminants on the surfaces of detector components can be a problematic source of background events for physics experiments searching for rare processes. Exposure to radon is a specific concern because it can result in the relatively long-lived $^{210}$Pb (and progeny) being implanted to significant subsurface depths such that removal is challenging. In this article we present results from a broad exploration of cleaning treatments to remove implanted $^{210}$Pb and $^{210}$Po contamination from silicon, which is an important material used in several rare-event searches. We demonstrate for the first time that heat treatments ("baking") can effectively mitigate such surface contamination, with the results of a 1200 $^{\circ}$C bake consistent with perfect removal. We also report results using wet-chemistry and plasma-based methods, which show that etching can be highly effective provided the etch depth is sufficiently aggressive. Our survey of cleaning methods suggests consideration of multiple approaches during the different phases of detector construction to enable greater flexibility for efficient removal of $^{210}$Pb and $^{210}$Po surface contaminationComment: 8 pages, 7 figure

Direct Deoxygenation of Phenylmethanol to Methylbenzene and Benzyl Radicals on Rutile TiO₂(110)

Understanding the deoxygenation of biomass-derived alcohols is of great importance for the conversion of renewable biomass to energy carriers. In this work, we present unique reaction pathways for phenylmethanol on a rutile TiO₂(110) by using a combination of molecular beam dosing and temperature-programmed desorption. The results from both regular and OD-labeled phenylmethanol demonstrate that hydroxyl hydrogen is transferred to the benzyl group to yield methylbenzene between 300 and 480 K. In the competing reaction, the hydroxyl hydrogen is also converted to water in the same temperature range. Once the hydroxyl hydrogen is depleted above 480 K, the remaining phenylmethoxy surface species undergo C–O bond cleavage yielding gas-phase benzyl radical species. These findings reveal the formation of free radical species from the interaction of phenylmethanol with TiO₂(110) and demonstrate a direct mechanism for deoxygenation of lignin-derived benzylic alcohols to aromatics on TiO₂