LAUSR

Modern technology for in situ closed-cell gas-flow allows reactions to be conducted at elevated temperatures and at gas pressures up to one atmosphere [1]. However, introducing water vapor into the cell at percentages above the ~2% possible with room-temperature air at 100% relative humidity (e.g. to mimic bench-top reaction conditions) remains challenging due to the impracticality of heating the gas feed lines into the cell that is necessary to prevent water condensation. Water-vapor experiments are being performed using as a trial specimen MgO nanoparticles (from burning MgO ribbon and collecting the smoke). MgO is a hygroscopic mineral that converts to Mg(OH)2 (brucite) when exposed to water. Because the MgO smoke nanoparticles form perfect cubes, it was hypothesized that they could serve as a sensitive indicator for the presence of water vapor in the closed-cell gas-reactor holder. In situ results will ultimately be correlated to similar experiments performed in an ex situ reactor to confirm the presence of H2O vapor in the cell. Results of preliminary experiments are described here.