Influence of ionic strength on brookite content in sol-gel synthesized titanium dioxide before and after hydrothermal aging

CHED 452

Eric R. Anderson, ERAnders3877@winona.edu1, Sara L. Isley, isley@chem.umn.edu2, and R. Lee Penn, penn@chem.umn.edu2. (1) Department of Chemistry, University of Minnesota - Minneapolis, 139 Smith Hall, 207 Pleasant Street, SE, Minneapolis, MN 55455-0431, (2) Department of Chemistry, University of Minnesota, 139 Smith Hall, 207 Pleasant St. S.E, Minneapolis, MN 55455
Sol-gel synthesis of titanium dioxide typically results in mixtures anatase, brookite, and sometimes amorphous titania. Hydrothermal aging is commonly performed post-synthesis and results in larger, more crystalline titanium dioxide nanoparticles. This study investigates increasing ionic strength on phase composition of hydrothermally aged titanium dioxide. XRD coupled with Reitveld refinements systematically tracked the polymorph ratios and nanoparticle size. Results indicate that increasing ionic strength during hydrothermal aging had no effect on the relative brookite content. Presence of a chloride ion during sol-gel synthesis is known to increase the amorphous content in the product and influence brookite content after hydrothermal treatment. However, the addition of chloride to dialyzed sol-gel synthesized nanoparticle suspensions had no effect on the brookite content in hydrothermally treated products. Finally, the photocatalytic activity of titania samples with similar average particle size but different brookite to anatase ratios was compared. Data suggested that particles with higher brookite content were less photocatalytically active.

 

Undergraduate Research Poster Session: Nanotechnology
11:00 AM-1:00 PM, Monday, March 26, 2007 Hyatt Regency Chicago -- Riverside Center, Poster

Division of Chemical Education

The 233rd ACS National Meeting, Chicago, IL, March 25-29, 2007