First principles investigation of adsorption and dissociation of AsH3 and H2Se on Zn2TiO4 (010) surface

CATL 9

Shiqiang Hao, shiqiang@andrew.cmu.edu1, David Sholl, sholl@andrew.cmu.edu1, and J. Karl Johnson, karlj@pitt.edu2. (1) Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, (2) Department of Chemical and Petroleum Engineering, University of Pittsburgh, 1242 Benedum Hall, Pittsburgh, PA 15261
Removal of corrosive or toxic species such as As, Se, and S is critical to the successful implementation of high efficiency Integrated Gasification Combined Cycle (IGCC) processes to utilize coal as a more efficient and environmentally friendly fuel. In this work we study the mechanism of the uptake of AsH3 and H2Se in a regenerable sorbent, zinc orthotitanate (Zn2TiO4), using first principles density functional theory. The AsH3 species adsorbs more strongly on oxygen-rich surfaces while the H2Se is more favorably bound to the metal-rich (010) surface. Further investigation of the dissociation barriers and corresponding dissociation rates shows that dehydrogenation should be facile at a typical experimental temperature of 823 K. For H2Se, the adsorption and dissociation behavior is not affected by surface Zn vacancy induced at experimental oxygen-rich conditions.
 

Nanotechnology in Catalysis V
1:30 PM-4:50 PM, Sunday, August 19, 2007 BCEC -- 261, Oral

Catalysis & Surface Science Secretariat

The 234th ACS National Meeting, Boston, MA, August 19-23, 2007