CHEMISTRY OF SO2 AND DESOX PROCESSES ON OXIDE NANOPARTICLES.

RODRIGUEZ, J.A.

Brookhaven National Laboratory

关键词: Nanostructures;    Dissociation;    Calcium Oxides;    Sulfur Dioxide;    Vacancies;   

DOI  :  10.2172/893860
RP-ID  :  BNL--76856-2006-BC
RP-ID  :  DE-AC02-98CH10886
RP-ID  :  893860

美国|英语

来源: UNT Digital Library

【 摘 要 】

On bulk stoichiometric oxides, SO{sub 2} mainly reacts with the O centers to form SO{sub 3} or SO{sub 4} species that decompose at elevated temperatures. Adsorption on the metal cations occurs below 300 K and does not lead to cleavage of the S-O bonds. In bulk oxides, the occupied cation bands are too stable for effective bonding interactions with the LUMO of SO{sub 2}. The effects of quantum confinement on the electronic properties of oxide nanoparticles and the structural defects that usually accompany these systems in general favor the bonding and dissociation of SO{sub 2}. Thus, nanoparticles of MgO, CaO, SrO, Al{sub 2}O{sub 3}, Fe{sub 2}O{sub 3} and CeO{sub 2} are all more efficient for sequestering SO{sub 2} than the corresponding bulk oxides. Structural imperfections in pure or metal-doped ceria nanoparticles accelerate the reduction of SO{sub 2} by CO by facilitating the formation and migration of O vacancies in the oxide surface.