resumo
A novel approach to designing nitric oxide (NO) storage and releasing microporous agents based on very stable, zeolite-type silicates possessing framework unsaturated transition-metal centers has been proposed. This idea has been illustrated with ETS-4 [Na(9)Si(12)Ti(5)O(38)(OH)center dot xH(2)O], a titanosilicate that displays excellent NO adsorption capacity and a slow releasing kinetics. The performance of these materials has been compared to the performance of titanosilicate ETS-10, [(Na,K)(2)Si(5)TiO(13)center dot xH(2)O], of benchmark zeolites mordenite and CaA, and of natural and pillared clays. DFT periodic calculations have shown that the presence of water in the pores of ETS-4 promotes the NO adsorption at the unsaturated (pentacoordinated) Ti(4+) framework ions.
palavras-chave
TOTAL-ENERGY CALCULATIONS; ALUMINUM-PILLARED CLAYS; AUGMENTED-WAVE METHOD; ION-EXCHANGED ZSM-5; NITRIC-OXIDE; BASIS-SET; NITROGEN MONOXIDE; ADSORPTION; ZEOLITES; SILICATES
categoria
Chemistry
autores
Pinto, ML; Rocha, J; Gomes, JRB; Pires, J
nossos autores
Grupos
1 - Nanomateriais inorgânicos funcionais e híbridos orgânico-inorgânico
6 - simulação computacional e modelação multi-escala
Projectos
Nanostructured Photoluminescent rare-earth nanotubes and microporous silicates (PTDC/CTM/73243/2006)
agradecimentos
We acknowledge FEDER, FSE, and FCT for a postdoctoral grant (BPD/26559/2006), for the project PTDC/CTM/73243/2006, and for the Programa Ciencia 2007.