Hong, SB Kim, SJ Uh, YS 2024-01-21T19:13:24Z 2024-01-21T19:13:24Z 2022-01-10 1996-09-26 0022-3654 https://pubs.kist.re.kr/handle/201004/144299 For the first time, the formation of paramagnetic defect centers in AlPO4 molecular sieves has been monitored by electron spin resonance (ESR) spectroscopy. Results from ESR measurements demonstrate that the structural defects in hydrated AlPO4-5 and VPI-5 molecular sieves change into paramagnetic defect centers when the molecular sieves are dehydroxylated under a high vacuum (similar to 10(-5) Torr) at 773 K. Adsorption of O-2 or NO on dehydroxylated molecular sieves causes an immediate loss of the ESR signals from paramagnetic defects. This suggests that the defect centers formed are F-type centers, which can serve as electron donors for electron-withdrawing adsorbates. English AMER CHEMICAL SOC CRYSTALLINE INORGANIC SOLIDS Fundamental defect centers in AlPO4-5 and VPI-5 molecular sieves Article 10.1021/jp961275x 1 JOURNAL OF PHYSICAL CHEMISTRY, v.100, no.39, pp.15923 - 15925 JOURNAL OF PHYSICAL CHEMISTRY 100 39 15923 15925 scie scopus A1996VK04600042 2-s2.0-0006460416 Chemistry, Physical Chemistry Article CRYSTALLINE INORGANIC SOLIDS