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Electroparamagnetic study of Mo(V) ion species incorporated into aluminosilicate nanospheres with solid core/mesoporous shell structure

2009년 8월 14일 16시 02분 28초
33P79포 이곳을 클릭하시면 발표코드에 대한 설명을 보실 수 있습니다.
금 <발표Ⅲ>
저자 및
백건호, 유종성1
창원대학교 화학과, Korea
1고려대학교 신소재화학과, Korea
Silica spheres with sub-micrometer sized solid core and mesoporous shell (SCMS) structure were synthesized, and aluminum was incorporated into the mesoporous shell framework by impregnation method to generate SCMS aluminosilicate (AlSCMS) nanospheres. The impregnation of aluminum into the SCMS spheres generates the acid sites on the framework due to the presence of Al3+ ions. The AlSCMS was then used to support molybdenum ion species on the mesoporous shell framework. A solid-state reaction of MoO3 with AlSCMS followed by thermal reduction generated paramagnetic Mo(V) species. The dehydration produced a Mo(V) species that is characterized by electron spin resonance with g e > g ⊥ > g ||. The structural properties of active sites in the AlSCMS were characterized by means of XRD, UV–Vis, 27Al MAS NMR, FT-IR, and energy dispersive X-ray spectrometric measurements. Upon O2 adsorption, the Mo(V) ESR signal intensity decreased, and a new O2 − radical was generated. The Mo species in the dehydrated Mo-AlSCMS is found to exist as oxo-molybdenum species, (MoO2)+ or (MoO)3+. Since the AlSCMS has a low framework negative charge, the MoO2 + with a low positive charge can be easily stabilized and thus seems to be more probable in the AlSCMS framework.