2004 Fiscal Year Final Research Report Summary
Preparation of novel protonated forms of the ion-exchangeable layered perovskite via selective reaching of bismuth oxide sheets and their application to photocatalytic activities
| Project/Area Number |
14350462
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
無機工業化学
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| Research Institution | Waseda University |
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Principal Investigator |
SUGAHARA Yoshiyuki Waseda University, Faculty of Science and Engineering, Professor, 理工学術院, 教授 (50196698)
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| Co-Investigator(Kenkyū-buntansha) |
YASUMORI Atsuo Tokyo University of Science, Faculty of Industrial Science and Technology, Professor, 基礎工学部, 教授 (40182349)
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| Project Period (FY) |
2002 – 2004
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| Keywords | layered compound / ion-exchange / photocatalyst / selective leaching / perovskite / intercalation / surface modification |
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| Research Abstract |
Photocatalytic activities of the protonated forms of ion-exchangeable layered perovskites.
We investigated the photocatalytic activities of the Aurivillius phases Bi_2ANaNb_3O_<12> (A=Ca or Sr,Bi_2CaNaTa_3O_<12> and the protonated forms of ion-exchangeable layered perovskite prepared from these Aurivillius phases via selective leaching of bismuth oxide sheets by acid treatment. Photocatalytic activities were estimated based on H_2 evolution behavior from aqueous ethanol solutions (containing 20% ethanol) under UV irradiation. Aurivillius phases showed no activities for H_2 evolution, while the protonated forms exhibited the photocatalytic activities. UV-Vis diffuse reflectancee spectra indicated that selective leaching of bismuth oxide sheets led to the change in electric structure. XRD patterns of the protonated forms after H_2 evolution showed the increase in the interlayer distance, indicating the effective use of the interlayer space during H_2 evolution. Therefore, the difference i
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n the photocatalytic activity behavior between the Aurivillius phases and the protonated forms is attributable to the change in the position of the bottom of the conduction bands and/or the increases in surface area caused by the selective leaching of bismuth oxide sheets.
Preparation of novel double-layered tungstic acid.
We conducted acid treatment of an Aurivillius phase, Bi_2W_2O_9, whose structure was similar to that of ion-exchangeable layered perovskite. XRD,ICP and TG analyses as well as TEM observation showed the selective leaching of the bismuth oxide sheets, indicating the formation of the novel tungstic acid, H_2W_2O_7・nH_2O, which could potentially exhibit the photocatalytic activities.
Reaction of the protonated forms of layered perovskite and alcohols.
Since the n-alcohol is generally used as a sacrificial reagent for photocatalytic H_2 evolution from water, we investigated the interaction between the protonated forms of ion-exchangeable layered perovskite HCa_2Nb_2O_<10>・xH_2O and n-alcohol. The reaction of HCa_2Nb_2O_<10>・xH_2O with n-alcohols led to the formation of alkoxy-derivatives of HCa_2Nb_2O_<10>・xH_2O.
To achieve high photocatalytic activities, we explored the new pillaring method using organic derivatives of layered perovskite. When we conducted the reaction of CH_2=CH(CH_2)_nO- derivatives (n=3,8) of HLaNb_2O_7・xH_2O with hydrochlorosilanes and oligosiloxanes, XRD,IR and NMR analyses showed the occurrence of hydrosilylation in the interlayer space, indicating that hydrosily lation is utilizable for pillaring. Less
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Research Products
(12 results)
