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PHOTOCATALYTIC DECOMPOSITION OF N2O AND CU+/Y-ZEOLITE CATALYSTS PREPARED BY ION - EXCHANGE
Anpo, Masakazu,Matsuoka, Masaya,Hano, Kanami,Mishima, Hirotsugu,Ono, Takehiko,Yamashita, Hiromi 한국화학공학회 1997 Korean Journal of Chemical Engineering Vol.14 No.6
In situ characterization of Cu^+/Y-zeolite catalysts and their photocatalytic reactivities for the decomposition of N₂O into N₂and O₂have been investigated by means of in situ photoluminescence, XAFS, and ESR techniques along with an analysis of the reaction products. It was found that Cu(Ⅰ) ions included within the nanopores of Y-zeolite exist as the [Cu(Ⅰ)--Cu(Ⅰ)] dimer species as well as the isolated Cu(Ⅰ) monomer species, their ratio being much dependent on the SiO₂/Al₂O₃ratio of Y-zeolite. UV irradiation of these Cu^+/Y-zeolite catalysts in the presence of N₂O led to the photocatalytic decomposition of N₂O into N₂ and O₂at temperatures as low as 275 K. The electronically excited state of Cu(I) ion (3d^94s¹state) plays a vital role in the photocatalytic decomposition of N₂O into N₂and O₂. The photocatalytic reactivity of these Cu^+/zeolite catalysts was found to be strongly affected by the local structure of the Cu(Ⅰ) ions which could easily be modified by changing the SiO₂/Al₂O₃ratio of Y-zeolite. The isolated linear 2 coordinated Cu(Ⅰ) monomer species formed on Y-zeolite having a moderate SiO₂/Al₂O₃ratio exhibited a high photocatalytic reactivity for the direct decomposition of N₂O into N₂and O₂, clearly showing the importance of the coordinative unsaturation of the active sites.
Articles : Photocatalytic Decomposition of N2O on Cu(+)/Y-Zeolite Catalysts Prepared by Ion-Exchange
( Masakazu Anpo ),( Masaya Matsuoka ),( Kanami Hano ),( Hirotsugu Mishima ),( Takehiko Ono ),( Hiromi Yamashita ) 한국화학공학회 1997 Korean Journal of Chemical Engineering Vol.14 No.6
In situ characterization of Cu^+/Y-zeolite catalysts and their photocatalytic reactivities for the decomposition of N₂O into N₂and O₂have been investigated by means of in situ photoluminescence, XAFS, and ESR techniques along with an analysis of the reaction products. It was found that Cu(Ⅰ) ions included within the nanopores of Y-zeolite exist as the [Cu(Ⅰ)--Cu(Ⅰ)] dimer species as well as the isolated Cu(Ⅰ) monomer species, their ratio being much dependent on the SiO₂/Al₂O₃ratio of Y-zeolite. UV irradiation of these Cu^+/Y-zeolite catalysts in the presence of N₂O led to the photocatalytic decomposition of N₂O into N₂ and O₂at temperatures as low as 275 K. The electronically excited state of Cu(I) ion (3d^94s¹state) plays a vital role in the photocatalytic decomposition of N₂O into N₂and O₂. The photocatalytic reactivity of these Cu^+/zeolite catalysts was found to be strongly affected by the local structure of the Cu(Ⅰ) ions which could easily be modified by changing the SiO₂/Al₂O₃ratio of Y-zeolite. The isolated linear 2 coordinated Cu(Ⅰ) monomer species formed on Y-zeolite having a moderate SiO₂/Al₂O₃ratio exhibited a high photocatalytic reactivity for the direct decomposition of N₂O into N₂and O₂, clearly showing the importance of the coordinative unsaturation of the active sites.
Shul, Yong Gun,Yamashita, Hiromi,Anpo, Masakazu,Jung, Kyeong Taek 한국화학공학회 1997 Korean Journal of Chemical Engineering Vol.14 No.3
TS-1 zeolite film has been prepared by using nano sized TS-1 zeolite particles for the photocatalytic isomerization of cis-2-butene. TS-1 zeolite film showed optical transparent property and the thickness of film was 0.7 ㎛. UV irradiation of TS-1 zeolite film in the presence of cis-2-butene leads to the photocatalytic isomerization of cis-2-butene into trans-2-butene at the temperature of 275 K. The yield of trans-2-butene was linearly increased with UV-irradiation time.
박훈,HyunSeock Jie,채근화,박종구,Masakazu Anpo,Dok-Yol Lee 한국물리학회 2008 Current Applied Physics Vol.8 No.6
Anatase-type TiO₂ nanopowders less than 10 nm in average diameter were synthesized by a chemical vapor synthesis method. The TiO₂ nanopowders showed very poor photocatalytic properties, in spite of their large surface area. With subsequent heat treatment of the TiO₂ powders, their photocatalytic properties determined by measuring the degradation of 2-propanol were improved at temperatures up to 600˚C and then diminished along with formation of a rutile phase. This improvement in the photocatalytic properties of TiO₂ nanopowders was attributed to both a morphology change and a change in the electronic surface characteristics of TiO₂ particles during heat treatment. Anatase-type TiO₂ nanopowders less than 10 nm in average diameter were synthesized by a chemical vapor synthesis method. The TiO₂ nanopowders showed very poor photocatalytic properties, in spite of their large surface area. With subsequent heat treatment of the TiO₂ powders, their photocatalytic properties determined by measuring the degradation of 2-propanol were improved at temperatures up to 600˚C and then diminished along with formation of a rutile phase. This improvement in the photocatalytic properties of TiO₂ nanopowders was attributed to both a morphology change and a change in the electronic surface characteristics of TiO₂ particles during heat treatment.
( Kyeong Taek Jung ),( Yong Gun Shul ),( Masakazu Anpo ),( Hiromi Yamashita ) 한국화학공학회 1997 Korean Journal of Chemical Engineering Vol.14 No.3
TS-1 zeolite film has been prepared by using nano sized TS-1 zeolite particles for the photocatalytic isomerization of cis-2-butene. TS-1 zeolite film showed optical transparent property and the thickness of film was 0.7 ㎛. UV irradiation of TS-1 zeolite film in the presence of cis-2-butene leads to the photocatalytic isomerization of cis-2-butene into trans-2-butene at the temperature of 275 K. The yield of trans-2-butene was linearly increased with UV-irradiation time.
Jie, HyunSeock,Park, Hoon,Chae, Keun-Hwa,Anpo, Masakazu,Park, Jong-Ku Elsevier 2009 Chemical physics letters Vol.470 No.4
<P><B>Graphical abstract</B></P><P>The variation of relative peak area between t<SUB>2g</SUB> and e<SUB>g</SUB> at each irradiation condition.</P><ce:figure></ce:figure> <P><B>Abstract</B></P><P>An in-situ NEXAFS study was performed to directly investigate the change in the hole structures in the conduction band of TiO<SUB>2</SUB> nanopowders synthesized using a flame method under UV irradiation. The anatase/rutile phase boundary was found to suppress the hole–electron recombination, leading to improved photoreactivity of TiO<SUB>2</SUB> nanopowders.</P>
Photocatalytic Decomposition of NO on Transition Metal Ion-exchanged Zeolite Catalysts
Shul, Yong Gun,Park, Sang Eon,Yamashita, Hiromi,Anpo, Masakazu,Matsuoka, Masaya,Ju, Woo Sung 한국공업화학회 2000 Journal of Industrial and Engineering Chemistry Vol.6 No.3
Transition metal ions (Cu^+, Ag^+) incorporated within the cavities of zeolites by an ion-exchange method show an efficient and unique photocatalytic performance for the decomposition of NO into N₂ and O₂ at 275 K. In situ ESR, UV-VIS, photoluminescence and XAFS (XANES and FT-EXAFS) investigations revealed that the transition metal ions exist in highly dispersed state with linear 2 coordination sphere within the pores of zeolites, the local structures of the metal ions being significantly affected by changing the kinds of zeolites. Detailed studies of the interaction of NO with the excited states of these metal ions clearly indicated that unique inner shell type excitation states of these metal ions play a significant role in the photocatalytic decomposition of NO, i.e., an electron transfer from the s orbital of the excited state of Cu^+ or Ag^+ ions into the π^* antibonding orbital of NO initiates the decomposition reaction of NO.
Shul, Yong Gun,Park, Sang Eon,Yamashita, Hiromi,Anpo, Masakazu,Matsuoka, Masaya,Park, Dal Ryung 한국공업화학회 2000 Journal of Industrial and Engineering Chemistry Vol.6 No.2
Titanium or vanadium oxide species incorporated within the framework of zeolites or mesoporous molecular sieves by an ion-exchange method or hydrothermal synthesis show high and unique photocatalytic activities for various reactions such as the decomposition of NO into O_2 or the reduction activities of CO_2 with H_2O to produce CH_4 and CH_3OH. In situ photoluminescence, XAFS and ESR investigations revealed that titanium as well as vanadium oxide moieties exist in highly dispersed tetrahedral coordination states in the zeolite framework and the charge transfer excited state of these transition metal oxide species play a vital role in the photocatalytic reactions on these zeolite and molecular sieve catalysts. The unique physicochemical properties of porous materials such as pore size, channel structural dimensions, and distribution of ion-exchangeable sites are shown to be important factors in controlling the dispersion and local structures of the metal oxides incorporated within such porous materials as well as the photocatalytic reactivities and selectivities in various photocatalytic reactions.
Hoon Park,Bernaurdshaw Neppolian,Hyun Seock Jie,안재평,박종구,Masakazu Anpo,이덕열 한국물리학회 2007 Current Applied Physics Vol.7 No.2
2 photocatalysts (FeZnTiO2) prepared by a ame method showed high photocatalytic activity for the deg-radation of 2-propanol dissolved in water as compared with mono-metal incorporated or unincorporated TiO2. By using this amemethod, parameters such as uniform particle size, crystallinity as well as the anatase and rutile phase ratio (anatase/rutile) could be con-trolled without calcination of the catalysts at high temperatures, the parameters being important to achieve a high photocatalytic activity.and uniform size particles with dened anatase/rutile pha se ratio of around 60/40, this being similar to that of P-25 which is well knownas a highly active photocatalyst.