Hydrogen Production from Methanol or Methane by the Use of Thermally Generated Holes in TiO2

Matsumoto, Keiji; Satō, Yoshiyuki; Ebara, Toru; Mizuguchi, Jin

doi:10.1252/jcej.07we234

Cited by 15 publications

(10 citation statements)

References 9 publications

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“…4) Also note that the specific surface of Cr 2 O 3þx is only about 3 m 2 /g, whereas that of powdered TiO 2 of ST-01 is about 298 m 2 /g. [3][4][5][6][7] As is well-known, the specific surface plays an important role in the catalytic reaction, the present result clearly indicates that Cr 2 O 3þx is a superior material for VOC decomposition to TiO 2 . At the same time, the decomposition reaction has been confirmed to proceed continuously while both electrons and holes are consumed simultaneously at the band edge by maintaining the electrical neutrality.…”

Section: Resultssupporting

confidence: 62%

“…Consequently, VOC causes serious environmental issues such as sick house syndrome, photochemical smog, etc. 1) In view of the present situation, we started our investigation on complete removal of VOC and organic wastes utilizing thermally excited holes in oxide semiconductors, for example, TiO 2 at about 350-500 C. [2][3][4][5][6][7][8][9][10] The present technology dates back to our accidental finding that the catalytic effect will appear when oxide semiconductors are heated at high temperatures of about C. This is due to the formation of a large number of holes caused by thermal excitation of semiconductors. Lasers, transistors, and diodes are the representative applications of semiconductors; whereas ours is the application which utilizes semiconductive properties at high temperatures.…”

Section: Introductionmentioning

confidence: 99%

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Thermally Activated Cr2O3+x for Elimination of Volatile Organic Compounds

2010

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We have previously shown that oxide semiconductors (for example, TiO 2 , NiO, etc.) exhibit significant catalytic effects when heated at about 350-500C. This is due to the formation of a vast number of highly oxidative holes at high temperatures. Then, we applied the present finding for complete removal of volatile organic compounds (VOCs). In the present investigation, we focused on Cr 2 O 3þx (0 < x < 1) in an attempt to lower the operation temperature of VOC decomposition. We present here how the low-temperature operation proceeds with Cr 2 O 3þx and also elucidate why Cr 2 O 3þx is colored green, on the basis of the temperature dependences of electrical conductivity and Seebeck potential of Cr 2 O 3þx . The green color of Cr 2 O 3þx is found to arise from Cr vacancies in Cr 2 O 3þx , and the vacancies are responsible for the formation of a narrow conduction band or a deep acceptor level, resulting in the low-temperature operation of VOC decomposition.

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Section: Resultssupporting

confidence: 62%

Section: Introductionmentioning

confidence: 99%

Thermally Activated Cr2O3+x for Elimination of Volatile Organic Compounds

2010

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“…1) In view of the present situation, we started our investigation on complete removal of VOC and organic wastes by means of thermally excited holes in oxide semiconductors such as TiO 2 , [4][5][6][7][8][9][10][11][12][13] NiO, 14) Cr 2 O 3 15,16) and -Fe 2 O 3 17) at about 350-500 C. The use of thermally generated holes for removal of VOC and organic wastes is an entirely new technology initiated by us in 2001.…”

Section: Introductionmentioning

confidence: 99%

VOC Decomposition System Based upon Heater-Integrated Catalyst Units Using NiO or Cr2O3

Maki

Mizuguchi

2010

Mater. Trans.

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We have previously shown that oxide semiconductors (TiO 2 , NiO, Cr 2 O 3 , etc.) exhibit remarkable catalytic effects when heated at high temperatures of about 350-500 C and that the effect has been interpreted in terms of the formation of a large number of highly oxidative holes caused by thermal excitation of semiconductors. This prompted us to utilize this technology for complete removal of volatile organic compounds (VOCs). In the present investigation, we aim at constructing a compact device for practical implementation composed of four-stacked ''heater/ honeycomb'' units. Each unit comprises a spiral Ni-Cr heater as well as a honeycomb plate coated with powdered NiO or Cr 2 O 3 . Decomposition experiment was carried out in the range from room temperature to 500 C, using 10000 ppm toluene as the VOC at a flow rate of 10 l/min. As a result, the toluene decomposition was found to begin at about 100 C and was completed (i.e., 0 ppm) at about 300 C, showing an excellent decomposition characteristic in both NiO and Cr 2 O 3 .

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“…[6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] This novel technology developed by us has mainly been used for complete decomposition of thermoplastic or thermosetting polymers, as well as volatile organic compounds (VOCs). However, this technology has never been tested so far for the recovery of glass fibers from FRPs.…”

Section: Introductionmentioning

confidence: 99%

Recovery of Glass Fibers from Fiber Reinforced Plastics

2011

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Recovery of glass fibers from fiber reinforced plastics (FRP) has been tackled by our novel technology based upon thermally activated semiconductors such as Cr 2 O 3 , NiO, TiO 2 , and -Fe 2 O 3 . This is a scientifically proven technology which utilizes a vast number of thermallygenerated oxidative holes for instantaneous decomposition of filler-free thermoplastic or thermosetting polymers. No shredding or grinding of the scrap FRP is necessary in the present system, nor is the use of organic solvents. FRP plates were simply placed in contact with powdered Cr 2 O 3 and heated at about 350-500 C. As soon as the FRP was sufficiently heated, the polymer matrix began to decompose into H 2 O and CO 2 , leaving behind only glass fibers without any deterioration of their quality. The glass fibers were perfectly recovered, exactly in the original form of ''chopped strand mat''. Our system can recover glass fibers as well as thermal energy.

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Hydrogen Production from Methanol or Methane by the Use of Thermally Generated Holes in TiO2

Cited by 15 publications

References 9 publications

Thermally Activated Cr<SUB>2</SUB>O<SUB>3+<I>x</I></SUB> for Elimination of Volatile Organic Compounds

Thermally Activated Cr<SUB>2</SUB>O<SUB>3+<I>x</I></SUB> for Elimination of Volatile Organic Compounds

VOC Decomposition System Based upon Heater-Integrated Catalyst Units Using NiO or Cr<SUB>2</SUB>O<SUB>3</SUB>

Recovery of Glass Fibers from Fiber Reinforced Plastics

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