20150409 bo sapporo - 北海道大学pcat.cat.hokudai.ac.jp/class/pc2015/20150409_bo_sapporo.pdf ·...

2015/04/09—Advanced Course in Environmental Catalytic Chemistry 1

2015/04/09

introduction of Professor Ohtani Laboratory


Advanced Course in Environmental Catalytic Chemistry I

understanding chemistry by understanding photocatalysisunderstanding photocatalysis by understanding chemistry

Division of Environmental Material Science, Graduate School of Environmental ScienceThe first semester of Fiscal 201508:45─10:15, Thursday at Lecture Room D103

Bunsho Ohtani and Ewa Kowalska

Catalysis Research Center, Hokkaido University, Sapporo 001-0021, Japan011-706-9132 (dial-in)/011-706-9133 (facsimile)

[email protected]://www.hucc.hokudai.ac.jp/~k15391/


objectives/goal/keywords

<< objectives >>Understanding the mechanism of decomposition of pollutants, methodsof photocatalysts preparation, design of practical photocatalytic reactionsystems, and strategy for enhancement of photocatalytic activity.

<< goal >>To understand principle of photocatalytic reaction from the standpointof chemistry and strategy for practical applications. To obtain scientificmethod for research on functional solid materials.

<< keywords >>Photocatalyst, Photoinduced oxidative decomposition, Superhydro-philicity, Excited electron-positive hole, Structure-activity correlation,Higher photocatalytic activity, Visible-light response


schedule

(1) Apr 9 introduction of photocatalysis(2) Apr 16 interaction between substances and light(3) Apr 23 electronic structure and photoabsorption(4) Apr 30 thermodynamics: electron and positive hole(5) May 7 adsorption(6) May 14 kinetic analysis of photocatalysis(7) May 21 steady-state approximation(8) May 28 (Environmental application of photocatalysis) Kowalska(9) Jun 4 kinetics and photocatalytic activity(10) Jun 11 action spectrum analysis (1)(11) Jun 18 action spectrum analysis (2)(12) Jun 25 crystal structure (1)(13) Jul 2 crystal structure (2)(14) Jul 9 design and development of photocatalysts (1)(15) Jul 16 design and development of photocatalysts (2)


comments on this lecture

Please send email in Japanese or English within 48 hours

to: [email protected]: pc2015MMDD-XXXXXXXX

[email protected](full name)(nickname)(comments and/or questions on today's lecture)


questions

Q Have you heard or seen a term "photocatalysis" (or "photocatalyst") before attending this class?

Q Do you know the examples of practical applications of photocatalysis? Interpret the mechanism.

Q What is the meaning of "catalyst (or catalysis)" in a term "photocatalyst"?

introduction of photocatalysis

introduction 8

Hokkaido University: A National University

Hokkaido: A northern island of JapanSapporo: A capital city of Hokkaido

Prefecture

introduction 9

introduction 10

Catalysis Research Center, Hokkaido Univ.

Catalysis Research Center

Unique research institute for studies on catalysis, including photocatalysis, in Japan, previously "Institute for Catalysis".Twenty faculty members including nine full professors.

introduction 11

Catalysis Research Center (CRC)

Catalysis Research Center (CRC) originate from Institute for Catalysiswhich was founded in 1943 in Hokkaido University for fundamental studieson catalysis, and started as a national collaborating institution in 1988,followed by scale-up reorganization in 1998 and by reorganization renewalin 2007 for playing a leading role in catalysis studies and a bridging roleamong interdisciplinary research fields.

introduction 12

Catalysis Research Center

9 Professors (K. Asakura/M. Osawa/B. Ohtani/W. Ueda/A. Fukuoka/T. Takahashi/T. Nakano/J. Hasegawa/M. Nishida)

9 Associate professors 8 Assistant professors

Research fellowsVisiting professorsCollaborative researchersStudentsTentative staffTechnical staffAdministrative staff

introduction 13

CRC: Divisions and Clusters

Target-Oriented R

esearch Assem

bly

Professor Associate Professor

触媒理論化学研究部門

Fundamental Research Division

実用化基盤技術開発部

コーポレートユニット

introduction 14

2010 Nobel Prize in Chemistry

Professor Akira SUZUKI (Professor Emeritus, Hokkaido University)

Professor Ei-ichi NEGISHI(Purdue University)

These two professors are also Specially Invited Professors in Catalysis Research Center, Hokkaido University

introduction 15

titania-coated glass of our building

• all glass plates are coated with titania to reduce infrared radiation (with expectation to keep the surfaces clean).

• coated on site; not construction with pre-coated glass plates• expected photocatalytic self-cleaning effect

introduction 16

to be a world number one labo on photocatalysis

photocatalysis

URL of web page for Professor Ohtani Laboratoryhttp://www.hucc.hokudai.ac.jp/~k15391/

光触媒研究室検索

"photocatalysis" and "laboratory"

introduction 17

Ohtani Laboratory for photocatalysis research

collaboration work using advanced instruments designed for photocatalysis research

evaluation of photocatalytic activities

education for young people

opened for researchers in academics and industries

introduction 18

single-author books

Hikarishokubai no Shikumi ga Wakaru HonHikarishokubai Hyojun Kenkyuho (Scientific Methods in Photocatalysis)

introduction 19

recent critical reviews (not compilations)

• Ohtani, B. (2014) Revisiting the Original Works Related to Titania Photocatalysis: A Review on Papers in the Early Stage of Photocatalysis Studies. Electrochemistry, in press .

• Ohtani, B. (2014) Revisiting the Fundamental Physical Chemistry in Heterogeneous Photocatalysis: Its Thermodynamics and Kinetics. Phys. Chem. Chem. Phys., 16 (5), 1788 -1797.

• Ohtani, B. (2013) Titania Photocatalysis Beyond Recombination: A Critical Review. Catalysts, 3 (4), 942-953.

• Ohtani, B. (2013) Design and Development of Active Titania and Related Photocatalysts. Photocatalysis and Water Purification: From Fundamentals to Recent Application, P. Pichat ed. Photocatalysis and Water Purification: From Fundamentals to Recent Application, Wiley-VCH Verlag, 75-102.

• Ohtani, B. (2010) Photocatalysis A to Z―What We Know and What We Don't Know. J. Photochem. Photobiol. C Photochem. Rev., 11 (4), 157-178.

• Ohtani, B. (2008) Preparing Articles on Photocatalysis―Beyond The Illusions, Misconceptions and Speculation. Chem. Lett., 37 (3), 216-229.

introduction 20

critical reviews

critical reviews on, not a compilation of, photocatalytic studies

Open paper: free of charge for downloading the PDF file

introduction 21

Professor Ken-ichi Fukui

October 19, 1981: announcement of Nobel Prize in ChemistryJanuary 9, 1998: died


practical applications

Q Which application impressed you the most? What is the reason for that?

Q What is the general chemical reaction(s) included in the practical applications of photocatalysis? Show a reaction formula(s).


photocatalysis: two major phenomena

photocatalytic decompositiontarget:

organic compoundssteins (oil)microorganisms

photoinduced (super) hydrophilicitywashable with running wateranti-fogging

mechanism


regular PVC Teflon-coated titania-coated

after exposure outdoor for 5 months

showing change in

color

Taiyo Kogyohttp://www.taiyokogyo.co.jp/

tent material coated with titania photocatalyst

PVC must contain organic additives, which go out to the surface slowly, to be elastic.


titania-coated glass of our building

• all glass plates are coated with titania to reduce infrared radiation (with expectation to keep the surfaces clean).

• coated on site; not construction with pre-coated glass plates• expected photocatalytic self-cleaning effect


substrate: steal plates

JFE Building Materialshttp://www.jfe-kenzai.co.jp/index.shtml

exterior materials coated with titania


with

paints requiring no heating: room-temperature coating

titania photocatalytic painting

painting procedure with brush or roller

painting procedure:spraying

withoutwith

without

with without


large-scale application of photocatalysts"self-cleaning" window glasses

"Marubiru", a large office building in Tokyo

"Centrea", Chubu International airport, Nagoya


inside: anti-fogging effect to give water droplet-free surfaceoutside: photocatalytic decomposition and (super) hydrophilicity to

keep the surface clean

photocatalyst coated glass

Japan Hydrotect Coatings

regular glass

titania-coated glass

on-site coating > pre-coating


Nippon Sodahttp://www.nippon-soda.co.jp/photo/report.html

titania coatings with heating = pre-coating window blinds

titania photocatalyst-including paint

No effect of photo-induced hydrophilicity is expected for indoor use.


"partition" with photocatalytic coatings

possible effects:cleaning by decomposition of organic matters/deodorization/anti-microorganisms

Mitsubishi Plasticshttp://www.mpi.co.jp/press/pr030501.htm


titania-coatings for anti-fogging

TOTO

regularpart

titaniacoatedpart

no water droplets due to the (super) hydrophilicity of photocatalytic titania surface


polycarbonate plates covered withtitania photocatalyst on both sides

Sekisui Plasticshttp://www.sekisuijushi.co.jp/

road-side sound barriers coated with titania

titania1.5 year

regular1.5 year

regular3.5 year


pavements containing titania photocatalyst

"Photoroad"

Nitrogen oxides (NOx) are oxidized by photocatalystResulting nitrate (NO3

-) ions are captured by calcium ionsCalcium nitrate (Ca(NO3)2) is washed out by rain water

Fujitahttp://www.fujita.co.jp


Toshiba Lightechttp://www.tlt.co.jp/tlt/new/crean/crean.htm

a covering window glass coated with titania

lights for outdoor use

regularfluorescent lamp

lighting device with titania photocatalyst


photocatalytic air purifier unit

active air purification: decontamination and deodorization of circulating air

Hitachi Home and Life Solutionhttp://www.hitachi-hl.com/

Daikin Ltd.http://www.daikinaircon.com/

air conditioner

air purifier


photocatalytic treatment of water

Sumitomo Metal Industrieshttp://www.sumitomometals.co.jp/news/monthly/2001/140.html

polluted gas

drain

aeration unit

water

exhaust

pump

soil

groundwater

air

dryerseparator photocata-lyst

neutra-lizer

decontaminated

polluted gasblack light

flow apparatus

Contaminated ground water is treated to remove volatile organic compounds.


smoke cleaner/refrigerator

Toshiba/Mitsubishihttp://www.toshiba.co.jp/about/press/2001_09/pr_j0302.htmhttp://www.mitsubishielectric.co.jp/news/2009/0825-a.htm

deodorization/decomposition of ethylene (CH2=CH2) from vegetables/fruits to keep freshness


photocatalytic water treatment

photocatalytic fiber cartridge for decomposition of dioxin and sterilization

UBE Industrieshttp://www.ube-ind.co.jp/japanese/japanese/annai/01_05_03.htm

チタニアが有機物を酸化分解する光触媒機能に着目して、接触面積が大きく、丈夫な繊維状にしたのが『光触媒繊維』。既存の光触媒製品と差別化した製品の特色を活かして市場開発を進めています。この新素材はダイオキシンの分解にも期待されています。


a TOC analyzer with a photocatalytic reactor

Hiranuma Industrieshttp://www.hiranuma.com/products/envr/toc/

• Analyzing TOC (total organic carbon), organic compounds are decomposed by oxidantsinto carbon dioxide (CO2) and the amount of CO2 is measured.

• Conventional analyzers require the use of potassium permanganate as an oxidant or ofa expensive short-wavelength (254 nm) mercury arc lamp.

• Using a titanium(IV) oxide photocatalyst system, any chemicals and their posttreatment are not needed and cheaper long-wavelength mercury arc lamps can beused.

TOC-3000

TOC-2000


photocatalysis industries in Japanindustries related to photocatalysisalmost 300 million USD after 2005(Photocatalysis Industry Association of Japan)

otherslivingwarecleanuproadinteriorexteriorm

illio

n U

SD

400

300

200

100

02000 2002 2004 2006 2008


photocatalysis industries in Japan2012 (2011): ca. 400 million USD [370 million USD for 2011]

47(52)%

2(1)%

3(4)%

43(38)%

4(4)%

exterior

interiorroad related

purifier

living ware


photocatalysis: two major phenomena

superhydrophilicity: the surface of photocatalytic (titania) coatings becomes super hydrophilic, i.e., contact angle to be almost zero.

photocatalytic oxidation: organic and inorganic compounds are oxidized under air to be inorganic materials, i.e, mineralization.

left: photocatalytic/right: ordinary

mechanism


titanium(IV) oxide (titania) as a photocatalyst

no change after reaction = "catalyst"

no reaction in the dark = "safe" and environ-mentally benign

very popular and cheap material

especially strong oxidizing power when irradiated

white or colorless = no effect on appearancebut, requires ultraviolet irradiation

highphoto-

stability

superiorredox ability availability

notpoisonous& natural

titanium(IV) oxideTiO2

titania


comments on this lecture

Please send email in Japanese or English within 48 hoursto: [email protected]: pc2015MMDD-XXXXXXXX

[email protected] namenicknamecomments (questions) on this lectureorder of book(s) if any

JPY1,200 (77%) JPY3,500 (79%)


to: [email protected]

subject: pc20150409-12345678

pc20150409-12345678

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