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2018/07/12─Advanced Course in Environmental Catalytic Chemistry 1

July 12, 2018

12

Advanced Course in Environmental Catalytic Reaction Chemistry I 2

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 201808:45─10:15, Thursday at Lecture Room D103

Bunsho Ohtani (Ewa Kowalska/Mai Takashima)

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

[email protected]://pcat.cat.hokudai.ac.jp/pcat


objectives/goal/keywords

objectivesUnderstanding the mechanism of decomposition of pollutants, methods of photocatalysts preparation, design of practical photocatalytic reaction systems, and strategy for enhancement of photocatalytic activity.

goalTo understand principle of photocatalytic reaction from the standpoint of chemistry and strategy for practical applications. To obtain scientific method for research on functional solid materials.

keywordsPhotocatalyst, Photoinduced oxidative decomposition, Superhydrophilicity, Excited electron-positive hole, Structure-activity correlation, Higher photocatalytic activity, Visible-light response


schedule

(1) April 12 introduction of photocatalysis(2) April 19 interaction between substances and light(3) April 26 electronic structure and photoabsorption(4) May 10 thermodynamics: electron and positive hole

May 17 (no class)(5) May 24 adsorption(6) May 31 kinetic analysis of photocatalysis(7) June 7 steady-state approximation(8) June 14 artificial photosynthesis (Professor Mai Takashima)(9) June 21 kinetics and photocatalytic activity(10) June 28 action spectrum analysis (1)(11) July 5 action spectrum analysis (2)(12) July 12 crystal structure(13) July 19 design and development of photocatalysts(14) July 26 summary: photocatalysis A--Z (※questionnaire survey)(15) August 2 environmental application of photocatalysis (Professor

Ewa Kowalska)


comments on this lecture

Please send email in Japanese or English within 48 hours

to: [email protected]: pc2018MMDD-XXXXXXXX

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


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special report

special report for extra (bonus) score (20 point)report on critical review on "photocatalysis" in Wikipedia, pointing out errors, misunderstanding and speculationsbased on the contents of this lecture.http://en.wikipedia.org/wiki/Photocatalysishttp://ja.wikipedia.org/wiki/光触媒

• Japanese or English• A4 size 2 pages• submission by email attachment• a PDF file is more preferable than a Word file• email title: pc20180727-XXXXXXXX• file name: pc20180727-XXXXXXXX.pdf (or .docx or .doc)• deadline of submission: July 27, 2018 23:59

statistical analysis of photocatalytic activity 8

statistical multivariable analyses

to find out WHAT is/are the DECISIVE factor(s) for each reaction

by solving the matrix equation below to determine coefficients of each physical and structural properties

[rate]35×1 = [property]35×6 × [coefficient]6×1

rates and properties, were standardized using mean of data and standard deviation in order to make the calculated coefficients have the same weight being independent of properties, i.e., enabling direct comparison of partial regression coefficients (k).


statistical multivariable analyses

anatase/rutilesecondary particle sizedensity of defects

(a) 4Ag+ + 2H2O = 4Ag + O2 + 4H+

(b) CH3OH = HCHO + H2(c) CH3COOH + 2O2 = 2CO2 + 2H2O(d) CH3CHO + 5/2O2 = 2CO2 + 2H2O(e) L-lysine = PCA + NH3


anatase and rutile

• Activity decreases when anatase is transformed into rutile by high temperature calcination.

• possible reasons:(1) higher activity of anatase compared with that of rutile(2) decrease in specific surface area

dehydrogenation of 2-propanol（←）S.-i. Nishimoto, B. Ohtani, A. Sakamoto, T. Kagiya, Nippon Kagaku Kaishi 1984, 246.（↑）S.-i. Nishimoto, B. Ohtani, H. Kajiwara, T. Kagiya, J. Chem. Soc., Faraday Trans. 1 1985, 81, 61.

from titanium(IV) sulfate

from titanium(IV) tetra-2-propoxide


unit cell of crystal

• unit of repetition: connected to all directions• Atoms (ions) are shown in a dot at their center• Apexes are occupied by atoms (ions), which are shared by unit

cells.

• x-y-z (a-b-c) is set as a right hand.

b a

c α β

γ


1

1

1

2

two-dimensional unit cells


two-dimensional unit cells

2

2


unit cell of rutile

xyz is as a right-handedx: thumby: index fingerz: mid finger

An order of xyz is decided from same length.

Miller index: William Hallowes Miller

unit cell of rutile

black: Tiwhite: O

A AB

BC C

E F

GH

OJ

KL

y

x

z

b(y =1)

a(x =1)

c(z =1)


crystal structure of anatase (1)

red： Ogreen: Ti

0.9514 nm

0.3785 nm


crystal structure of anatase (2)

Q How many TiO2s are included in a unit cell?

A 1 + 4(1/2) + 8(1/8) = 4 <4TiO2>

Octahedron in anatase isa little skewed.


octahedron as a basic unit of titania crystals

QWhy do all the crystal structures of titania consist of octahedrons?


comments on this lecture

Please send email in Japanese or English within 48 hoursto: [email protected]: pc20180712-XXXXXXXX

[email protected]<full name><nickname><comments on this lecture><question(s) if any>


to: [email protected]

subject: pc20180712-12345678

pc20180712-12345678

[email protected]

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