Photo Catalytic

7/24/2019 Photo Catalytic

1/13

PHOTOCATALYSTNguyen Thi Dieu Thuy, Chonbuk National University

October , 2015

1


2/13

1) Photocatalys

2) Nanoparticles necessary for

photocatalyst with high activity

2

CONTEXT


3/13

3

Chlorophyll of plants is a

typical natural photocatalyst.

Chlorophyll captures sunlight

to turn water and carbondioxide into oxygen and

glucose.

In the presence of light and water,

Photocatalyst creates strong

oxidation agent and electronic

holes to breadown the organic

!atter to carbon dioxide and water

1. Photocatalyst

A photocatalyst is a substance that useslight energytofacilitate a

chemical reaction.


4/13

4

Mechanism o !hotocatalysis

This cycle continues when light

is available.


5/13

5

Basic Functions of Photocatalyst

a" #terili$ing %ect

Photocatalyst does not only ill bacteria cells, but also deco!pose thecell itself.

"he titaniu! dioxide photocatalyst has been found to be !ore effective

than any other antibacterial agent, because the photocatalytic reaction

wors even when there are cells covering the surface and while the

bacteria are actively propagating.


6/13

6

b. Deodorizing effect

"he hydroxyl radicals accelerate the breadown of

any #olatile $rganic Co!pounds by destroying the

!olecular bonds.

"his will help co!bine the organic gases to for! a

single !olecule that is not har!ful to hu!ans thus

enhance the air cleaning efficiency.

Basic Functions of Photocatalyst


7/13

7Applications of photocatalyst air purification

c. Air Purifying Effect


8/13

8

d. Anti fogging, Self-Cleaning

%hen the original building !aterials are coated with a photocatalyst, a

protective fil! of titaniu! provides the self&cleaning building by beco!ing

antistatic, super oxidative, and hydrophilic.


9/13

9

e. Water Purification

Photocatalyst coupled with UV lights can oxidize organic

pollutants into nontoxic materials, such as CO2 and water and

can disinfect certain bacteria.

This technology is very effective at removing further hazardous

organic compounds (TOCs) and at killing a variety of bacteria

and some viruses in the secondary wastewater treatment.


10/13

10

Degradation of Dyes using TiO2


11/13

11

TiO2 Degrading Methylene Blue

0 10 20 30 40 50 60 70

1

1.1

1.2

1.3

1.4

1.5

1.6

Absorbance s. T ime

Time (mins)

Absorbance


12/13

12

2. Nanoparticles necessary for photocatalyst with high activity

Quantum size efects on the nanoparticles properties. Thus byvarying the size o the semiconductor particles, it is possible toenhance the redox potential o the valence-band holes and theconduction band electrons.

Small size

The big surace area

Shape and size o

interactive surace

Adsorption potential

A goodphotocatalyst

ith highactivity


13/13

13

THANK YOU

FORYOUR

ATTENTION

Documents

Photo Catalytic