Visible Light Semiconductor Photocatalysts

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Commercialisation of Chemistry
Visible light semiconductor
photocatalysts
– a novel hygiene solution
Declan McCormack (DIT) and Robert Hickson (Vitra)
Institute of Chemistry of Ireland – Annual Congress
Friday, 27th May 2011
Rev. No: C
Issue Date: 08/06/2010
Owner: B. Duffy
Titania (TiO2)
Nafion
Precipitation of submicron high surface area seconducting titania as a support
for metal oxide anodic catalysts, mainly for fuel cells.
Institute of Chemistry of Ireland Annual Congress
Friday, 27th May 2011
Rev. No: C
Issue Date: 08/06/2010
Owner: B. Duffy
Ignatz Semmelweis (1818-1865)
1847- Childbed (Puerperal) Fever in Vienna Hospital Obstetrical Clinic
First clinic
Year Births Deaths Rate (%)
Second clinic
Births Deaths Rate (%)
1841 3,036
237
7.8
2,442
86
3.5
1842 3,287
518
15.8
2,659
202
7.6
1843 3,060
274
9.0
2,739
164
6.0
1844 3,157
260
8.2
2,956
68
2.3
1845 3,492
241
6.9
3,241
66
2.0
1846 4,010
459
11.4
3,754
105
2.8
“cadaverous particles”
Institute of Chemistry of Ireland Annual Congress
Friday, 27th May 2011
Rev. No: C
Issue Date: 08/06/2010
Owner: B. Duffy
Hospital Superbugs
•75% of the total 8,000 cases of hospital acquired
infections (HAI) were due to the superbug MRSA
(Methicillin Resistant Staphylococcus Aureus) in
Ireland. Other more virulent strains such as KPC &
NDM-1
•Annual cleaning bills for Irish hospitals are €68 million
and the total economic burden of hospital acquired
infection is over €150 million every year.
•The proportion of MRSA observed in Ireland is one of
the highest in Europe
Institute of Chemistry of Ireland – Annual Congress
Friday, 27th May 2011
Rev. No: C
Issue Date: 08/06/2010
Owner: B. Duffy
A familiar photocatalyst product in the
market
Institute of Chemistry of Ireland Annual Congress
Friday, 27th May 2011
Rev. No: C
Issue Date: 08/06/2010
Owner: B. Duffy
How the titania coating in Pilkington glass
works as a superhydrophilic coating?
Oxygen
vacancies
Oxygen
vacancies
Oxygen
vacancies
O
Ti
Ti Ti
Ti
UV
UV
UV
Dark Dark
Dark
O O
O
Ti
Ti
H
O
O
H H
H
O
Ti
Ti Ti
Ti Ti
Ti
Ti
Hydrophobic
Hydrophobic
Hydrophobic
Ti
Ti
Ti
H
H
O O
O
Ti Ti
Ti Ti
Ti
Ti
Hydrophilic
Hydrophilic
Hydrophilic
Institute of Chemistry of Ireland Annual Congress
Friday, 27th May 2011
Rev. No: C
Issue Date: 08/06/2010
Owner: B. Duffy
O
O
Ti
Ti
Visible light active titania
Conventional TiO2 EBG= 3.2eV
Beforedoping
doping
Before
Visible light active TiO2 EBG < 3.2eV
After doping
After
doping
R. Asahi, T. Morikawa, T. Ohwaki, K. Aoki, Y. Taga, Science. 2001, 293, 269.
Institute of Chemistry of Ireland – Annual Congress
Friday, 27th May 2011
Rev. No: C
Issue Date: 08/06/2010
Owner: B. Duffy
First N-doped Titania (TiO2)
Asahi (2001)
• TiO2-xNx prepared by
sputtering with N2 and
annealing in N2
atmosphere at 550 oC
• Mixture of anatase and
rutile
• Yellow transparent films
Institute of Chemistry of Ireland Annual Congress
Friday, 27th May 2011
Rev. No: C
Issue Date: 08/06/2010
Owner: B. Duffy
Doping with non-metal ions
• Fluorine
(In collaboration with JM Kelly and I Gun’ko, TCD)
Chem. Mater., 19 (18), 2007, 4474-4481.
• Nitrogen
J. Phys. Chem. C, 111(4), 2007, 1605–1611.
• Sulphur
J. Phys. Chem. C, 112 (20), 2008, 44–7652.
• Nitrogen and Sulphur
J. Phys. Chem. C, 113,(8),2009, 3246-3253.
• Nitrogen doped heterojunctions
•
Chem. Mater., 22, 2010, 3843–3853
Institute of Chemistry of Ireland – Annual Congress
Friday, 27th May 2011
Rev. No: C
Issue Date: 08/06/2010
Owner: B. Duffy
Challenge: Anatase to Rutile Transformation
600 to 700 C in pure titania
600- 700 C
Ti
Ti
Ti
Ti
Ti
Ti
Anatase
(Edge shared)
Rutile
(Corner shared)
Photocatalytic Phase
Non-Photocatalytic Phase
Institute of Chemistry of Ireland – Annual Congress
Friday, 27th May 2011
Rev. No: C
Issue Date: 08/06/2010
Owner: B. Duffy
How a delayed phase transition happens
Institute of Chemistry of Ireland – Annual Congress
Friday, 27th May 2011
Rev. No: C
Issue Date: 08/06/2010
Owner: B. Duffy
Effect of S- doping
J. Phys. Chem. C, 112 (20), 2008, 44–7652.
Institute of Chemistry of Ireland – Annual Congress
Friday, 27th May 2011
Rev. No: C
Issue Date: 08/06/2010
Owner: B. Duffy
Sunlight Driven Photocatalysis- 850OC calcined samples
(a) Control sample
210 minutes
J. Phys. Chem. C, 112 (20), 2008, 44–7652.
(b) S-doped sample
35 minutes
Institute of Chemistry of Ireland – Annual Congress
Friday, 27th May 2011
Rev. No: C
Issue Date: 08/06/2010
Owner: B. Duffy
Mechanism of doping
Reduction:
Conduction Band
-
electron
Ti 3d
O2 + e- → O2-•
Super oxide
radical
hv > 390 nm
Band Gap (Eg)
hv < 390 nm
2.45 eV
N 2p
mid-gap
+
hole
O 2p
Oxidation:
H2O + h+ → OH•
Hydroxyl radical
Valence Band
Institute of Chemistry of Ireland – Annual Congress
Friday, 27th May 2011
Rev. No: C
Issue Date: 08/06/2010
Owner: B. Duffy
A Photocatalytic Tile?
• High temperature stable anatase phase (above 1000OC)
• Visible light activity by doping
•
A stable anatase phase up to the sintering temperature of the ceramic
substrates is most desirable for applications on anti-bacterial ceramic
materials (e.g. bathroom tile, sanitary ware etc.).
Institute of Chemistry of Ireland – Annual Congress
Friday, 27th May 2011
Rev. No: C
Issue Date: 08/06/2010
Owner: B. Duffy
Anti-bacterial Ceramic Tiles- Challenges
• High Sintering temperature
(above 1000OC).
• Photocatalytic phase anatase
change to rutile at 600O to 700OC
• High temperature stability and
visible light activity are requisite
Institute of Chemistry of Ireland – Annual Congress
Friday, 27th May 2011
Rev. No: C
Issue Date: 08/06/2010
Owner: B. Duffy
Examples of RADICAL’s anti-bacterials
Photocatalyst products
Institute of Chemistry of Ireland – Annual Congress
Friday, 27th May 2011
Rev. No: C
Issue Date: 08/06/2010
Owner: B. Duffy
Turkish Trials
Institute of Chemistry of Ireland – Annual Congress
Friday, 27th May 2011
Rev. No: C
Issue Date: 08/06/2010
Owner: B. Duffy
Anti-bacterial Tiles
Institute of Chemistry of Ireland – Annual Congress
Friday, 27th May 2011
Rev. No: C
Issue Date: 08/06/2010
Owner: B. Duffy
Anti-MRSA High Tc Tiles
a
b
Anti-MRSA test of titania samples (a) control (b) CREST TiO2
Institute of Chemistry of Ireland – Annual Congress
Friday, 27th May 2011
Rev. No: C
Issue Date: 08/06/2010
Owner: B. Duffy
External Antimicrobial Testing against E. coli;
Airmid healthgroup , using ISO 27447: 2009
VitrA photocatalytic wall
tiles
Conclusion
The presence of visible light killed all the E. coli on VitrA photoactive ceramic tile
(Sample A1)
Institute of Chemistry of Ireland – Annual Congress
Friday, 27th May
2011 (Too Numerous To Count, TNTC)
A normal tile showed no change in antibacterial
count
Rev. No: C
Issue Date: 08/06/2010
Owner: B. Duffy
Conclusions
•
•
•
•
A novel industrial viable technology has been developed to
prepare visible light active titania.
A high temperature stable photo-active titania has been
developed
Anti-MRSA ceramic tiles have been produced
Industrial pilot plant operation has been successfully
carried out.
Institute of Chemistry of Ireland – Annual Congress
Friday, 27th May 2011
Rev. No: C
Issue Date: 08/06/2010
Owner: B. Duffy
Enterprise Ireland ARE programme
Dr Suresh Pillai
Dr John Colreavy
Dr Hugh Hayden
Mr Darragh Ryan
Dr Pradeepan Periyat
Dr Michael Seery
4/13/2015
Institute of Chemistry of Ireland – Annual Congress
Friday, 27th May 2011
Rev. No: C
Issue Date: 08/06/2010
Owner: B. Duffy
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