Commercialisation of ChemistryVisible light semiconductor photocatalysts a novel hygiene solution Declan McCormack (DIT) and Robert Hickson (Vitra)

Institute of Chemistry of Ireland Annual CongressFriday, 27th May2011

Titania (TiO2)Precipitation of submicron high surface area seconducting titania as a support for metal oxide anodic catalysts, mainly for fuel cells.Nafion

Institute of Chemistry of Ireland Annual CongressFriday, 27th May2011

Ignatz Semmelweis (1818-1865)1847- Childbed (Puerperal) Fever in Vienna Hospital Obstetrical Cliniccadaverous particles

First clinic

Second clinic

Year

Births

Deaths

Rate (%)

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

Institute of Chemistry of Ireland Annual Congress Friday, 27th May2011

Hospital Superbugs75% 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 CongressFriday, 27th May2011

A familiar photocatalyst product in the market

Institute of Chemistry of Ireland Annual CongressFriday, 27th May2011

How the titania coating in Pilkington glass works as a superhydrophilic coating?

Institute of Chemistry of Ireland Annual Congress Friday, 27th May2011

Visible light active titaniaVisible light active TiO2 EBG < 3.2eVR. Asahi, T. Morikawa, T. Ohwaki, K. Aoki, Y. Taga, Science. 2001, 293, 269.Conventional TiO2 EBG= 3.2eV

Institute of Chemistry of Ireland Annual CongressFriday, 27th May2011

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 May2011

Doping with non-metal ionsFluorine (In collaboration with JM Kelly and I Gunko, TCD)Chem. Mater., 19 (18), 2007, 4474-4481. Nitrogen J. Phys. Chem. C, 111(4), 2007, 16051611.Sulphur J. Phys. Chem. C, 112 (20), 2008, 447652.Nitrogen and Sulphur J. Phys. Chem. C, 113,(8),2009, 3246-3253. Nitrogen doped heterojunctions Chem. Mater., 22, 2010, 38433853

Institute of Chemistry of Ireland Annual Congress Friday, 27th May2011

Challenge: Anatase to Rutile Transformation 600 to 700 C in pure titania

Photocatalytic PhaseRutile(Corner shared)600- 700 CAnatase(Edge shared)Non-Photocatalytic Phase

Institute of Chemistry of Ireland Annual Congress Friday, 27th May2011

How a delayed phase transition happens

Institute of Chemistry of Ireland Annual Congress Friday, 27th May2011

Effect of S- dopingJ. Phys. Chem. C, 112 (20), 2008, 447652.

Institute of Chemistry of Ireland Annual Congress Friday, 27th May2011

Sunlight Driven Photocatalysis- 850OC calcined samples(a) Control sample210 minutes(b) S-doped sample 35 minutesJ. Phys. Chem. C, 112 (20), 2008, 447652.

Institute of Chemistry of Ireland Annual Congress Friday, 27th May2011

Mechanism of doping

Institute of Chemistry of Ireland Annual Congress Friday, 27th May2011

A Photocatalytic Tile?High temperature stable anatase phase (above 1000OC)Visible light activity by dopingA 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 May2011

Anti-bacterial Ceramic Tiles- Challenges High Sintering temperature (above 1000OC).Photocatalytic phase anatase change to rutile at 600O to 700OCHigh temperature stability and visible light activity are requisite

Institute of Chemistry of Ireland Annual Congress Friday, 27th May2011

Examples of RADICALs anti-bacterials Photocatalyst products

Institute of Chemistry of Ireland Annual Congress Friday, 27th May2011

Turkish Trials

Institute of Chemistry of Ireland Annual Congress Friday, 27th May2011

Anti-bacterial Tiles

Institute of Chemistry of Ireland Annual Congress Friday, 27th May2011

Anti-MRSA High Tc Tiles Anti-MRSA test of titania samples (a) control (b) CREST TiO2

Institute of Chemistry of Ireland Annual Congress Friday, 27th May2011

External Antimicrobial Testing against E. coli; Airmid healthgroup , using ISO 27447: 2009

Institute of Chemistry of Ireland Annual Congress Friday, 27th May2011

ConclusionsA 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 May2011

Enterprise Ireland ARE programme

*Dr Suresh PillaiDr John ColreavyDr Hugh HaydenMr Darragh RyanDr Pradeepan PeriyatDr Michael Seery

The hydrophilic mechanism is believed to be as follows; electrons reduce the Ti (IV) cations to the Ti (III) state, and the holes oxidise the O2- anions. In the process, oxygen atoms are ejected and oxygen vacancies are created (figure 1.10). Water molecules can then occupy these oxygen vacancies, producing adsorbed OH groups, which tend to make the surface hydrophilic.

*The hydrophilic mechanism is believed to be as follows; electrons reduce the Ti (IV) cations to the Ti (III) state, and the holes oxidise the O2- anions. In the process, oxygen atoms are ejected and oxygen vacancies are created (figure 1.10). Water molecules can then occupy these oxygen vacancies, producing adsorbed OH groups, which tend to make the surface hydrophilic.

*Klebsiella pnuemoniaeBefore going into the technical details, I will give you an example of a familiar product, Pilkington activ self-cleaning glass. This is a normal glass which is hydrophobic, means water forms droplets. Pilkington uses titania coatings which makes it super hydrophilic so that water will form as a thin film and no droplets. *The hydrophilic mechanism is believed to be as follows; electrons reduce the Ti (IV) cations to the Ti (III) state, and the holes oxidise the O2- anions. In the process, oxygen atoms are ejected and oxygen vacancies are created (figure 1.10). Water molecules can then occupy these oxygen vacancies, producing adsorbed OH groups, which tend to make the surface hydrophilic.

*The hydrophilic mechanism is believed to be as follows; electrons reduce the Ti (IV) cations to the Ti (III) state, and the holes oxidise the O2- anions. In the process, oxygen atoms are ejected and oxygen vacancies are created (figure 1.10). Water molecules can then occupy these oxygen vacancies, producing adsorbed OH groups, which tend to make the surface hydrophilic.

**The formation of anatase is delayed due to the formation of SO4 tetrahedra and TiO6 octahedra and subsequently the rutile formation is delayed.** Steering CommitteePhotocatalyst does not only kill bacteria cells, but also decompose the cell itself. The titaniumdioxide photocatalyst has been found to be more effective than any other antibacterial agent,because the photocatalytic reaction works even when there are cells covering the surface andwhile the bacteria are actively propagating. The end toxin produced at the death of cell is alsoexpected to be decomposed by photocatalytic action. Titanium dioxide does not deteriorate and it shows a long-term anti-bacterial effect. Generally speaking, disinfections by titanium oxide isthree times stronger than chlorine, and 1.5 times stronger than ozone.Steering Committee*