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Commercialisation of Chemistry Visible light semiconductor photocatalysts – a novel hygiene solution. Declan McCormack (DIT) and Robert Hickson (Vitra). Titania (TiO 2 ). Nafion.
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Commercialisation of ChemistryVisible light semiconductor photocatalysts – a novel hygiene solution Declan McCormack (DIT) and Robert Hickson (Vitra)
Titania (TiO2) Nafion Precipitation of submicron high surface area seconducting titania as a support for metal oxide anodic catalysts, mainly for fuel cells.
Ignatz Semmelweis (1818-1865) 1847- Childbed (Puerperal) Fever in Vienna Hospital Obstetrical Clinic “cadaverous particles”
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
How the titania coating in Pilkington glass works as a superhydrophilic coating?
Visible light active titania Conventional TiO2 EBG= 3.2eV Visible light active TiO2EBG < 3.2eV R. Asahi, T. Morikawa, T. Ohwaki, K. Aoki, Y. Taga, Science. 2001, 293, 269.
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
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
Challenge: Anatase to RutileTransformation 600 to 700 C in pure titania 600- 700 C Anatase (Edge shared) Rutile (Corner shared) Photocatalytic Phase Non-Photocatalytic Phase
Effect of S- doping J. Phys. Chem. C, 112 (20), 2008, 44–7652.
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
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.).
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
Examples of RADICAL’s anti-bacterials Photocatalyst products
Anti-MRSA High Tc Tiles a b Anti-MRSA test of titania samples (a) control (b) CREST TiO2
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) A normal tile showed no change in antibacterial count (Too Numerous To Count, TNTC)
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.
Enterprise Ireland ARE programme Dr Suresh Pillai Dr John Colreavy Dr Hugh Hayden Mr Darragh Ryan Dr Pradeepan Periyat Dr Michael Seery 11/14/2014