Researchers at The Chinese University of Hong Kong are further refining a sol-gel derived nanosized coating solution which can keep buildings clean and prevent seafood gourmets from contracting diseases like cholera.
The basis of their revolutionary NanoPCO™ cleaning technology is a photocatalytic layer of nano-particles which can be applied to buildings, or the filtration elements of water and air purifiers. Under ultraviolet light, the layers induce photocatalytic activity which can oxidise most known pollutants, and kill harmful bacteria in water and air.

Water disinfecting systems based on the technology are already in use in Hong Kong. Principal Investigator Prof Jimmy Yu and his team are now working on making the process more efficient by altering the sol-gel formula so that it reacts in an expanded portion of the useable solar spectrum.
Instead of the present effective range of shorter than 385 nanometres, or 3 to 5 per cent of sunlight’s spectrum, research is concentrated on a range of longer than 400 nanometres. A number of methods have been developed for visible light activation.
The latest discovery is that, by coupling titanium dioxide with a narrow band gap semiconductor, the photocatalytic response range can be shifted to between 400 and 600 nanometres.

Principal Investigator
Prof Jimmy C M Yu : jimyu@cuhk.edu.hk