Invented by Professor Ho Wing-kei at the Department of Science and Environmental Studies of The Education University of Hong Kong, the novel graphitic carbon nitride photocatalyst provides an innovative way for environmental purification. Compared to the traditional photocatalyst such as titanium dioxide, which can only be activated by UV light, and has a relatively low effectiveness in air pollutant degradation, the newly developed photocatalyst can utilise visible light (daylight or indoor light) as the light source for photocatalytic reactions. 

Instead of using the conventional UV light tubes in photocatalytic environmental purification technology, this breakthrough makes applying visible light LED lighting, which is more energy-saving and environmentally friendly to photocatalysis become possible. The new technology can greatly enhance the efficiency in air pollutants degradation and disinfection. It also provides a promising approach in the development of portable air purifiers and construction materials with air cleaning function (such as flooring, ceilings and interior wall, etc). This, in turn, opens up a wide range of daily life applications using the related technology.

This new photocatalytic material consists of only carbon and nitrogen, which is metal-free and non-hazard. It is indoor/visible-light-driven and consuming no energy in air purification and disinfection. In addition, the new LED activated graphitic carbon nitride photocatalyst demonstrates prolong high efficiency (90% removal, last for one year) in the degradation of air pollutants such as nitrogen oxides and inactivation of bacteria. The new material’s synthesis and fabrication technology solution is developed which is ready-to-use in surface coating fabrication. It is applicable in producing construction materials, household ware and hospital facilities with air purification feature.

The innovation won the Gold Medal in the International Invention Innovation Competition in Canada in 2018. In the future, the team would study the performance of the photocatalytic material on various surfaces and in different forms to develop a board variety of air-purifier, such as a portable version.