EdUHK’s Professor Keith Ho: Novel Air Purifiers Using New LED Activated Graphitic Carbon Nitride Photocatalyst

Invented by Professor Ho Wing-kei at the Department of Science and Environmental Studies of The Education University of Hong Kong (EdUHK), 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.

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The Education University of Hong Kong

Nestled in a scenic mountain range, just one hour from Hong Kong’s business districts, The Education University of Hong Kong (EdUHK) offers tranquility and world-class scholarship in a vibrant, inclusive community. EdUHK is a publicly funded tertiary institution dedicated to the advancement of teaching and learning through diverse academic and research programmes on teacher education and complementary disciplines, including social sciences and humanities. The University places great emphasis on research capability with the aim of contributing to the advancement of knowledge, scholarship and innovation. EdUHK is committed to creating a sustainable impact on social progress and human betterment and defining the education landscape for not only Hong Kong, but also the Asia Pacific region. Ranked 3rd in Asia and 16th in the world in Education (QS World University Rankings by Subject 2021), EdUHK will continue to make an impact locally, regionally and internationally through high quality research and scholarship. Adopting an Education-plus approach, its primary mission is to lead educational innovation, and to promote and support the strategic development of teaching, teacher education and disciplines complementary to education by preparing outstanding and morally responsible educators and professionals while supporting their lifelong learning. To know more about EdUHK, please visit

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