Inspired by photosynthesis, the goal of artificial photosynthesis is to design a photocatalytic system that can produce fuels directly from water and carbon dioxide as well as degrade air pollutants for environmental remediation using renewable solar energy. Traditional photocatalysts such as titanium dioxide can only be activated by ultraviolet irradiation, which is only 3-5% of the solar spectrum. Therefore, it is necessary to develop a photocatalyst that is sensitive for visible-light activity. Organic polymeric catalyst, carbon nitride is a fascinating choice. The graphitic carbon nitride (g-C3N4) is the most stable allotrope of carbon nitride and has attracted much attention in recent years. Its appealing electronic structure, being a medium-band gap, indirect semiconductor can be activated by visible light. This allows its direct use in sustainable chemistry as a multifunctional heterogeneous metal-free catalyst, e.g. in degradation of environmental pollutants. Although significant efforts have been devoted to develop stable and efficient g-C3N4, their efficiencies are not high enough for practical applications. The low efficiencies may be attributed to their low surface areas or poor crystallinity. The catalytic, electronic and optical properties of the g-C3N4 are by principle adjustable, using the rich chemistry of carbon and nitrogen. Different studies have been conducted to bind or intercalate different compounds, metals or non-metals into the matrix, which provides a convenient means of fine-tuning the structure and reactivity of g-C3N4. As a proof-of-concept, the deign highly efficient g-C3N4 photocatalyst will offer new inroads into exploration and utilization of solar/visible-light-driven photocatalst for air purification.

 

Dr. Keith Ho is the Associate Professor of the Department of Science and Environmental Studies at EDUHK. Dr. Ho received his BSc and PhD in CUHK, and was then awarded the post-doctoral fellowships in Hong Kong and Canada. Dr. Ho’s current research mainly focuses air pollution control, environmental technology and nanotechnology.