Yun Hau’s research is focused on the development of novel photoactive semiconductors (particles and thin film) for photocatalytic and photoelectrochemical processes. Photocatalysis is a solar energy conversion process, extensively investigated for both environmental remediation (e.g. airborne and water treatment) and energy application (e.g. hydrogen generation). His team is dedicated to explore the fundamental understanding in these excited charge-induced reactions: water splitting, hydrogen generation, CO2 reduction and charge storage (solar battery). Various strategies from materials nanostructuring to system engineering are adopted to investigate the scientific phenomena and boost the light energy conversion and utilization. Specific topics of interest include the suspension-type nanoparticulate photocatalytic and photoelectrochemical water splitting, electrochemical carbon dioxide reduction or conversion assisted with light, and other photocatalytic reactions for energy and environmental applications (e.g. ammonia generation from nitrate-containing waste stream). Integrated larger-than-laboratory scale system is investigated and built for potential real-life applications.