solar energy conversion is one of the most important and highly demanded
technologies for the 21st century. Large quantities production of solar fuels
requires the acquirement of solar light from a large area. A photocatalytic
overall water splitting system consists of a photocatalyst, water and solar
light, producing a very simple system that leads to high scalability.
Development of visible-light-responsive photocatalysts is desired to achieve a
low-cost, scalable energy conversion industry. The complexity of the reaction
requires accumulated knowledge of solid state physics, electrochemistry,
materials science and chemical engineering. KCC has been organizing a team that
includes internationally renowned collaborators to achieve this complex reaction
scheme to develop a highly efficient water splitting device.
Recombination of photo-generated electrons and holes reduces the overall efficiency of photocatalytic processes. By understanding the general scheme, including photo physical and electrocatalytic processes, the requirements for an efficient catalyst can be summarized as follows:
Suitable band positions (visible light responses) with a defect-free crystal structure (photocatalyst)
Enhanced charge separation of excited electrons and holes (interface and modified electronic structure);
Effective modifiers to accelerate surface reduction and oxidation reactions (cocatalyst);
Stability in water under irradiation (tolerance to photo-corrosion).