The solar-driven photocatalytic splitting of water into hydrogen and oxygen is a potential source of clean and renewable fuels. Solar-to-fuel energy conversion alleviates the energy storage problem, since fuel (chemical energy) can be stored more easily than either electricity or heat. However, four decades of global research have proven this multi-step reaction to be highly challenging. Systems that are sufficiently stable and efficient for practical use have not yet been realized. Our group is particularly interested in photocatalysis on the nano scale and related photophysical and photochemical phenomena.
Photochemical Oxidation on Nanorod Photocatalysts
The combination of photochemical oxidation with colloidal synthesis enables us to re-think the design of photocatalysts with an eye towards overall water splitting. Here, IrO2 nanoparticle oxidative catalysts that were photodeposited on colloidal CdSe@CdS nanorod photocatalysts revealed a mediated oxidative pathway, and afforded the rods remarkable photochemical stability under prolonged illumination in pure water.
Morphological Effects on Photocatalytic Activity
Simple geometrical modifications of the photocatalyst enable manipulation of the photoinduced charge carriers and can significantly improve the catalytic efficiency. Our labs’ precise control over morphology facilitates innovative design, and construction of sophisticated nanoheterostructures, that will implement this finding. We have a few projects correlating structure, composition and morphology with photocatalytic activity towards H2 production. The information obtained will help us devise an efficient photocatalyst for widespread use.
Bi-Metallic Co-catalysts for Efficient Photocatalytic H2 Production
The research is concerned with the effect of a bi-metallic co-catalyst in a semiconductor–metal nanocomposite on interfacial charge-transfer processes and efficiency for photocatalytic hydrogen production. Semiconductor photocatalysts are often loaded with metallic co-catalyst, which presumably promotes charge separation of photogenerated electrons and holes and also acts as the site for the reduction reaction. These cocatalysts play an essential role in reactions such as water splitting, as they offer lower activation potentials for hydrogen evolution, and greatly enhance the photocatalytic activity. Utilization of a bi-metallic catalyst might enable separate optimization of the different interfaces that exist in such a heterostructure photocatalyst system.
Photocatalysis on the Nano Scale