Photocatalysis

The Sun is an (almost) infinite and costless source of energy that provides us with an amount of energy far exceeding our needs. Plants and some organisms have learned to exploit this unique privilege to live on our planet during millennia of evolution. The use of this clean and sustainable energy source would allow us to solve the problems connected to the utilization of fossil fuels.

There are however issues associated with solar energy, mainly related to the fact that it is a diffuse and intermittent source of energy. Harvesting and storing solar energy are therefore some of the key problems to overcome to achieve a truly sustainable energy scenario. Nanostructures are natural candidates for this role, because of their high surface-to-volume ratio that increases their capability to harvest solar radiation and because of their tunable properties that allow manipulation of their energy levels.

In analogy to how carotenes and chlorophylls harvest and transfer solar energy in plants, arrays of nanostructures can play this role and funnel energy to reactive centers for the transformation of solar into chemical energy in the form of chemical bonds. To this end, the production of liquid compounds where the energy is stored is one of the most attractive solutions.

Studying photocatalytic processes that turn solar energy into chemical energy is an important objective in the Cargnello group. Fundamentals of photocatalytic processes are studied by using uniform and tailored nanostructures based on abundant semiconductors.

The controlled positioning of building blocks is key to collect and transfer energy to reactive centers that are then capable of transforming abundant molecules into liquid fuels. To this scope, important compounds such as hydrogen (as a precursor for methanol) and methanol are the most interesting targets.