Artificial Photosynthesis - Advantages, Disadvantages, and Efficiency

Advantages, Disadvantages, and Efficiency

Advantages of solar fuel production through artificial photosynthesis include:

• The solar energy can be immediately converted and stored. In photovoltaic cells, sunlight is converted into electricity and then converted again into chemical energy for storage, with some necessary loss of energy associated with the second conversion.
• The byproducts of these reactions are environmentally friendly. Artificially photosynthesized fuel would be a carbon-neutral source of energy, which could be used for transportation or homes.

Disadvantages include:

• Materials used for artificial photosynthesis often corrode in water, so they may be less stable than photovoltaics over long periods of time. Most hydrogen catalysts are very sensitive to oxygen, being inactivated or degraded in its presence; also, photodamage may occur over time.
• The overall cost is not yet advantageous enough to compete with fossil fuels as a commercially viable source of energy.

A concern usually addressed in catalyst design is efficiency, in particular how much of the incident light can be used in a system in practice. This is comparable with photosynthetic efficiency, where light-to-chemical-energy conversion is measured. Photosynthetic organisms are able to collect about 50% of incident solar radiation, but photochemical cells could use materials absorbing a wider range of solar radiation. It is however not straightforward to compare overall fuel production between natural and artificial systems: for example, plants have a theoretical threshold of 12% efficiency of glucose formation from photosynthesis, while a carbon reducing catalyst may go beyond this value. However, plants are efficient in using CO₂ at atmospheric concentrations, something that artificial catalysts still cannot perform.