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| Fig. 1: Shows the way photosynthesis, and therefore artificial photosynthesis works to create oxygen and energy. (Source: Wikimedia Commons) |
Artificial photosynthesis, much like natural photosynthesis, describes a process of energy transformation in which light energy is converted into chemical energy. Carbohydrates, such as sugars, and oxygen are synthesized from carbon dioxide, sunlight, and water (Fig. 1). Artificial photosynthesis is man's attempt to learn from and reap the benefits of its natural counterpart while achieving results by means of more efficient and controlled man-made systems. [1] Through artificial photosynthesis, it is possible to produce fuel within a consolidated network, bypassing transitional energy couriers. [1]
Water splitting, using artificial photosynthesis, makes possible the quasi-natural production of a "clean and storable fuel," without harmful byproducts such as greenhouse gases or air pollutants. [2] The chemical separation of liquid water yields hydrogen and oxygen in their gaseous forms. Hydrogen gas (H2) can either be used directly as a fuel or as a reactant to produce yet another fuel, one that more closely resembles the liquid fuel society uses today. [2] Most large-scale methods of splitting water incorporate photovoltaic-electrolysis, photochemical, and photoelectrochemical systems, however these systems are not efficient enough relative to today's technology to be economically viable. [3] Thus, although water splitting is a promising alternative to current means of generating energy, especially given water's affordability and accessibility, the cost of H2 production via artificial photosynthesis must be considerably reduced. However, auspicious success was made towards an economically viable system in February of this year when researchers at the Technion-Israel Institute of Technology used nanoparticle-based photocatalysts to achieve "100% photon-to-hydrogen production efficiency." [4]
Scientists have created an artificial leaf that accomplishes the same photosynthetic processes as its natural counterpart. It it capable of using water, sunlight, and carbon to produce a fuel for human use. Although it is not yet entirely cost efficient, scientists have been successful in creating an artificial leaf that is 10 times more effective than a natural leaf, retaining 10% of solar energy it is exposed to as opposed to the natural leaf's 1% retention rate. [5] With society's enormous push to halt its reliance on fossil fuels, artificial leaves serve as a plausible alternative to ubiquitous nonrenewable fuels. This is especially true considering the large amounts of federal funds being directed towards research and development of green technology and solar panels. Eventually, the artificial leaf could become a household item for people trying to "go green" while also attempting to subsidize their electricity costs.
© Cory Baird. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
[1] L. Hammarström, "Artificial Photosynthesis and Solar Fuels." Acc. Chem. Res. 42, 1859 (2009).
[2] A. J. Bard and M. A. Fox, "Artificial Photosynthesis: Solar Splitting of Water to Hydrogen and Oxygen," Acc. Chem. Res. 28, 141 (1995).
[3] J. Jia et al., "Solar Water Splitting by Photovoltaic-Electrolysis With a Solar-to-Hydrogen Efficiency Over 30%," Nat. Commun. 7, 13237 (2016).
[4] P. Kalisman, Y. Nakibli, and L. Amirav. "Perfect Photon-to-Hydrogen Conversion Efficiency," Nano Lett. 16, 1776 (2016).
[5] R. Martin, "A Big Leap for an Artificial Leaf," Technology Review, 7 Jun 16.
