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Running head: Artificial Photosynthesis
The Process of Artificial Photosynthesis
Corey Thrasher
Independent Study
Mrs. Graves
June 9th, 2015
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What I knew and What I wanted to know
In today’s world, there is a current and dangerous energy crisis. Gas prices at service stations are
rising as the abundance of oil decreases. Many alternative energy sources have been developed;
however, every alternative energy source comes with their own limitations and flaws. Solar energy can
only be produced during sunlight. Hydroelectric power can only be obtained at a dam or a flowing river.
Wind power can only be collected when there is strong enough winds to push the turbines. Also, each of
these alternative energy sources comes with a high initial cost that is difficult to pay. It takes many years
to turn a profit on systems such as these. I have always wondered if there was a better way to produce
energy since humanity obviously is in dire need of a large renewable energy source. Also, I have
developed an interest in the fields of chemistry and biology, so I wished to combine my passions into a
solution.
I didn’t know much about artificial photosynthesis besides what I knew about natural
photosynthesis. Basically, I understood that artificial photosynthesis is a process in which light is
absorbed to produce a product that contains high amounts of energy. I also knew that this system was
driven by a series of oxidation and reduction reactions; however, I had no idea how this was possible
without the use of biological agents which are utilized in natural photosynthesis. I’m a type of person
that likes to understand things on a level that allows me to truly comprehend a subject to the point
where it’s an extension of my own consciousness. I needed to know what I didn’t understand, so I could
know what to research.
I compared my knowledge of natural photosynthesis to artificial photosynthesis, so I knew
where the black spots were. First I needed to initiate some capacity building. How does artificial
photosynthesis work? What products can be produced by artificial photosynthesis? Can artificial
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photosynthesis be integrated into the global energy system? As I formulated my questions for capacity
building, I soon discovered that they all had an over-arching question. How can artificial photosynthesis
be used as an energy source?
The Story of My Search
As I might have expected, artificial photosynthesis is an extremely complicated region of
science, and today, the process is still not perfected to the point that it is ready for industrial or
commercial use. Before I realized I had an interest in artificial photosynthesis, I was enrolled in magnet
molecular biology as a requirement of the math and science academy. Little did I know that this class
would lead me to discover my passion within the field of chemistry. My magnet molecular biology
teacher Mrs. Jackson, having a true appreciation for the science behind her profession, took her time to
explain natural photosynthesis to our class. We spent two weeks to understand how the electrons
excited by photons moves along the reduction and oxidation cycle. Without the information that I
learned in magnet molecular biology, I wouldn’t have been able to research artificial photosynthesis and
be able to grasp it within the time period I was given in academic study.
Also, I took AP chemistry as an elective since I was so intrigued by this field of science when I
was required to take magnet chemistry in ninth grade. As I was learning the science behind natural
photosynthesis in magnet molecular biology, I was able to apply my knowledge from AP chemistry to
give me a valid and true understanding of the process both on the molecular level and the chemical
level. With this basic knowledge, I raced to the computer to begin my research. As most teenagers do
when they are required to research, I went to Wikipedia the free encyclopedia. Surprisingly, there were
in depth descriptions of the artificial photosynthesis process. I began to understand; however, I realized
that the information I was given was still too over my head for me to able to obtain an accurate
understanding of the process.
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Another potentially fantastic aspect of Wikipedia, which most teachers don’t respect, is that at
the bottom of the research article, there are many sources listed. These sources were used to compile
the massive amount of information that appeared on Wikipedia, so I began looking at each of the
supporting articles individually in order to better understand the subject. Many of the articles I
researched through this process were scientific journals. As you might imagine, scientific journals are
written for other scientists, so I still had a lack of understanding for the language of the discipline. There
was a brief period of time where I didn’t have an idea of how to be able to grasp the subject. I believed
that I had dived in to an intellectual pool that was much too out of my depth.
On the following class, I began my research. On this attempt, I simply went down the list of
websites that were loaded up when I typed artificial photosynthesis into the google search bar. Using
this method, I found many sites that split the process of artificial photosynthesis into its individual steps.
This greatly clarified the conundrum of artificial photosynthesis that still confuses many scientists to
date. After developing a basic view of artificial photosynthesis, I reread the scientific journals. With
clarity, I then began to understand the concept with some level of deeper understanding; however, I will
not lie. The information was still very confusing, and there is still much that I need to learn. I began my
notes section using the complex information of the scientific research articles. Then, I used my basic
understanding of the subject from other websites and natural photosynthesis to covert the complex
terminology into something that was easily understandable to me.
The next step in this research process was to attempt to contact a professional with knowledge
of the subject or a related field. As you might have guessed, the first person that came to mind was my
magnet microbiology teacher, Mrs. Jackson. I developed a professional academic resume to be sent to
Mrs. Jackson. Accompanying this letter, I delivered a letter of introduction which explained my
intentions with relation to my research on artificial photosynthesis. To my great disappointment, Mrs.
Jackson stated that I had learned well from her, and she could teach me no more than what she knew of
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natural photosynthesis within biological organisms. I had hoped that she would we able to clarify some
remaining holes in my understanding of the subject; however, she referred me to the Ocean Lakes
Biochemistry teacher. I was unable to set up a meeting with her in a timely manner that would have
influenced this I search paper, but she will be a boundless resource in the future. With the knowledge
that I learned, I hope to continue my research. This will hopefully transform into the ground work for
senior project, and I can definitively answer my original research questions.
The Search Results
Artificial Photosynthesis is a chemical process that replicates the natural process of
photosynthesis performed by plants and photo-bacteria. In both processes, carbon dioxide, water, and
sunlight are converted into carbohydrates and oxygen gas; however, the methodology used in artificial
photosynthesis is much more efficient than its natural counter-part. This is the reason that it is so
important. Artificial photosynthesis can be a viable alternative energy source to take the place of
harmful fossil fuels. Also, being that it uses solar energy to produce a variety of desired products, its
potential is somewhat limitless.
Artificial photosynthesis is accomplished either by a completely mechanical process or by a duel
process which involves the use of bacteria. As in natural photosynthesis, energy must be collected from
light. This is energy is absorbed in the form of photons. Select compounds and chemicals, such as
fluorine, pyrene, and byodipy, are used to capture the photons from different areas of the visible light
spectrum. In this fashion, the complete spectrum can be utilized in the process, increasing efficiency.
The light harvesting complex transfers the photons' energy to the reaction complex, which leads to an
electron being excited out of the complex. This electron is carried through the entire process in which it
creates a current. This current causes a series of reduction/ oxidation reactions. Usually, a
chromosphore is used as the reaction complex1.
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The energy from the electron transfer is converted to electrochemical energy (redox
equivalents). Then, a water oxidation complex uses this redox potential to catalyze conversion of water
to hydrogen ions or protons, electrons stored as reducing equivalents, and oxygen. A second catalytic
system uses the reducing equivalents to make fuels such as carbohydrates, lipids, or hydrogen gas. This
is the process where carbon dioxide is reduced to create the desired products. The oxidation/reduction
redox reactions are accompanied by catalysts that lower the activation energy so the reactions can
occur at reasonable and profitable rates. These catalysts can be either biological enzymes are simple
inorganic substances. Hydrogenase, a natural catalysts for the reduction of water to hydrogen fuel can
be a coupled process to the artificial photosynthesis process. Manganese, gold, and rubidium are typical
catalysts for the oxidation and reduction reactions2.
The electron eventually cycles back into the chromosphore to replace the electron lost, and the
process continues. A similar version of artificial photosynthesis uses a bioreactor. In this process,
tungsten and platinum nano-tubing captures photon energy, and transfers this energy to bacteria and
cyanobacteria. In one, a reduction process occurs, and in the other bacterium a oxidation reaction
occurs. The process is also cyclic. The difference using this process is that different products can be
made. Also, there are varying efficiencies. Since this process is designed to be more efficient, it can be
used as an alternative energy source. The energy produced by this process could be a viable way to
power our world as we attempt to cut our use of fossil fuels3.
Artificial Photosynthesis produces energy by absorbing photons that drive a series of redox
reactions resulting in a desired product, usually being hydrogen fuel. The energy stored within this fuel
can be released via burning and converting it to electricity. This electricity can then be added to the
electrical grid, adding to the available energy for human consumption2. This is important since humanity
is running out of viable resources for energy production, and artificial photosynthesis represents a
limitless source of power.
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To determine if artificial photosynthesis can be a viable option to implement into the global energy
system, we must first look at its possible products. Artificial Photosynthesis can produce a variety of
products: Hydrogen fuel, bio-degradable plastics, medicines, simple carbohydrates, and other chemicals
like acetate. However, not all of these products can be converted to electrical energy. Hydrogen fuel can
be ran through a combustion generator to produce electrical energy4.
The energy produced by an artificial photosynthesis process varies depending on the focal point of
light hitting the light harvesting points on the system. So, an artificial photosynthesis system can't be
connected directly into the global energy system because the electrical grid can only receive energy in
fixed quanta. An option to get around the quanta problem is to store the energy before implementing it
into the global energy system. To do this, the use of batteries would be required, and they would need
to be able to store considerable amounts of energy. Previously mentioned in one of my blog posts are
liquid fuel cells or "flow" batteries. These batteries can store large amounts of energy and implement it
out steadily over a set period of time3, 5.
Artificial photosynthesis can be used to create a great array of products. These products can be used
for energy consumption, fuel, and medicine among other things. This is incredibly important because
the Earth is running out of fossil fuels, and the percentage of carbon dioxide in the atmosphere is
reaching levels where an ice-age could emerge. This could be a renewable source of energy.
Recent discoveries in artificial photosynthesis have been achieved with the formulation of a network
that can absorb carbon dioxide (CO2) emissions before they are released into the atmosphere and then,
powered by solar energy, convert that CO2 into valuable chemical products, including biodegradable
plastics, pharmaceutical drugs and even liquid fuels. Scientists are also developing a so-called gaselectrolysis system^3. This consists of an electrolyte sandwiched between two thin porous electrodes
that mimics some of the processes occurring in leaves, but at a much larger scale. Close contact
between CO2 and water molecules occurs in the artificial system. When gold, a catalyst, is added to
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boost the process, the CO2 is transformed into carbon monoxide and the water into hydrogen. With
scaling-up of the system, this mixture of gases could be processed into various fuels, including hydrogen,
or useful organic materials such as alcohol^6.
Scientists with the U.S. Department of Energy’s Lawrence Berkeley National Laboratory and the
University of California Berkeley have created a hybrid system of semiconducting nanowires and
bacteria that mimics the natural photosynthetic process by which plants use the energy in sunlight to
synthesize carbohydrates from carbon dioxide and water. However, this new artificial photosynthetic
system synthesizes the combination of carbon dioxide and water into acetate, the most common
building block today for biosynthesis^4. While some research groups are particularly interested in using
the technology to mop up CO2 and so counter global warming, he says the potential benefits are much
broader than that. Outputs could include: proteins for feeding humans and livestock; sugars for direct
consumption; cellulose fibers for use as textiles; isoprene, rubbers and sealants; or sustainable fuels
including hydrogen (from water) and ethanol^1. Most of the Hydrogen based products can be used to
produce electricity at an industrial scale. In a sudo-mechanical-biological system, many carbohydrates
can be produced via the use of bacteria. This in turn can provide food, energy, and medicine^2.
Most of the bio-fuels produced can be decomposed to form natural gas or methane gas, the
main component of natural gas. This is a clean burning fuel. Interestingly, this process can produce biodegradable plastic which could eventually save the environment from the massive amount of littered
plastic produced by humanity^3. Until the efficiency of the system is increased, the products will not be
worth the initial cost. Since artificial systems consume carbon dioxide in the process of artificial
photosynthesis, they could be used to filter the excess CO2 out of the atmosphere^6.
After this research, I have learned a lot about artificial photosynthesis. This information will be
important in the future in relation to my academic research for my senior project. Artificial is a vast and
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complicated subject, but I have developed a desire to continue my compiling of knowledge within the
subject area of artificial photosynthesis.
MY GROWTH AS A RESEARCHER
During this tremendous experience, I have truly grown as a researcher. I have learned how to
start with very little experience on a complicated subject and establish an understanding. As a result of
this I search paper, I have learned how to use google scholar to research scientific journals. Also, I have
learned how to establish contact with a professional via a letter of introduction. Although I received a
no, I have learned how to acquire knowledge through the aid of a professional, so this will greatly
benefit my journey to being a professional in the scientific community.
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Cited References
1. Listorti, A. (2009, December 12). Solar to Fuel. Nature Materials. Retrieved May 29, 2015,
from http://www.nature.com/nmat/journal/v8/n12/full/nmat2578.html
2. Bockris, M. (1985, August 13). On the splitting of water. International Journal of Hydrogen
Energy. Retrieved May 29, 2015, from http://www.sciencedirect.com/science/article/pii/0360319
985900254
3. Hammarström, L. (2008, March 27). Coupled electron transfers in artificial photosynthesis.
Retrieved May 29, 2015, from http://techtv.mit.edu/videos/633-daniel-nocera-describes-newprocess-for-storing-solar-energy
4. Tard, C. (2005, February 10). Synthesis of the H-cluster framework of iron-only hydrogenase.
Retrieved May 29, 2015, from http://www.nytimes.com/2015/04/23/business/energyenvironment/liquid-batteries-for-solar-and-wind-power.html?ref=science&_r
5. Heyduk, A. (2001, August 31). Artificial Science. Retrieved May 29, 2015, from
http://www.ecosmagazine.com/?act=view_file&file_id=EC117p10.pdf
6. Yano, J. (2005, August 23). X-ray damage to the Mn4Ca complex in single crystals of
photosystem II. Retrieved May 29, 2015, from http://www.sciencedirect.com/science/articl
e/pii/S1369702108702505