Positive Impact

Running head: CARBON FIXATION FOR OXYGEN PRODUCTION
Producing Oxygen and Methane Through Artificial Photosynthesis Using Various
Sulfur-Based Catalysts
Catherine Heyboer
Oak Park and River Forest High School
Oak Park, IL
Positive Impact
February 19, 2016

CARBON FIXATION FOR ARTIFICIAL PHOTOSYNTHESIS
ABSTRACT
Fixation of Carbon Dioxide Into Oxygen and Methane Using Various Catalysts for
Artificial Photosynthesis
Catherine Heyboer
Oak Park and River Forest High School, Oak Park, IL
Supervisor: Mrs. Allison Hennings R.N., B.S.N., M.A.T.
Mentors: Prof. Dick Co Ph.D., Prof. Parisa A. Ariya, Ph.D., Prof. Bruce Arndtsen, Ph.D.
Global Warming is dangerously affecting the earth; and, therefore, various methods, such
as green fuels and biodegradable plastics, have been employed to alleviate the issue.
However, these methods can both be expensive and inefficient in short time periods. The
elimination of carbon dioxide (CO2) using water (H2O) and various catalysts in a carbon
fixation reaction based off of the reverse combustion of methane (CH4) was designed. A
solar-powered apparatus held the reaction (CO2 + X + H2O  O2 + CH4), where X was a
catalyst (CdS, ZnS, CuS). Both gases were let loose into the atmosphere after detecting
the presence of methane. Stoichiometry was then used to calculate the amount of
produced oxygen. The amount of methane was statistically significant for >80 ppm
(ANOVA p=0.000367), thus the null hypothesis is rejected. Therefore it can be
concluded that carbon fixation, producing both breathable air and a renewable fuel source
is a solution to the problem. Further research is needed in the area of harnessing produced
oxygen for industrial purposes.
Keywords: carbon fixation, artificial photosynthesis, catalytic reactions, global
warming, methane

CARBON FIXATION FOR ARTIFICIAL PHOTOSYNTHESIS
ACKNOWLEDGMENTS
The researcher would like to express deep gratitude to Professor Dick Co, Ph.D.,
research assistant professor of chemistry at Northwestern University, for providing
guidance and knowledge of solar energy and renewable resource. The researcher would
like to express deep gratification to Professor Parisa A. Ariya, Ph.D., professor of
chemistry and atmospheric and oceanic sciences at McGill University, for providing
immense knowledge of gases and the true relevance and impact of renewable resources.
The researcher would like to express deep gratitude to Professor Bruce Arndtsen, Ph.D.,
professor of chemistry at McGill University, for knowledge of metal catalysts. Mr. David
Bernthal, M.S, is appreciated for providing materials and insight for the procedure. Mr.
William Grosser, M.S., is thanked for providing overall insight and background
information about this research as well as materials and ideas. Oak Park and River Forest
Staff -- Dr. Ann Carlson, Ph.D., assisted in the research process by providing suggestions
and sources to obtain information; Mr. Matt Kirkpatrick (Science Division Head), Mr.
William Grosser (Chemistry), Mr. Kevin McKitrick (Physics), and Mr. John Costopolous
(Environmental Science), provided overall project guidance and IRDI approval; Mrs.
Allison Hennings, R.N., B.S.N., M.A.T., I.R.D.I. teacher, provided assistance,
unwavering support, and helpful, relevant ideas and solutions throughout the research
process, and experimentation. Mr. George M. Roman, B.S. Loyola University, B.MS,
student at Dominican University, provided additional resources in obtaining literature,
offered support, advice, skill, and his time in the classroom. Only with the aid of those
recognized was the researcher able to devise and execute this experiment and develop
this novel new method for artificial photosynthesis.

CARBON DIOXIDE FIXATION FOR ARTIFICIAL PHOTOSYNTHEIS
TABLE OF CONTENTS
List of Tables and Figures…………………………………….…………………………..1
Introduction………………………………………………………………………………..2
Methods of Procedure…………………………………………………………………….10
Results…………………………………………………………………………………….17
Discussion and Conclusions………………………………………………………………22
Positive Impact….………………………………………………………………………...26
References………………………………………………………………………………...29

1
LIST OF TABLES AND FIGURES
Figure 1 Light and Dark Reactions of Biological Photosynthesis .............................................3
Figure 2 Ring Structure of benzene............................................................................................4
Figure 3 Thymidine Kinase Enzyme..........................................................................................5
Figure 4 Procedure Flow Chart ................................................................................................11
Figure 5 Final Apparatus Set-Up..............................................................................................13
Figure 6 Produced Carbon Dioxide Captured and Measured...................................................14
Figure 7 Cadmium Sulfide Poured Into Reaction ....................................................................15
TABLE 1 Carbon Dioxide Production Pre-procedure................................................................17
TABLE 2 Summary of Ten Trials of Control Group .................................................................17
Figure 8 Seconds of >40 ppm of Methane Produced ...............................................................18
Figure 9 Seconds of >80 ppm of Methane Produced ...............................................................18
TABLE 3 Various t-tests Comparing the Catalyst and Control .................................................19
TABLE 4 Various ANOVA Tests Comparing the Catalysts and Control.................................22

2
INTRODUCTION
With the ozone tragically imbalanced, the earth is undergoing a drastic climate change. A
saturation of greenhouse gases, such as carbon dioxide, is causing this global warming, resetting
the ratio percentage of atmospheric gases (Vaidya, Kondura, Vaidyanathan, & Kenig, 2008). An
increase of greenhouse gases leads to an imbalance and need for oxygen. As a solution, scientists
have discovered various ways to combat the environmental crisis: carbon capture, biomass fuels,
water splitting, and optical fabrication (Noble, Walczak, & Dornfield, 2014). No current method
is efficient, cost effective, and applicable to societal needs and lifestyles. Artificial
photosynthesis therefore has interested many scientists as a method to increase oxygen content in
the atmosphere while simultaneously decreasing the carbon dioxide levels.
Carbon dioxide is a naturally occurring gas vital to life on earth, and it is the product of
all aerobic respiration. Too much carbon dioxide produced overheats the earth’s surface and
increases the acidity in bodies of water. Carbonic acid, though a weak acid, is formed when
carbon dioxide mixes with water (CO2 + H2O  H2CO3) (Jung, Reichstein, Margolis, Cescatti,
Richardson et al., 2012; Solomon, Plattner, Knutti, & Friedlingstein, 2009). The lack of dipole
moment in the linear structure of carbon dioxide, along with the double bond between the carbon
atom and each oxygen atom, renders carbon dioxide a fairly strong molecule. Bond length has a
direct relationship with bond strength; the shorter the length, the stronger the bond. Molecules
can have a single, double, or triple bond with a triple bond being the strongest. As a molecule,
carbon dioxide is strong due to the fact that it is made up of charged ions held close together in a
double bond. The lack of dipole moment caused by this double bond prevents a distortion of the
molecule (McNeill, Grannas, Abbatt, Ammann, & Ariya, 2012). A distortion allows for another
molecule or atom to bond, but, without one, carbon dioxide will rarely change its composition,

3
Figure 1. Biological photosynthesis includes catalysts,
intermediates, and products in both light and dark
reactions. Oxygen is produced in the light reaction,
whereas sugars are formed in the dark reaction.
(http://ww.uic.edu/classes/bios/bios100/lecturesf04am/lect
10.html). This study focused on the light reaction.
adding to its strength. In comparison, oxygen is a diatomic molecule with double polar covalent
bonds. Being that oxygen is the second most electronegative element, meaning it has a high
tendency to pull electrons towards itself, it can bond with other elements and produce molecules
such as carbon dioxide (Booth,
Anderson, Swannick, Wade, Kite et al.,
2004). Oxygen is a product of
photosynthesis that is made through four
steps: light harvesting, change separation,
water splitting, and fuel production as
demonstrated in Figure 1. In biological
photosynthesis, chlorophyll, the pigment
molecule, harvests energy, and water is
oxidized. Most photosynthetic autotrophs are less than ten percent efficient in converting solar
energy into carbohydrates and oxygen (Askari, 2013). Biological photosynthesis carried out by
plants and photosynthetic bacteria converts sunlight and other raw materials (water, carbon
dioxide) to create oxygen and organic fuels (Bard & Fox, 1995). The goal of artificial
photosynthesis is to mimic biological photosynthesis, using the sun to create a renewable fuel
source. Carbon fixation is the foundation of biological photosynthesis that converts inorganic
carbon into organic carbon. Artificial photosynthesis remains a complex and obscure technique.
Research has documented the use of biological photosynthesis as a blueprint for artificial
photosynthesis (Boucher, Friedlingstein, Collins, & Shine, 2009). There is not any documented
research in the literature that has successfully fixed carbon dioxide to produce oxygen and

4
methane. Therefore, no experiment has created a method in which breathable oxygen and
reusable methane that can be produced in an eco-friendly fashion. The present research
purposefully tackled this gap in order to develop a method that would simultaneously decrease
the carbon dioxide content in the atmosphere and increase the oxygen content.
Previous research conducted carbon dioxide-reducing experiments in two different ways:
coupling, cycloaddition. Carbon dioxide coupling is used in the pharmaceutical industry and in
conjugated organic compounds. Coupling is a process in which two
hydrocarbon fragments are coupled with the aid of a metal catalyst.
In doing so, various compounds and molecules can be built; these
molecules in turn are used commonly in manufacturing industries.
Specifically, ethylene oxide is an epoxide formed from coupling
that is used to make antifreeze (Cody, Boctor, Brandes,
Filley, Hazen, & Yoder, 2004). In one experiment,
Chiral (salen) Cobalt III was tested as a catalyst to aid
the ring openings of epoxides and yielded good results. Without epoxide rings opening, cyclic
carbonates cannot be produced; using a metal-based catalyst, such as Chiral (salen) Cobalt III
helps produce the cyclic carbonates in high yields (Miao, Wang, & He, 2008). Calcium
carbonate, produced this way, is used as a dietary supplement. Coupling can therefore reuse
carbon dioxide and create manufactured goods without producing pollutants.
In addition to coupling, cycloaddition is a method in which organic chemists can build
carbocyclic and heterocyclic structures. A carbocyclic structure is an organic compound whose
ring is made of only carbon atoms (see Figure 2). Heterocyclic structures are also organic
compounds, but the ring is formed from both carbon and non-carbon atoms. Nucleic acids,
Figure 2. Benzene has a ring structure
built of only carbon
(http://www.publicintegrity.org/2014/12/0
4/16320/benzene-and-worker-cancers-
american-tragedy).

5
biopolymers that carry genetic information essential to life, have long strands of heterocyclic
structures (see Figure 3.). These structures can then be used to develop a broad range of
functional materials including pharmaceuticals, agrochemicals, dyes, and optics (Miao, Wang, &
He, 2008; Armstrong, He, & Liu, 2009). Cycloaddition allows for
a quick, dual way to utilize carbon dioxide without creating by-
products or pollutants, similar to coupling. Beber, Caleiro, Rossi
de Aguiar, Joswig, Filho et al. (2015) attempted to fix carbon
dioxide through a synthesis process with epoxides to form cyclic
carbonate for eco-friendly plastics. It was determined
that when using 1,2-Epoxybutane (EB), a linear
molecule, plastics were able to be fabricated safely
without previously used toxic materials. Another study in 2005 tested the possibility of fixating
carbon dioxide using supercritical carbon dioxide to create cyclic carbonates simply and
efficiently. Using alkyl chains in an ionic liquid phase with a catalyst was found to yield almost
one hundred percent carbonate in a short time (Kawanami, Sasaki, & Ikushima, 2005). Changing
gaseous carbon dioxide into supercritical carbon dioxide is not easily done, but the ability to use
carbon dioxide to produce safe materials faster and more efficiently renders more carbon dioxide
to be recycled than the previous method demonstrated by Beber et al. This advancement in
research led to further development in biofuel research, specifically in gasification processes.
Gasification is a process that converts solid biofuel, such as hazelnut shells, into gaseous
fuel. To accomplish this conversion, the biofuel is mixed with another gas, commonly methane, a
naturally occurring, abundant gas (Panwar, Tyagi, & Kothari, 2012; Kang, Seo, Jang, & Seo,
2009). Combining methane with a biofuel results in a syngas, otherwise known as a producer
Figure 3. Thymidine kinase is an enzyme
that aids in DNA synthesis.It has a ring
structure composed of carbon and non-
carbon atoms
(http://pfam.xfam.org/family/PF00265).

6
gas, that can then be used as a fuel source. Though gasification does produce carbon by-products,
it altogether decreases the quantity of burned carbon by the ton in comparison to burning fossil
fuels as an energy resource (Panwar, Tyagi, & Kothari, 2012; Howarth, Santoro, & Ingraffea,
2011). The current research was developed to produce methane due to its application in biofuel
gasification.
Hydrogen production has become a new wave of green energy. In addition to
gasification, methane is used as a direct and indirect source of hydrogen (Arakawa, Dixon,
Fujita, Nicholas, & Sen, 2001). Steam methane reforming (SMR: CH4 + CO2  2CO + 2H2).
When hydrogen is produced using fossil fuels, carbon dioxide is a by-product, but if methane is
used, carbon dioxide is a reactant. In this indirect process, both methane and carbon dioxide are
consumed to produce a green energy fuel source thereby decreasing the greenhouse gas content
in the atmosphere and creating green energy (Lee, Kim, Lee, Lee, & Seo, 2015). Directly,
methane is able to decompose into hydrogen and carbon, which can then be converted into
various carbon-based molecules (4CH4  5H2 + C2H4 +C2H2). Methane thus produces a greater
quantity of hydrogen as well as carbon structures.
Solar panels convert the energy of photovoltaic systems, having many applications such
as aerospace industries, electric vehicles, and communication equipment. They absorb photons
and increase the energy levels of electrons, freeing them from the atom or molecule they were
previously attached to. The freeing of electrons creates a flow of electricity that the solar panel
can use. A solar panel’s energy output level is dependent on extrinsic variables, including
radiation levels and temperature (Chung, Tse, Hui, Mok, & Ho, 2013). To combat this issue,
maximizing the electrical output of solar panels can be done through sun tracking, maximum
power point tracking, or both. Sun tracking is a technique that allows for the panels to face the

7
sun throughout the day, turning to accommodate the changing position of the sun. Maximum
power point tracking, however, is most economical and provides the most power by applying the
correct resistance value despite temperature variations, a common mechanical problem with most
panels. Generally, the electrical power output tends to increase linearly with solar irradiance, the
power of electromagnetic radiation from the sun, and decreases directly with temperature
(Blankenship, Tiede, Barber, Brudvig, & Fleming et al., 2011).
Research conducted by Xia, Ng, An, Li, Li et al. (2013) discussed the activity of
cadmium sulfide and concluded that it was a notable catalyst. It is economically favorable, and
its properties as a transition metal are ideal. Because it is a transition metal, it transfers electrons
easily from the reactants to the products in a chemical reaction, oxidizing or reducing as
necessary. This flexibility allows for the reaction to proceed. In addition, it was found to be
magnetically separable, allowing for reuse, even after many uses. Recycling cadmium sulfide
only takes two steps: separation, and washing with deionized water and ethanol. This
recyclability is cost effective, environmentally favorable, and adds simplicity to the experiment
(Marafi & Stanislaus, 2008; Rodriguez & Hrbek, 1999). It was discovered that transition metals
such as cadmium were high yielding catalysts that increased the electron donor states, thereby
increasing the adsorption rate (Davies & Manning, 2008). Recent studies have shown that other
transition metals, such as zinc, were efficient catalysts for carbon coupling, cycloaddition, and
synthesis when bonded with another substance. The catalytic system, when using a zinc-based
catalyst, was seen to be highly selective in a heterogeneous mixture, rendering zinc an efficient
and easily reusable catalyst (Miao, Wang, & He, 2008). Working well with various carbon
reactions, it is not implausible to test zinc sulfide as a catalyst for carbon fixation. Its properties
as a transition metal are similar to those tested by Xia, Ng, An, Li, Li et al. (2013) on cadmium

8
sulfide. In comparison to alkali and alkali earth metals, transition metals have a low reactivity,
which was an advantage when testing cadmium sulfide, zinc sulfide, and copper (II) sulfide.
Copper (II) sulfide is low in toxicity and is found in children’s toy lab sets (Bagherzadeh, &
Mankad, 2015). This safety precaution was ideal for a shared laboratory environment. Because
copper (II) sulfide is soluble in water, no real environmental danger arises from working with
this chemical. It can be distributed in water or soil and tends to bind organic matter without
disrupting the existing acidity.
In nature, oxygen is produced through photosynthesis: plants and algae have evolved to
separate water into oxygen using electron transfer combined with oxidation and reduction
reactions (Babcock, 1998). Chlorophyll is very efficient in absorbing light and allows for the
conversion of excitation energy into an electrochemical potential via charge separation. This
reaction occurs when photons are absorbed and an electron is excited to a higher state, then
leaving the atom or molecule, and eventually producing oxygen through water oxidation.
Oxygen can also be formed with charged recombination, though this is a slower reaction
(Krieger-Liszkay, Fufezan, & Trebst, 2004). Scientists can produce oxygen through water
splitting techniques in the laboratory with photocatalysis. Using iron-based catalysts and UV
lasers, oxygen can be produced within minutes (Gondal, Hameed, Yamani, & Suwaiyan).
The present experiment produced oxygen through the reverse combustion of methane
using a catalyst and solar power. The purpose of producing oxygen in this experiment was to aid
in medical advances. Extremely preterm infants commonly have chronic lung disease, rendering
them reliant on oxygen-saturation; these infants consume more oxygen than infants without
chronic lung disease. Hospitalization is frequent and more home therapy is needed. If home
therapy can be provided for all families, it is predicted that not only will it be physically

9
beneficial for the infant, but psychologically beneficial for both the parents/caregivers and
infants, and well as convenient (Askie, Henderson-Smart, Irwig, & Simpson, 2003). In addition
to chronic lung disease, oxygen is used to reduce the risk of cognitive sequelae, a pathological
condition resulting from trauma, from carbon monoxide poisoning. Patients in this experiment
were randomly assigned to various oxygen treatments through a facemask for over twenty four
hours. After neuropsychological tests were administered, oxygen was found to reduce sequelae
(Weaver, Hopkins, Chan, Churchill, Elliot, et al., 2001). Oxygen is therefore diversely used in
the medical community to solve various conditions; in abundance, it can be administered more
frequently, helping more patients.
Most research done to reduce carbon dioxide levels has created methods in fabricating
plastics and fuels, but no literature suggests that an experiment has been done to produce oxygen
from carbon dioxide. The present research developed an experiment that decreased carbon
dioxide levels through carbon fixation using water and a catalyst. Using biological
photosynthesis as a foundation, this research investigated if carbon dioxide could be fixed to
produce oxygen and methane using solar power and a catalyst. The experimental hypothesis (HE)
stated that if a catalyst was applied to the reverse combustion of methane (CO2 + 2H2O  CH4
+2O2), then the reaction would proceed, and oxygen would be produced because the forward
reaction of the combustion of methane requires the presence of oxygen. It followed that the null
hypothesis (HO) stated that oxygen would not be produced in the reverse combustion of methane
despite the presence of a catalyst. The independent variable was the type of catalyst used, either
cadmium sulfide, zinc sulfide, or copper (II) sulfide, while the dependent variable of the study
was the amount of oxygen yielded from the reverse reaction measured in moles.

10
Although scientists have developed various methods to combat global warming, either
through green fuels or biodegradable plastics, the current research is vital as it increased the
amount of oxygen in the atmosphere while simultaneously decreased the amount of carbon
dioxide, having significant positive impact when concerning the effects of global warming on the
planet: in the air, the water, the soil, and the weather. Every year, tons of carbon pollutants are
burned for everyday necessities including, transportation, heat, air conditions, and electricity.
Most green energy options are expensive, but in dense areas where people must wear masks to
protect themselves from breathing in toxic pollutants more oxygen is necessary. Medical
conditions, asthma for example, can be a result from too many pollutants and not enough
oxygen. Aquatic ecosystems need more oxygen to survive as increased carbon dioxide levels
drastically increase the heat and acidity of the water (Munday, McCormick, & Nilsson, 2012). In
desert areas where clean drinking water crisis occur, a thriving aquatic ecosystem is vital.
Because this experiment produced both oxygen and methane, it is a contender in the battle
against climate change by two-fold. An increase in oxygen aids in medical advances as well as
returns the complex atmospheric ratio of greenhouse gases. Producing methane depletes the need
to drill and expands scientists’ abilities to create green fuels in quantity and quality as well as
helps develop new technologies. With such direct and indirect applications, this study strived to
advance environmentally friendly techniques. While the present research does not apply oxygen
and methane to these techniques, further research could utilize such advances.
METHODS OF PROCEDURE
This experiment was conducted in total over a six-month period with 80 hours of lab
work during which time the researcher collected 30 trials of data, totaling 40 samples. Methods
used during present experimentation were necessary and appropriate compared to other known

11
methods because no published literature has applied the reverse combustion of methane for
artificial photosynthesis. Standard safety protocol was used throughout the experiment and
approved by the internal review board at Oak Park and River Forest High School.
Preparation of apparatus
The apparatus was constructed using a 250 mL Erlenmeyer flask, a 550 mL Erlenmeyer
flask, and a 140 mL gas-collecting syringes from the science department at Oak Park and River
Forest High School. The researcher separately purchased a methane probe from Amazon.com.
The original design was created on a whiteboard and edited further into the present, final
apparatus which now includes solar panels, a lamp, and a stirring plate. The apparatus was
constructed under a fume hood, where the experiment took place. The lamp was plugged in and
aimed at the solar panel. The solar panel was strung through two holes in the stopper on the 550
mL Erlenmeyer flask. The ends of the wires were submerged in water. The 550 Erlenmeyer flask
rested on top of the stirring plate. The methane probe was inserted between the stopper and the
edge of the flask. A glass tube, connected to a rubber tube, was inserted into the third hole in the
stopper and submerged in water. The rubber tube, in addition to being attached to the glass
tubing, was attached to the gas-collecting syringe which held carbon dioxide.
Produced and
captured carbon
dioxide
Conducted the
reverse
combustion of
methane
Measured
methane
produced
Figure 4. This flow chart depicts a general overview of the main steps of the
procedure performed during the experiment.

12
Apparatus
A solar panel harnessed energy from a 60-watt light bulb and fueled the necessary energy
for this research. The solar panel was kept under light for the duration of the trials. A light bulb
was used as an alternative to natural sunlight because the lab area was not in direct sunlight,
causing an extrinsic variable: the light bulb allowed for constant light. The Erlenmeyer flasks
used kept the research accurate through disallowing the gas to escape through the sides and
bottom, because of the thickness of the glass. A 140 mL gas-collecting syringe from the science
department at OPRFHS was used to both measure and collect the produced gas.
As gas entered the syringe, the top of the syringe rose to make room for the gas. The
amount of gas collected was determined by the side measurements, measured from the bottom of
the indicator. Because the gas-collecting syringe allowed for three significant digits, precision
was kept. In addition, the gas-collecting syringe allowed for the gas to be transferred and
transported between equipment without letting gas escape; a stopcock was used to control the
release and storage of the gas in the syringe. Rubber stoppers, obtained from the science
department at OPRFHS, sizes 6 for the 250 mL Erlenmeyer flask and 8 for the 550 mL
Erlenmeyer flask were included to prevent gas escaping into the atmosphere, which increased the
accuracy of the research in addition to complying with lab safety by creating a seal. Rubber
stoppers were essential to the mechanics of the experiment because they come in one to four-
hole options. The third and fourth holes in the size 8 stopper were drilled in a stopper originally
containing two holes. This was necessary to accommodate for the solar panel wires that were
used in the 550 mL Erlenmeyer flask; they were submerged in water, thus creating an electrical
charge that provided the energy for the experiment. Rubber tubing was cut to 30.48 cm, and
created a passage for the carbon dioxide gas in the gas-collecting syringe to enter the reaction in

13
Figure 5. A rubber tube was attached to a
glass tube, which was inserted into a 550
mL Erlenmeyer flask so the bottomtip
was submerged in water with masking
tape. Two solar panel wires were inserted
into the flask through holes in the stopper
which were taped over. A 60-watt light
bulb lit the solar panel, and a stirring plate
and methane probe were present.The gas-
collecting syringe was attached to the
rubber tube. (Original image taken by
researcher.)
the 550 mL Erlenmeyer flask without the gas releasing. Glass tubing, cut to 13.97 cm by the
researcher using a file and a Bunsen burner, was connected to the rubber tube and allowed for the
carbon dioxide to safely pass from the rubber tube into the reaction without it escaping; it created
a channel between the surroundings and the environment. Masking tape was used to ensure a seal
between the rubber tubing and the syringe, as well as between the glass tubing and the rubber
tubing. Because the catalysts, zinc sulfide, copper (II) sulfide, and cadmium sulfide, were
insoluble in water, a stirring plate was used at 550 RPM. This ensured the catalyst’s presence and
interaction with all reactants (see Figure 5).
Carbon dioxide preparation
Before the experiment was conducted, producing and
capturing carbon dioxide was practiced. Ten trials were run
using a 250 mL Erlenmeyer flask with a size 6 single-hole
rubber stopper, and a gas collecting syringe. This apparatus was
placed in the fume hood in room 131 at OPRFHS (see Figure 6).
Trials were run by combining Market Pantry Vinegar and Arm
& Hammer Baking Soda in the 250 mL Erlenmeyer flask. The
carbon dioxide produced was collected and measured in the gas-
collecting syringe. The vinegar was measured using a glass
10.0 mL graduated cylinder and the baking soda was
measured with a balance. To ensure a complete reaction, the
researched lightly disturbed the flask when necessary
allowing for the reactants to fully interact and produce as

14
Figure 6. A gas-collecting syringe is
attached to a 250 mL Erlenmeyer flask by
a one-hole rubber stopperand is placed in
a fume hood.The researcher measured the
carbon dioxide produced from 0.500 g
NaHCO3. (Original image taken by
researcher.)
much carbon dioxide as possible. The researcher then used stoichiometry to approximate the
ideal amount of NaHCO3 (s) and CH3COOH(l) to combine. The ten trials run were recorded (see
TABLE 1). These trials helped the researcher obtain an average amount of carbon dioxide
produced to calculate the theoretical yield of oxygen and methane. The data collected and
calculated were used in the principal experiment. After each trial, the apparatus was cleaned and
rinsed with water and dried thoroughly with a paper towel.
Solar Panels
A solar panel was obtained from the science department at
OPRFHS. The solar panel had two wires. One end of each wire was
attached to the panel itself, while the opposite ends of both wires were
fed through the holes in the size 8 rubber stopper in the 550 mL
Erlenmeyer flask containing 450 mL of water and the catalyst. The
ends of the wires were submerged until the metal at the ends were
fully underwater, allowing the energy absorbed from the light bulb to
deploy into the reaction, proceeding it forward. The
amount of energy absorbed was kept constant by the 60-
watt light bulb as to prohibit other environmental
variables. The panel was kept under the light for the
duration of the experiment and an additional 10 minutes prior to running the trials. Masking tape
was placed over the wires where they were inserted through the holes in the stopper to minimize
gas escape after the carbon dioxide was administered into the 550 mL Erlenmeyer flask.

15
Figure 7. 0.10 g of CuS was measured
using a weigh boat and a balance.
(Original image taken by researcher.)
Methane probe
An AMPROBE GSD600 methane and propane detection probe was used to detect and
measure the presence of methane after the reaction took place. The probe was inserted into the
550 mL Erlenmeyer flask after it was calibrated. It recorded the amount of methane present
above 40 ppm, with a maximum ppm of 640; when methane was detected, the level at which it
was detected lit up red.
Catalysts
Three different catalysts were bought from Sigma Aldrich Company: zinc sulfide (ZnS),
99.99% purity; cadmium sulfide (CdS), 99.995% purity; and, copper (II) sulfide (CuS), 99%
purity. Each catalyst was stored in the appropriate container it was delivered in in the lab area.
Proper storage enabled the catalysts to be as pure and
uncontaminated by oxidation, in the presence of air, as possible.
Cadmium sulfide was chosen as a catalyst because previous
published research had used it in similar experiments (adapted from
Xia, Ng, An, Li, & Li et al., 2013). It has catalytic properties due to
its transition metal characteristics, as due zinc and copper.
Transition metal-based catalysts are best to use because of their lack
of reactivity, an advantage in this experiment. Cadmium sulfide is
reusable; it is easily separated from solution with a magnetic
field. Copper (II) sulfide and zinc sulfide have low toxicity,
eliminating environmental threats. 0.100 grams of each catalyst was measured with a balance
and weigh boat (see Figure 7). Each container was capped and sealed as necessary after the
proper amount of the catalyst was measured. From there, the catalyst was carefully poured into

16
the 550 mL Erlenmeyer flask, already containing 450 mL of water and the solar panel wires.
Because of the carcinogenic properties of cadmium sulfide, rubber gloves were worn to protect
the researcher from skin exposure. Each catalyst was tested in ten trials and set for comparison:
ten trials of CuS, ten trials of Cds, and ten trials of ZnS. The amount of time each catalyst took to
progress the forward reaction was recorded with a stopwatch. As soon as at least 40 ppm of
methane was detected, the amount of seconds passed was recorded (see Figure 8). If at least 80
ppm of methane was detected, the amount of seconds passed was also recorded (see Figure 9).
As soon as methane was no longer detected by the probe, the researcher stopped recording
seconds passed. After each trial, especially when changing catalysts, the apparatus was cleaned
and dried thoroughly, allowing for minimal environmental variables; and the solar panel wires
were removed and the water, catalyst, gas mixed was poured into a waste bucket for appropriate
disposal. The 550 mL Erlenmeyer flask was then rinsed with water and dried with a paper towel.
Control
The control group was tested using the 550 mL Erlenmeyer flask, as the catalysts were,
but the catalysts were omitted.
Water preparation
Tap water was used from the science department at OPRFHS. Water was used in excess,
about 450 mL measured in the 550 mL Erlenmeyer flask. After the experiment and cleaning
procedures, the Erlenmeyer flask was refilled from the same tap. Tap water, as opposed to
deionized water, was used to keep costs down as well as to create a procedure that could be used
anywhere; deionized water is not found readily in nature and may not be available in other lab
areas.

17
RESULTS
Trials
(Control)
>40 ppm
(sec)
>80 ppm
(sec)
Trials
(ZnS)
>40 ppm
(sec)
>80 ppm
(sec)
1 0 0 1 1 0
2 0 0 2 120 0
3 5 0 3 2 28
4 6.25 0 4 2 20
5 0 0 5 5 0
6 6 0 6 5 0
7 0 0 7 5 297
8 0 0 8 1 0
9 0 0 9 1 0
10 8 0 10 1 0
Trial
(CdS)
>40 ppm
(sec)
>80 ppm
(sec)
Trial
(CuS)
>40 ppm
(sec)
>80 ppm
(sec)
1 1 279 1 1 135
2 9 195 2 1 216
3 4 0 3 1 0
4 3 308 4 1 227
5 2 0 5 2 0
6 1 165 6 1 0
7 1 276 7 1 0
8 1 270 8 3 0
9 1 230 9 3 0
10 1 0 10 3 0
Trials of CO2 Production
NaHCO2 (g) CH2COOH (mL) CO2 (mL)
1.9 53.5 >500
1.9 37.5 >500
1.9 30 >500
1.9 25 >500
1.9 17 >500
1 10 129
0.5 10 73.5
0.5 10 80
0.5 10 101.5
TABLE 1. Summary of Ten Trials of Control and Experimental
Groups. With an exception of the control group, all trials reached
>40 ppm every time, and >80 ppm at least once.
TABLE 2. Trials of Carbon Dioxide Production Pre-
Procedure After 6 trials tested,it was decided that using 0.5 g
of NaHCO3, and 10 mL of CH3COOH yielded the most
constant CO2 mL.

18
Figure 8. Average Seconds Various Catalysts Produced >40 ppm of Methane
The control had the highest average seconds; it took the longest to reach >40 ppm. ZnS had the second
highest average seconds,CdS had the third highest average seconds,and CuS had the lowest average
seconds; it took the least amount of time to reach >40.
Figure 9. Average Seconds Various Catalysts Produced >80 ppm of Methane CdS had the
highest average seconds,as it reached >80 ppm more than the other catalysts.ZnS had the
second highest average seconds,and CuS had the third highest average seconds.The control
never reached >80 ppm.
0
1
2
3
4
5
6
7
8
1
Time(sec)
Catalyst
Average Seconds Various Catalysts Produced >40 ppm of Methane
Control
ZnS
CdS
CuS
0
50
100
150
200
250
300
350
1
Time(sec)
Catalyst
Average Seconds Various Catalysts Produced >80 ppm of Methane
Control
ZnS
CdS
CuS
2.556
+/- 0.6155 SEM
2.4
+/- 0.3727 SEM
1.7
+/- 0.300 SEM
6.312
+/- 1.056 SEM
24.0
+/- 7.180 SEM
246.143
+/- 39.869 SEM
192.667
+/- 30.368 SEM

19
TABLE 3. Various t-tests Comparing the Catalysts and Control The table indicates the p
value between the experimental and control groups.
t-Test: Two-Sample Assuming Unequal Variances t-Test: Two-Sample Assuming Unequal Variances
Control
>80
ZnS >80 Control
>80
CdS >80
Mean 0 34.5 Mean 0 172.3
Variance 0 8610.056 Variance 0 15895.34
Observations 10 10 Observations 10 10
Hypothesized Mean
Difference
0 Hypothesized Mean
Difference
0
df 9 df 9
t Stat 1.17575 t Stat 4.32166
P(T<=t) one-tail 0.134929 P(T<=t) one-tail 0.000964
t Critical one-tail 1.833113 t Critical one-tail 1.833113
P(T<=t) two-tail 0.269858 P(T<=t) two-tail 0.001928
t Critical two-tail 2.262157 t Critical two-tail 2.262157
2.100922 t Critical two-tail 2.100922
t-Test: Two-Sample Assuming Equal Variances t-Test: Two-Sample Assuming Unequal
Variances
Control
>40
ZnS >40 ZnS >40 CdS >40
Mean 2.525 14.3 Mean 14.3 2.4
Variance 11.14514 1382.456 Variance 1382.456 6.488889
Pooled Variance 696.8003 Hypothesized Mean
Difference
0
Hypothesized Mean
Difference
0 df 9
df 18 t Stat 1.009728
t Stat 0.99745 P(T<=t) one-tail 0.1695
P(T<=t) one-tail 0.165883 t Critical one-tail 1.833113
t Critical one-tail 1.734064 P(T<=t) two-tail 0.339
P(T<=t) two-tail 0.331766 t Critical two-tail 2.262157
t Critical two-tail 2.100922

20
t-Test: Two-Sample Assuming Unequal Variances t-Test: Two-Sample Assuming Unequal
Variances
Control
>40
CuS
>40
CdS >40 CuS
>40
Mean 2.525 1.7 Mean 2.4 1.7
Hypothesized Mean
Difference
0 Hypothesized Mean
Difference
0
df 10 df 11
t Stat 0.751706 t Stat 0.814345
t-Test: Two-Sample Assuming Equal Variances t-Test: Two-Sample Assuming Unequal
Variances
Control
>40
CdS >40 ZnS >40 CuS
>40
Mean 2.525 2.4 Mean 14.3 1.7
Pooled Variance 8.817014 Hypothesized Mean
Difference
0
Hypothesized Mean
Difference
0 df 9
df 18 t Stat 1.071282
t Stat 0.094131 P(T<=t) one-tail 0.155964
P(T<=t) one-tail 0.463022 t Critical one-tail 1.833113
t Critical one-tail 1.734064 P(T<=t) two-tail 0.311929
P(T<=t) two-tail 0.926045 t Critical two-tail 2.262157

21
t-Test: Two-Sample Assuming Unequal Variances t-Test: Two-Sample Assuming Unequal
Variances
Control
>80
CuS
>80
ZnS >80 CdS >80
Mean 0 57.8 Mean 34.5 172.3
Variance 0 9222.4 Variance 8610.056 15895.34
Hypothesized Mean
Difference
0 Hypothesized Mean
Difference
0
df 9 df 17
t Stat 1.90329 t Stat 2.78367
t-Test: Two-Sample Assuming Unequal Variances t-Test: Two-Sample Assuming Equal Variances
ZnS
>80
135 CdS >80 CuS
>80
Mean 34.5 49.2222
2
Mean 172.3 57.8
Variance 8610.06 9547.44 Variance 15895.3 9222.
Hypothesized Mean
Difference
0 Pooled Variance 12558.8
7
df 17 Hypothesized Mean
Difference
0
t Stat 0.33583 df 18
P(T<=t) one-tail 0.37055 t Stat 2.28463
t Critical one-tail 1.73961 P(T<=t) one-tail 0.01735
P(T<=t) two-tail 0.74111 t Critical one-tail 1.73406
t Critical two-tail 2.10982 P(T<=t) two-tail 0.03469
2

22
ANOVA: Single Factor
SUMMARY
Groups Count Sum Average Variance
Control >40 10 25.25 2.525 11.14514
ZnS >40 10 143 14.3 1382.456
CdS >40 10 24 2.4 6.488889
CuS >40 10 17 1.7 0.9
ANOVA
Source of
Variation
SS df MS F P-value F crit
Between Groups 1100.517 3 366.8391 1.047371 0.383442 2.866266
Within Groups 12608.91 36 350.2474
Total 13709.42 39
DISCUSSION AND CONCLUSIONS
Overall, the quantitative data (refer to Figure 8 & Figure 9) suggest that cadmium and
copper (II) sulfide efficiently produced a consistent amount of methane. Copper (II) sulfide had
ANOVA: Single Factor
SUMMARY
Groups Count Sum Average Variance
Control >80 9 0 0 0
ZnS >80 9 345 38.33333 9521
CdS >80 9 1723 191.4444 13759.03
CuS >80 9 578 64.22222 9911.194
ANOVA
Source of
Variation
SS df MS
Between Groups 185723.2 3 61907.74
Within Groups 265529.8 32 8297.806 F P-value F crit
7.460736 0.000637 2.90112
Total 451253 35
TABLE 4. Various ANOVA Tests Comparing the Catalysts and Control The table
represents the values calculated through the ANOVA statistical test. The p value is < 0.05,
signifying whether is differences between the experimental and control group comparison is
significant.

23
the lowest average when testing >40 ppm, implying that it reached >40 ppm the fastest.
Cadmium sulfide had the largest average when testing >80 ppm, implying that it reached >80
ppm most often. The ANOVA test done for the copper (II) sulfide produced a p value that was
greater than 0.05; therefore the null hypothesis was unable to be rejected, despite the fact that
raw data displayed differences. The inability to reject the null hypothesis is likely due to the
relatively small number of trials conducted. Future research would likely find more statistically
significant differences with this regard. Zinc sulfide and the control group both produced
methane, but not as efficiently or consistently. The control group did not produce any methane
over 40 ppm. The ANOVA test done for both ZnS and the control produced a p value greater
than 0.05. Figure 8 and Figure 9 were derived from data omitting extreme values: including such
values distracted from the average pattern. These values though were included in all statistics.
The ANOVA test for cadmium sulfide, tested for >80 ppm, produced a p value of
0.000637. Because this value is less than 0.05, it can be concluded that there is a statistical
significance between the control group and the cadmium sulfide tested for >80 ppm. The
experimental hypothesis can therefore be supported, and the null hypothesis can be rejected.
The results of the t-tests, derived from F-tests, (see TABLE 7) revealed that the p value
for the cadmium sulfide, for over 80 ppm, was less than 0.05. Despite being statistically
significant for greater than 80 ppm, the t-test revealed that the p value regarding cadmium
sulfide, when testing greater than 40 ppm, was greater than 0.05. These findings suggest that
cadmium sulfide was not the fastest catalyst, but it produced the greatest amount of methane.
The results of the t-test also revealed that the p value for the copper (II) sulfide when testing over
40 ppm was less than 0.05.

24
This study was conducted over 80 hours over a six-month time period with limited
resources. If additional time and resources were available, then more trials would be able to be
conducted. Anytime more trials are conducted, the statistical findings are more likely to be
significant. Another possible limitation of this study was based on experimental protocol. In
order for the methane to be measured, it was impossible to have a completely air-tight seal with
the 550 mL Erlenmeyer flask. Because of this inability, it was likely that the results were likely
impacted as methane may have escaped undetected, creating potential inaccurate data. This
likely impacted the standard deviation and the standard error. For example, the cadmium sulfide,
when testing over 80 ppm, despite it being the most effective catalyst overall, it had the greatest
standard error of +/- 39.869. This set of data had individual data points that differed significantly,
which likely led to the relatively high SEM.
The experimental hypothesis (HE) stated that if a catalyst was applied to the reverse
combustion of methane (CO2 + 2H2O  CH4 +2O2), then the reaction would proceed, and
oxygen would be produced because the forward reaction of the combustion of methane requires
the presence of oxygen. It followed that the null hypothesis (HO) stated that oxygen would not be
produced in the reverse combustion of methane despite the presence of a catalyst. It is evident
that the null hypothesis is able to be rejected based on both an ANOVA as well as individual t
tests for cadmium sulfide when testing >80 ppm compared to copper (II) sulfide. The
experimental hypothesis was supported because methane was produced and therefore it is
implied that oxygen was produced although it was not directly measured.
Efforts were made throughout the experiment to minimize potential extrinsic variables
from affecting results. All experimentation was conducted in a fume at the same temperature,
relative pressure, time of day, and by the same researcher.

25
It is interesting that the data suggests that cadmium sulfide worked as the best catalyst,
better than copper (II) sulfide and zinc sulfide. A possible explanation for this could be in the
ways that these three compounds differ: cadmium sulfide resides on a period one below both
copper (II) and zinc sulfide, therefore it has a lower ionization energy and well as a larger atomic
radius. Because of these characteristics, cadmium sulfide is more likely to be distorted by the
reactants.
This experiment specifically addressed a particular gap in the literature that does not
include the use of artificial photosynthesis, and specifically carbon fixation, to produce usable
gases. Future modifications to this apparatus could be made to create a more marketable and
accurate device capable of producing oxygen and methane gases. The potential for creating a
cost effective device that could create a carbon-neutral production process of oxygen could
prospectively be an enormous and valuable innovation for the medical field, especially in areas
of the world that do not have access to cost-effective production of oxygen for medical use.
A specific country that could benefit from such technology is Ghana. A particular
organization that supplies health care to this country is Doctors Without Borders. If this non-for-
profit company could produce oxygen more cost effectively, easily, and carbon-neutrally, more
resources would be available to fund other causes.
The positive impact of this research has the potential to extend far beyond medical uses,
and possibly include environmental advantages, such as eliminating the enormous carbon
dioxide pollution related issues. This apparatus has significant prospective to be improved upon
to be a functional prototype for a device capable of artificial photosynthesis.

26
POSITIVE IMPACT
The positive impact of this research can be applied to various components of society such
as environmental restoration, fuel production, and medicine.
With about 39.8 billions tons of carbon dioxide emitted in 2014 alone, ocean water is
becoming too hot, acidic, and too concentrated with carbon dioxide. Though it is a naturally
occurring gas in the atmosphere, an abundance of the gas is fatal to delicate ecosystems. Coral
reefs in particular are not suited to adapt to even slight temperature changes: many species of fish
living in these habitats either die or are born with defects, resulting in a higher death rate later in
life as they are no longer capable of surviving in the environment (Munday, McCormick &
Nilsson, 2012). Utilizing this experiment could potentially save millions of the different species
of fish that live in coral reefs as it used an average of 0.573 moles of carbon dioxide with only an
average cost of $120. The balanced equation for the reverse combustion of methane (CO2 + H2O
→ CH4 + 2O2) suggests that over one hundred years, 20618.02 moles of carbon dioxide will be
extrapolated from the atmosphere with a budget of $28800.00, relatively low as comparing to the
billions of dollars the Environmental Protection Agency is granted for environmental
conservation. Though seemingly small, 20618.02 moles equates to 10.00 tons, about 3% of the
39.8 billion produced in 2014. Though completely reversing the effects of carbon dioxide
pollution is impossible, regulated and returning the balance of greenhouse gases is essential to
preservation of the world’s beautiful ecosystems.
In addition to environmental concerns, this research addresses medical concerns affecting
both premature infants and the elderly. Chronic obstructive pulmonary disease (COPD) affects
three million people each year in the United States, commonly from smoking cigarrettes. This
disease is a progressive with no known cure; a treatment though is oxygen therapy. Whether it be

27
home oxygen therapy or hospitalization, most users pay 20% of the treatment, which can add up
to hundreds of dollars. This can be seen most prominently in premature infants suffering from
chronic lung disease; the infants’ lungs are underdeveloped, therefore they are susceptible to trap
air, collapse and fill with unnecessary liquid. Regular hospitalization is common for premature
infants with chronic lung disease: home oxygen therapy is not readily available, affecting
hundreds of families (Askie, Henderson-Smart, Irwig & Simpson, 2003). Decreasing the
psychological trauma and cost of rehospitalization, this research can help improve the lives of
these infants, their families, and their caretakers. 5.450 moles of oxygen were produced at only
$120.00; in bulk, my research can produce enough oxygen for home therapy.
In third world countries, premature infants and adults with chronic lung disease do not
have access to oxygen therapy without help from various organizations such as Doctors Without
Borders. The oxygen and supplies needed are expensive, but my research can directly decrease
the cost of oxygen, as it can be produced and stored cheaply; an increase in oxygen at a lower
cost can in turn aid more people who would not have access to oxygen.
Gasification is a process in which natural gas and fossil fuels are steamed to produce
electricity, hydrogen, and other products while eliminating nearly all pollutants. This experiment
produces methane, which can be used as a syngas in gasification processes for fuel. This process
is highly efficient, translating into a more economical source of energy (Kang, Seo, Jang & Seo,
2009). An increase in efficiency correlates into a decrease in necessary fuel, decreasing the
carbon dioxide output by at least forty percent. This process is used commercially in the United
States and is being further explored by the Office of Fossil Energy. With a direct source of
methane, the present research can cut the costs of methane capture, increasing the commercial
use of gasification, and therefore increasing the output of clean energy.

28
Overall, this research aids the world by threefold: supplying oxygen for the people,
decreasing the carbon dioxide for the ecosystems, and lowering the cost of fuel production. If the
findings of this research are utilized by industries and institutions in the medical and
environmental fields, the quality of life on earth can increase dramatically.

29
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