STC G5

Fig. 1. Organization of relevant and related theories and laws to the study and how they operate within the context of the present study and connect with the research’s variables

In an evolutionary world where technology has become more pioneering in the eyes of every individual, it does not alter the fact that electricity acquisition becomes circumscribed in third-world countries such as the Philippines. Around 2.4 million Filipinos experience energy and electricity scarcity due to the proliferation of consumer demands that affect the consumption of this essential commodity. Besides this drouth, another consequence that humanity has to face would be the continual man-made emissions that invite rise in the accumulation of CO2 in the atmosphere by one-half for the last 300 years and a quarter from 2000 onwards, which redounds to more energy sources to abide by the rapid urbanization of the country. Estimates say that the emanation of CO2 will augment from 0.02% to 0.25% because of the progressing civilization, industrialization, economic growth, and tourism. This instigated the construction of the following research questions:

1)What is the relationship between the electrolyzer's wattage output and the quantities of atmospheric carbon dioxide in the prototype?

2) How does the quality of the voltage produced by the electrolyzer correspond to the timeframe of its operation?

3)Does a closed environment contribute to the efficiency and effectiveness of the prototype?

4)Is the prototype effective in decreasing amounts of carbon dioxide in the closed environment?

Despite 91.4% of Filipino families having the capacity to utilize electricity, energy acquisition is still limited, specifically in Gawad Kalinga residences, as the inhabitants experience blackouts and merely depend on solar photovoltaic panels that hold inefficiency during precipitation; This also affects the environmental conditions of the Philippines, which results to health issues concerning the respiratory system.

Because of the aforementioned issues that deteriorate the economy and the environment of the Philippines, finding alternatives, such as innovating a lower-end technological device that can benefit the budget and necessities of impoverished communities, may also help in reducing CO2 emissions if the prototype is successful. It is to befit the standards of the Energy Trilemma. Furthermore, there have been gradual developments made to create CO2-derived fuels to utilize the excess carbon dioxide in the atmosphere. Such a process uses CO2 and hydrogen to create fuel containing carbon. Other forms of CO2 electrolyzers are as follows:

1) The Liquid Gallium made by the UNSW research team to capture CO2 for battery-operating systems and to convert CO2 into Oxygen (O2),

2) The Hybrid Na-CO2 cellled by Professor Kim Kun-tae to wield CO2 for electricity production and hydrogen fuel,

3) H-type electrolyzers using the liquid-diffusion method to dissolve CO2 for an electrolyte, and

4) The utilization of Tin (Sn) catalysts for electrodeposition of CO2.

Thus, the main objectives of this research are to investigate whether aluminum and copper foils as electrodes would serve their purpose of electricity generation effectively and to see any significant changes in the CO2 measured via a Dissolved CO2 sensor.

Figure 2. Procedural Framework

A summarization of the study’s step-by-step experimental procedure characterized into two main procedures: the creation of the electrolyte fluid, magnesium hydroxide, and the building of the prototype

The research is centered on investigating alternative materials for electrolysis components. The study adopts a correlational research design, refraining from variable manipulation, employing a thorough examination of statistical relationships between the study variables to identify trends. To gather relevant data, the researchers utilize time series data, repeatedly measuring the physical characteristics of key components over time. Correlational analysis, specifically Pearson's correlation and linear regression, is then applied to assess the strength and nature of the relationship between atmospheric carbon dioxide and the voltage generated by the setup. The results, visualized through scatter plots, aid in understanding whether the variables are positively, negatively, or not correlated at all.

Statistical analyses are conducted using the Jamovi software, applying Pearson's correlation to establish the relationship between atmospheric carbon dioxide and voltage generated. The suitability of this method is justified by the ratio-level measurement of both variables (CO2 in parts per million and voltage in volts) and their linear relationship. In examining the reactivity of Aluminum and Copper Foil to the alkaline solution, simple linear regression is employed. The analysis aims to determine if the CO2 yield is linearly related to voltage production. Additionally, the research employs an independent sample t-test to compare the mean voltage production on the first and second days of the electrolyzer's operation. This analysis contributes to understanding the sustainability and longevity of the electrolyzer in producing electricity. The suitability of this statistical tool is justified by the ratio-level measurement of voltage, two independent categorical groups (first and second day), and compliance with assumptions regarding normal distribution. The research emphasizes the use of properly calibrated equipment for measuring carbon dioxide and voltage, transparency in data input, and safety measures to protect researchers from material exposure. Protocols and guidance are crucial in handling electricity and voltages, ensuring safety during experimentation. Measures are also in place for proper waste disposal post-experimentation, reflecting a comprehensive ethical approach throughout the research process.

Table 1. Measures of central tendency and change of the amount of carbon dioxide and corresponding voltage generated during the first day of data collection

On the first day, the mean of CO2 and the voltage represents both the average amount of CO2 measured and amount of voltage generated by the setup. The standard deviation of CO2 is large given that the amount measured ascends, while the standard deviation of the voltage is low due to the setup's low voltage production. The setup generated a frequent amount of voltage and the decomposed paper produced a frequent amount of CO2, where both are represented by the mode.

Figure 3. The relationship between the amount of carbon dioxide and the voltage produced during the first day of data collection. Data points represent the amount of voltage produced by the measured amount of carbon dioxide.

In the scatter plot, a gap is present between the values as the plot points increase, suggesting that there are different values within the gaps. By the end of the figure, the data points indicated that they follow a pattern. As shown by the tendency of the data points to shift upward from left to right, there is a positive correlation between CO2 and voltage produced.

Table 2. Measures of central tendency and change of the amount of carbon dioxide and corresponding voltage generated during the second day of data collection

On the second day, the average level of concentration of CO2 reduced significantly. It is indicative on the central tendency table on the mean of the CO2 and voltage throughout the 15 trials of day 2. The median states the value in the middle of a data set, whereas the values that appeared often in the data during its course of time were shown by the mode of both the voltage and CO2.

Figure 4. The relationship between the amount of carbon dioxide and the voltage produced during the second day of data collection. Data points represent the amount of voltage produced by the measured amount of carbon dioxide.

In the scatter plot, the values are seen to be large and scattered with gaps between the lowest and highest values are relatively large. The CO2 is seen to have a large spread however most of the data are closely clustered with the exception of one outlier. Meanwhile, the voltage has a high disparity in the data set with its variation of results. The standard deviation of the CO2 is comparably higher than the voltage as the value ascends in the data set.

In addition, 2.5L of magnesium hydroxide was prepared to satiate its alkalinity with 2.5L of water kept at 25°C. The electrodes were then dipped inside the alkaline solution, resulting in a decrease of the liquid from day 1 to day 2 with a record of 2L of magnesium sulfate. Initially, the copper roll weighed 19.49g while the aluminum roll weighed 12.69g. As the prototype was initiated to start, the magnesium hydroxide was in contact with the electrodes and started producing heat. Due to the electrolyzers' exposure to liquid, the electrodes had absorbed some of the alkaline solution within two days, thus resulting in its mass increase. The copper had 19.86g while the aluminum had 35.17g, thus the cathode had increased in mass by 0.37g while the anode increased by 22.48g. In this experiment, the salt block is employed to conduct electricity for the light bulb through an ionic exchange between the cathode and the anode. Given that there was an oxidation-reduction reaction occurring between the electrodes on day 1, the setup produced a maximum voltage of 0.92 volts. On day 2, however, the voltage dropped to a maximum of 0.16 volts.

The results implicated the statistical significance of the experimentation conducted to determine the relationship of atmospheric carbon dioxide (CO2) and the amount of voltage produced and the significant difference of the first and second day of testing.

Table 3. Pearson’s correlation analysis between the atmospheric carbon dioxide and the corresponding voltage produced by the Cu-Al23 electrolyzer

The application of Pearson's Correlation was implemented into testing the relationship between atmospheric carbon dioxide and the amount of voltage produced by the setup. It aims to test the null hypothesis of the two variables having no relationship. On the contrary, it will test the alternative hypothesis that there is a positive correlation between both variables. The data gathered indicates a positive correlation from the alignment of increase from both the atmospheric CO2 and quantity of voltage produced, all evident in Pearson’s positive r value of 0.672. With the p-value being significantly lesser than the conventional threshold of 0.05, the null hypothesis was strongly rejected.

Figure 5. Linear regression line illustrating the relationship between the amount of carbon dioxide, measured in parts per million, and the voltage produced, measured in volts, obtained during the data collection.

Table 4. Estimates of the linear regression line’s parameters.

To test the null hypothesis that there is no linear relationship between carbon dioxide and the amount of voltage produced and the alternative hypothesis that there is a linear relationship between the variables, linear regression was applied. A statistical computer was applied to obtain the regression line equation: Voltage = -3.83 + 1.97e–5 × amount of atmospheric CO2. For every unit increase in atmospheric carbon dioxide, the voltage increased by 0.0000197 units. The collated data propounds that there is an evident linear relationship between the variables, thus rejecting the null hypothesis and accepting the alternative hypothesis.

Table 5. Independent t-test analysis of the relationship between the first and second days of observation to the amount of voltage produced.

Utilizing an independent sample t-test, it tested the null hypothesis that the first day would hold no significance to the second day (day 1 ≠ day 2) and the alternative hypothesis that there is a difference between both days of testing. Upon gathering the data, it displayed a p-value of <.001, thus rejecting the null hypothesis and elucidating the significance between both days. All of the collated results further support the use of electrode alternatives in an electrolyzer to capture carbon dioxide in order to produce electricity.

Upon the conclusion of the experimentation, the study aimed to understand and determine the relationship between the atmospheric CO2 concentration and the voltage produced. Evidence from the data tables and graphs, displayed a distinct relationship between both variables of a positive correlation which implies that as the concentration of CO2 increases, the voltage produced follows. This was further evident in the significant decrease in voltage produced from the first day to the second day due to the decreased atmospheric CO2. Unbeknownst to the researchers, an observation that was considered unexpected was the increase in mass of each electrode as it was expected to reduce due to the anode breaking apart. However, liquid absorption was the best explanation for this unforeseen outcome.

Prior work has documented and investigated the potential of CO2 electrolyzers due to their promising performance and durability in their mechanism, alongside the significance of their usage with the existence of the present climate crisis and the continuing local electricity issue. For instance, Zhao, C. and Wang, J. (2016) demonstrated the probable application of CO2 electrolyzers through Gas Diffusion Electrode-type electrolyzers by utilizing a gas-diffusion approach for transmitting CO2 to the catalyst surface and concluded that the CO2 mass exchange performance in the GDE-type electrolyzer roughly generated a greater amount of wattage compared to the H-type electrolyzer.On the other hand, a study by Kim et al. (2018) designed the Hybrid Na-CO2 cell which aimed to utilize atmospheric CO2 as the main source of fuel of the prototype for electricity production, which showed positive indications that the setup was successful in operating consistently for more than 1000 hours, and was able to produce both electricity and hydrogen (H2) gas. Although these studies have provided much input and assisted greatly in contributing to the available knowledge regarding the topic, they were unable to offer efficient, affordable, and safe materials that could be more realistically used by the mass of people in need of the kind of innovation the most.

Thus, in directing itself toward studying the potential and viability of several materials used for electricity production and the electrolyzer’s capacity as a carbon dioxide consumer, instead of an emitter, the researchers found that the electrodes, aluminum and copper foil, exhibited inefficiency and inconsistency in their performance of producing electricity due to their dissolution and oxidation. In addition, there was a significant drop in CO2 concentration during the second day, indicating the capability of the magnesium hydroxide solution to absorb significant levels of this gas, and there had been an observed significant decrease of voltage within twenty hours of the electrolyzer’s operation.

However, it is important to note certain limitations that exist within the study, such as inadequate resources and time constraints that may have contributed to the weak results yielded in the study that have hindered the total achievement of the research’s objective of creating a long-term sustainable innovation. In addition, given that the study’s design is correlational, focusing on the relationship between the concentration of CO2 and the voltage produced, it is unable to fully explore and offer other potential viable electrodes that may substitute for the copper and aluminum foil that have proven to be ineffective in facilitating the redox reaction. Nevertheless, the results obtained give an idea of the potential of the given materials in producing voltage and utilizing CO2 in line with the study’s objectives.

With these findings, further studies regarding other potential alternative materials that would present better performance are advised. As for the solution, the use of a cheaper alternative through reacting Sodium Hydroxide (NaOH) and Magnesium Sulfate (MgSO4) brought more inconvenience due to its hazardous substances and longer preparation time. Hence, it would be advantageous to have a different solution that will require lesser preparation time, lower costs, and higher CO2 absorption efficiency. Additionally, investigating external measures that can regulate the electrolyzer’s physical temperature is needed to minimize the heat produced by the solution and improve CO2 absorption. Other than this, a larger container for the solution is also recommended to provide more surface area for CO2 absorption which would result in higher produced voltages.

Moreover, an investigation for stronger and environmentally safe electrodes is vital as the ones used were prone to damage, oxidation, and dissolving. Lastly, finding other effective methods to minimize any CO2 from escaping from the enclosed environment is necessary to allow more accurate readings.

Given these, it can be concluded that the results only partially align with the objective of offering a long-term sustainable alternative source of energy to the conventional ones. While the electrolyzer can generate voltage, its output is very limited to small amounts, which is insufficient to power a small light bulb. As such, the rapid decrease in the voltage produced may also signify its low capability to produce and sustain voltage in the succeeding days. Furthermore, despite utilizing more cost-effective and accessible materials, the electrodes showed rapid deterioration. All these display both the electrolyzer’s ineffective production and inconsistent performance. On a positive note, the usage of magnesium hydroxide showed a chemical reaction upon contact with the anode, resulting in the release of gas that is assumed to be hydrogen which is non-toxic and non-corrosive.

In totality, the group was able to see the envisioned capabilities and potential of the prototype. Once scaled up and enhanced, it can offer significant benefits to different sectors that suffer from energy poverty. The further application of the concept of utilizing CO2 emissions as the main energy source presents opportunities for advancements in transportation, agricultural, and other related industries. Hence, it paves the way for innovating traditional and common methods and materials into sustainable alternatives.