ADAM PATTON
Age 18 | Kamloops, BC
Cariboo-Mainline Regional Science Fair: Engineers and Geoscientists of BC Award Cariboo-Mainline Regional Science Fair | BC Hydro Power Pioneers Award Cariboo-Mainline Regional Science Fair | Ted Rogers Communication Award Cariboo-Mainline Regional Science Fair | Michael Crooks Physics Prize Canada-wide Science Fair 2021 Excellence Award | Senior Silver Medal Canada-wide Science Fair 2021 Special Award | Senior CAP Physics Prize
Edited by Kyle D. Passley
INTRODUCTION
Hydrogen is a promising alternative fuel because it can be made using the world’s most common resource, water, through the process of electrolysis in the reaction 2 H2O → O2 + 2 H2; however, electrolysis is expensive (Hydrogen and Fuel Cell Technologies Office, n.d.). Despite the cost, platinum-based catalysts are used in the process of electrolysis because of their corrosion resistance and high efficiency. In turn, this means hydrogen produced using this method is expensive (Hydrogen and Fuel Cell Technologies Office, 2015). Currently, the cost-effective method of steam reforming (CH4 + H2O → CO + 3H2) is utilized for hydrogen production because platinum catalysts are not required in this process. Steam reforming uses hydrocarbons as a heat source and feedstock, which means that hydrogen fuel produced using this method has a carbon footprint (Hydrogen Council, 2017). This project aimed to lower the cost of electrolysis by increasing the efficiencies of commonly used, readily available, and cost-effective alternative metals through manipulating the surfaces of electrodes. In doing so, hydrogen can be produced cleanly and efficiently to replace the fossil fuels used to power everyday lives. Numerous alternative electrode shapes for electrolysis were tested using a strictly controlled experiment, and these shapes were compared to the sheet shape used commercially in three different parts. Part one tested each alternative electrode shape against the control shape in both the anode and cathode positions, allowing desirable characteristics for hydrogen production and deterioration reduction to be determined without influence from other variables. Using the results determined previously, part two focused on utilizing shapes with attributes for hydrogen production in the cathode position and shapes with attributes for deterioration reduction in the anode position to create efficient anode-cathode shape combinations. Part three explored combining multiple exemplary hydrogen production characteristics to design alternative cathode shapes.
HYPOTHESIS
Parts one and two:
If alternative electrode shapes are tested under different voltages in the process of electrolysis, and their production rates of hydrogen, deterioration rates, and power consumptions are measured, then electrode efficiencies can be increased by altering the surface properties of both electrodes to lower deterioration and increase the production of hydrogen so that readily available metals/alloys can be used in place of platinum in the process of electrolysis.
Part three:
If alternative electrode shapes are tested under different voltages in the process of electrolysis, and their production rates of hydrogen, deterioration rates, and power consumptions are measured, then alternative electrodes that combine exemplary cathode shape properties can be created to replace the traditional platinum-based electrodes used in hydrogen fuel production because of the cost-effectiveness and efficiencies of these designs.
MATERIALS & METHODS
Every metal alloy shape utilized a standard rectangle sheet control comparison. The alloys used in this project were aluminum 2025, aluminum 6061, aluminum 7075, stainless 304, brass 260, brass 360, copper 101, and copper 110. The alternative electrode shapes utilized were hexagonal bars, square bars, round bars, perforated sheets, dimple sheets, square tubes, round tubes, dimple hexagonal bars, and perforated hexagonal bars. Each alternative shape used in this project matched its control comparison in surface area and chemical composition. The weight of each electrode was recorded using a 100-gram scale for deterioration data purposes. Next, two 3 cm3 Luer-lock syringes were cut at the “1” line, and two 60 cm3 Luer-lock syringes were cut at the “60” line. Gas collectors were made by constructing a bracket-like apparatus that attached the three cm3 syringes over the 60 cm3 syringes using popsicle sticks and wood glue. Half of a cm of room was left in between the two vessels. Electrode shape/shape combinations were placed in a 25-cm tall two-litre container. The required amount of a distilled water solution for one test (e.g. two litres) was made using the ratio of 8.12 grams of sodium bicarbonate per litre of distilled water. Insulated alligator clip wires were attached to each electrode. The gas collectors made previously were placed around both the anode and cathode; the distilled water solution was poured into the container, and the collectors were sealed with Luer-lock caps, shown in figure 1.1. Using a 6-40 volt, 30-ampere pulse width modulator, alligator clips, a 6-36 volt, 30-ampere switch, and 9-volt Li-ion or NiMH batteries, the electrical circuit was made for this project. The number of batteries required to achieve the desired voltage were connected in series to the pulse width modulator using alligator clip wires. The hydrogen electrode (cathode) was attached to the negative power supply, while the oxygen electrode (anode) was attached to the positive power supply. The switch was connected in series between the pulse width modulator and the anode. The voltage and amperage setting of the pulse width modulator was verified using a multimeter. The process of electrolysis was commenced using the switch. The amount of time it took to generate one cm3 of hydrogen (in seconds) was recorded and then converted into a production rate of hydrogen (in cm3 per minute). The weight of each electrode was recorded after each trial to find deterioration per test (measured in grams).
RESULTS
Figure 1.2: Percent increases of hydrogen production rates compared to the control shape for the three best-performing cathode shapes in part one of this project. Each percent increase of hyodrogen production rate is the average taken over three different alloys. The error bars represent the variance of each dataset; each trendline is non-linear. Although the difference in the performances of the perforaded sheet cathode and hexagonal bar cathodes are insignificant, all three cathode shapes significantly increase the rate of hydrogen production compared to the control shape.
Figure 1.3: Percent increases of hydrogen production rates compared to the control shapes in part two of this project. Each percent increase of hydrogen production rate is the average taken over three different alloys. The round bar and the round tube shapes are the anodes, while the dimple sheet, perforated sheet, and hexagonal bar shapes are the cathodes. The error bars represent the variance of each dataset; each trendline is non-linear. The differences in performance for each shape combination are significant.
Figure 1.4: Percent increases of hydrogen production rates compared to the control shape in part three of this project. Each percent increase of hydrogen production rate is the average taken over three different alloys. The error bars represent the variance of each dataset; each trendline is non-linear. Both alternative cathode designs performed best when coupled with the round bar anode shape.
Figure 1.5: Percent increases of hydrogen rates compared to the control shape in all parts of this project. Each percent increase of hydrogen production rate is the average taken over three different alloys. The “x” in each bar represents the mean of the given dataset, while the horizonal line in each bar represents the median. The end of each box represents the lower and upper quartiles, the whiskers represent the range in each dataset, and the dots represent outliers. The shapes coming first in the labels are the cathodes, while the shapes coming last are the anodes. The increase in hydrogen production relative to the control for the dimple and perforated hexagonal bar designs are significantly higher than the shape combinations and singular electrode shape combinations tested in parts one and two of this project.
Figure 6: Percent reductions of deterioration per test compared to the control shape at 32 volts in all parts of this project. Each percent increase of hydrogen production rate is the average taken over three different alloys. The deterioration reduction of the round bar anode shape is significantly higher than the round tube anode shape at 32 volts in all parts of this project. The difference in the percent reductions of deterioration between parts two and three for each anode shape is insignificant, given that the uncertainties for these measurements overlap.
Part one demonstrated that cathode shapes with significant edge areas, such as hexagonal bars, dimple sheets, and perforated sheets electrolyze water with the highest hydrogen production rate of the shapes tested, shown in the percent increases of hydrogen production rates graph, figure 1.2. Part two demonstrated that coupling cathode shapes that have large edge areas with round-shaped anodes result in more efficient shape combinations. Figure 1.3 displays the percent increases of hydrogen production rates compared to the control shape for part two of this project. The dimple sheet and round bar combination increased mean hydrogen production by 21.92±0.22% at 12 volts and 16.27±0.58% at 32 volts, the hexagonal bar and round tube shape increased mean production by 20.93±0.22% at 12 volts and 14.52±0.52% at 32 volts, and the perforated sheet and round bar combination increased mean production by 17.42±0.23% at 12 volts and 13.43±0.46% at 32 volts compared to the control. The shape combinations displayed in figure 1.3 were the three best-performing combinations in terms of hydrogen production and deterioration reduction in part two of this project. Figure 1.4 shows the percent increases of hydrogen production rates compared to the control shape for part three of this project; both shape combinations displayed were the best-performing combinations tested in this project. The dimple hexagonal bar cathode design outperformed the perforated hexagonal bar cathode design at all voltages; the dimple hexagonal bar increased mean hydrogen production by 1.65±0.31% more than the perforated hexagonal bar compared to the control at 12 volts, while at 32 volts, the difference was 1.52±0.66%. As seen in figure 1.4, the dimple hexagonal bar and round bar combination increased mean hydrogen production at 12 volts by 26.01±0.15% and 17.59±0.34% at 32 volts compared to the control, while the perforated hexagonal bar and round bar combination increased mean production by 24.36±0.16% at 12 volts and by 16.07±0.32% at 32 volts. Figure 1.5 represents the percent increases of hydrogen production rates for the top-performing shapes/shape combinations in all parts of this project. Figure 1.6 displays the percent reductions of deterioration per test compared to the control shape at 32 volts for all parts of this project; the round bar and round tube shapes were the best-performing anode shapes tested. The round bar shape reduced mean deterioration at 32 volts by 63.33±1.89%, while the round tube shape reduced mean deterioration by 47.22±1.93% compared to the control. Similarly, in part three, the round bar anode shape reduced mean deterioration by 61.11±1.82% at 32 volts, while the round tube anode shape reduced mean deterioration by 44.44±2.11% compared to the control. At 12 volts, there was no detectable difference in deterioration.
DISCUSSION
This project found that coupling shapes with a large amount of edge area in the cathode position with shapes that have a minimal amount of edge area in the anode position increases the efficiency of alternative alloys to the conventional platinum-based catalysts used for commercial hydrogen production. Part one demonstrated that maximum edge area increases available surface area on electrodes by forcing off hydrogen, while minimum edge area reduces the oxide’s ability to flake off the anode, thus minimizing deterioration. As seen in figure 1.2, the three top-performing cathode shapes are similar in performance; however, the dimple sheet cathode shape significantly increased hydrogen production compared to the hexagonal bar and perforated sheet cathode shapes. From these results, part two demonstrated that cathode shapes with hydrogen production attributes can be coupled with anode shapes that have deterioration reduction attributes to maximize efficiency. Shown in figure 1.3 and figure 1.6, the dimple sheet, perforated sheet, and hexagonal bar cathode shapes coupled with the round bar and round tube anode shapes significantly increase hydrogen production and reduce deterioration compared to the control shape. Part three combined the previous results to design alternative electrode shapes for hydrogen fuel production; these electrode designs coupled cathode attributes together and proved to maximize the hydrogen production of alternative materials while minimizing deterioration, illustrated in figures 1.4 and 1.6. Throughout this project, only the anode was weighed for deterioration (decrease in electrode mass). Although both electrodes were exposed to the same environment, only the anode was exposed to oxygen; this caused the anodes to form weak, sacrificial oxides that disjoined from the electrode material, causing decreases in mass. In figures 1.2-1.4, each shape combination’s non-linear trendline approaches an unknown percent increase limit (asymptotic behaviour). As voltage increases and the electrolysis times decrease, the increases in hydrogen production become weighted less compared to the control shape’s production rate, making them less significant. Throughout this project, standard deviation decreased as the electrolysis times dropped, suggesting error related to the voltage setting of the pulse width modulator; the standard deviation and variance of each data set remained low throughout this project. Statistically, each dataset’s standard deviation and variance demonstrated that the data was accurate within >0.5 seconds; however, during data collection, each data point was rounded to the nearest whole second to account for human error in stopping the timer. After considering the standard deviation, variance, and rounding, an uncertainty of ±0.5 seconds was claimed, proving the timing method used to be accurate. Propagation of error was calculated for the production rate and deterioration comparisons; strong conclusions can be made because the uncertainty ranges for parts two and three of this project do not overlap.
CONCLUSION
The electrode designs tested in this project proved to be cost-effective and efficient alternatives to the platinum-based electrodes currently used in commercial hydrogen fuel production due to their high production rates and low deterioration rates. After testing, the hexagonal bar, dimple sheet, perforated sheet, dimple hexagonal bar, and perforated hexagonal bar electrodes were found to be the best-performing alternative shape designs for hydrogen production. Likewise, the round bar and round tube electrodes were found to be the best-performing alternative shapes for deterioration reduction. This project found that measuring time of electrolysis and deterioration per test can be used to find and design alternative shape combinations to increase the efficiency of readily available and cost-effective alloys for hydrogen production using electrolysis. In turn, the cost of electrolysis can be lowered and used efficiently over the process of steam reforming because of the ability to use alternative electrode materials to platinum.
FUTURE DIRECTION
In the future, testing more alternative shapes would be an area of focus to pursue, specifically metal foam and other round shapes. Lowering the amount of uncertainty in the measurements and more strictly measuring deterioration and controlling the dependency on other variables would allow statistical analysis to be performed on the deterioration data. Another area of focus would be to develop the experiment to support inferential statistical analysis, thereby allowing the results of this small-scale project to apply to commercial operations.
REFERENCES
“DOE Technical Targets for Hydrogen Production from Electrolysis”. (n.d.). Hydrogen and Fuel Cell Technologies Office. Retrieved February 13, 2021, from https://www.
energy.gov/eere/fuelcells/doe-technical-targets-hydrogen-production-electrolysis
“Fuel Cells”. (2015, November). Hydrogen and Fuel Cell Technologies Office. Retrieved February 13, 2021, from https://www.energy.gov/sites/prod/files/2015/11/f27/fcto_fuel_cells_fact_sheet.pdf
“Hydrogen, Scaling Up”. (2017, November 13). Hydrogen Council. Retrieved February 13, 2021, from https://hydrogencouncil.com/en/study-hydrogen-scaling-up/
ABOUT THE AUTHOR
Adam Patton
Adam Patton is a grade 12 student at St. Ann’s Academy in Kamloops, British Columbia. He enjoys problem-solving immensely and has always been interested in science, given that this was his fourth and final year competing at the Canada-wide Science Fair. This year, Adam’s goal was to increase the efficiency of alternative alloys in electrolysis by altering the surface shapes of different electrodes. His ultimate goal is to develop solutions to environmental problems that will positively impact others’ lives. Adam is enrolled at the University of Manitoba for a Bachelor of Science in Biosystems Engineering.