CO2-to-Formate Storage Cell Project

ISEF Category: Energy: Sustainable Materials and Design

Subcategory: Energy Storage  ·  Difficulty: Advanced  ·  Setup: School Lab  ·  Time: Full Year

The Hook

Carbon dioxide is not just a climate gas. It can also become a liquid fuel building block. Your job is to see how well a tin cathode turns CO2 into formate, then measure how much of the electrical input ends up in that product. That means you are not just making bubbles. You are tracking energy storage.

What Is It?

This project studies electrochemical CO2 reduction. That sounds huge, but the idea is simple. You use electricity to push CO2 into a new chemical form. In this case, the target product is formate, a small carbon-containing ion that can act like a storable chemical fuel or feedstock.

Think of the cell like a sorting machine. The electricity is the push, CO2 is the raw material, and the tin cathode is the surface where the reaction happens. A good cathode sends more of the electrical input toward formate and less toward side reactions like hydrogen gas. Faradaic efficiency tells you that split. It answers, “What fraction of the current actually made the product I want?”

The USB pH/conductivity probe gives you useful signals about what the electrolyte is doing during the run. pH can shift as reactions consume or release ions. Conductivity can change as ions move around or products build up. Those signals do not directly prove formate, but they help you compare runs and spot when the cell behavior changes.

Why This Is a Good Topic

This is a strong science fair topic because you can vary one clear design choice, then measure how well the cell performs. You can compare tin foil against another cathode shape, surface treatment, or electrolyte condition. The project connects to carbon capture, renewable electricity storage, and chemical manufacturing, which gives it real-world value. You can also learn electrochemistry, data analysis, and how to judge whether a signal actually means better performance.

Research Questions

• How does tin foil surface roughness affect Faradaic efficiency for CO2-to-formate conversion?
• What is the effect of electrolyte pH on the conductivity and pH change during CO2 electroreduction?
• Does changing the cathode geometry alter the balance between formate production and side reactions?
• To what extent does current density change the stability of the CO2-to-formate cell over repeated runs?
• Which electrolyte composition gives the largest conductivity shift during operation while keeping the cell stable?
• How does pre-treating the tin cathode affect repeatability of the measured pH and conductivity signals?

Basic Materials

• Tin foil cathodes
• Carbon or graphite counter electrode
• Reference electrode if your setup uses one
• DC power supply or potentiostat
• Beaker or electrochemical cell
• CO2 source or gas cylinder with regulator, if available through school
• Aqueous electrolyte solution chosen for your protocol
• USB pH probe
• USB conductivity probe
• Digital multimeter
• Clamp stand and electrode holders
• Magnetic stir plate and stir bar
• Distilled or deionized water
• Digital balance with 0.01 g resolution
• Timer
• Safety goggles and nitrile gloves.

Advanced Materials

• Potentiostat with chronoamperometry and cyclic voltammetry capability
• Gas-tight electrochemical cell
• Tin foil, tin-coated substrates, and control cathodes
• Ag/AgCl reference electrode
• Gas flow controller or rotameter
• Inline gas trap or collection system
• Ion chromatography access for formate confirmation
• HPLC or NMR access for product validation
• pH microelectrode and conductivity probe
• Data acquisition interface
• Analytical balance with 0.001 g resolution
• Fume hood access
• Calibration buffers and conductivity standards
• Computer for electrochemical analysis.

Software & Tools

• Python: Fits calibration curves, processes probe data, and compares cell runs.
• Google Sheets: Organizes trial data and calculates averages, spread, and percent change.
• ImageJ: Measures and compares cathode surface texture from phone or microscope images.
• R or Jamovi: Runs statistical tests and helps compare treatment groups.
• LabArchives: Keeps a clean experiment log, notes, and raw data in one place.

Experiment Steps

1. Define the product signal you will trust, and decide how you will separate true performance from background drift.
2. Choose one main variable, such as cathode surface state, electrolyte choice, or current setting, and keep the rest fixed.
3. Plan a control set that lets you compare CO2 exposure against a non-CO2 condition and a blank electrode condition.
4. Build a measurement plan that links probe readings, current data, and product confirmation into one dataset.
5. Select a calibration strategy so you can turn raw probe output and electrochemical readings into comparable numbers.
6. Set your statistics plan before you start, including how many repeats you need and how you will judge a real effect.

Common Pitfalls

• Assuming a pH shift proves formate formation, which can make you confuse electrolyte drift with product yield.
• Letting the tin foil surface change between trials, which can change reaction behavior more than the variable you meant to test.
• Skipping product confirmation, which leaves you with conductivity and pH data but no direct proof of formate.
• Using inconsistent CO2 delivery, which changes gas availability and makes current data hard to compare.
• Collecting too few repeats, which makes noise look like a real improvement.

What Makes This Competitive

A stronger project will not just ask whether the cell works. It will compare several cathode treatments, back the claims with calibration data, and use statistics that can separate signal from noise. You can also strengthen the work by pairing electrochemical measurements with an independent formate check, not just pH and conductivity. That kind of design shows you understand both the chemistry and the measurement limits.

Project Variations

• Test how sanding, polishing, or oxide removal on tin foil changes CO2 reduction performance and signal stability.
• Compare tin foil with tin-coated copper, graphite, or stainless steel as the cathode material.
• Study how changing electrolyte pH or salt choice shifts conductivity, current response, and formate-related performance.

Learn More

• NIH PubMed: Search for review articles on electrochemical CO2 reduction, formate production, and Faradaic efficiency.
• NASA Earthdata: Find background on atmospheric CO2, carbon cycling, and climate data for project motivation.
• DOE Office of Science: Read public explanations of carbon conversion, electrochemistry, and energy storage research.
• MIT OpenCourseWare: Search for free lecture notes on electrochemistry and chemical thermodynamics.
• USGS Water Science School: Review clear explanations of conductivity, ions, and water chemistry measurements.