To begin my research this summer, I conducted a literature review of the experimental methods being used by scientists to capture or convert carbon dioxide using electrocatalysis, particularly ones involving nanoparticles. These past few weeks, I have been studying the data analysis methods used in these papers, and understanding how the formulas they used to produce their data work.
I read papers on various other types of semiconductor catalysis for the electroreduction of carbon dioxide. The most stable choice with high efficiency overall seems to be bimetallic copper-based catalysts, like the ones I grew and am experimenting with. Growing these catalysts on the scale of nanometers increases the number of “gaps” meaning that more catalysis reactions occur.
An important factor to consider is the desired product of the electroreduction. Some of the most common products produced by electrocatalysis for carbon dioxide are carbon monoxide, formic acid, methanol, and hydrogen gas. These are all chemicals that are essential to many industrial processes and can be reused in those, or liquid fuels. I suspect that all of these products will be produced from the electrocatalysis, but analysis will have to be performed on the gas products by hooking the reactor up to a gas chromatography machine (GC) and by taking the liquid products to a nuclear magnetic resonance (NMR) machine to characterize them.
There are numerous data analysis methods used to produce numbers that measure how well the nanocatalyst works. Once I acquire my raw data, I plan on finding the Tafel slope, which is a measure of how much you have to increase the overpotential to get a tenfold increase in reaction rate. You would want the overpotential (the difference between potential applied experimentally and the standard reduction potential of the reaction occurring) to be as little as possible for greater efficiency. I also plan to measure the current density (total current applied over the area of the electrode) which you would want to be as high as possible at lower values of overpotential for the nanocatalyst to be efficient. Finally, the Faradaic efficiency is one of the most important numbers I will calculate from my raw data, as it shows not only what percent of the carbon dioxide was converted, but also the proportions of each product it produced. This would show how the nanocatalysts I grew via colloidal synthesis are more or less selective for the production of a particular new chemical.