Josh Grilly

Ph.D. Pre-Candidate
Chemical Engineering

jgrilly@umich.edu

Current scientific evidence links anthropogenic carbon dioxide generation with global climate change. As such, the National Academy of Engineering lists the remediation of atmospheric CO₂ as one of the Grand Challenges of the 21^st century. One option for dealing with excess CO₂ is sequestration. Another option is to recycle the CO₂ into useful products. My project focuses on the latter option by electrochemically reducing CO₂ into various hydrocarbon products.

CO₂ is a very stable molecule at ambient conditions. It can, however, react with a strong reductant such as hydrogen. Thermodynamically favorable products include methane, ethane, methanol, and ethanol. Traditional chemical processes require high temperature, reducing the efficiency of the process. The electrochemical process can be carried out at ambient conditions. However, a large overpotential is required and the product distribution varies wildly. Thus the challenge is to develop catalyst materials and a reaction system that allow for an efficient reduction of carbon dioxide into useful carbon-containing products.

Our reactor is run as a fuel cell in reverse: hydrogen is fed on one side of the cell. The hydrogen dissociates and diffuses across a Nafion proton-exchange membrane, where it reacts with carbon dioxide to form hydrocarbon products. We are looking at catalysts that will more effectively facilitate the formation of desirable products.

Apparent standard potentials vs. pH for CO2 reduction

Simplified setup for continuous flow CO2 reduction