Chem 278 Prof. Liu Research Group Seminar

 “Enhanced Gas Transport in Hybrid Bio-Inorganic CO2 and N2 Fixation Systems”

 Abstract: With the surge of intermittent, renewable electricity, the storage of excessive electricity and reduction of CO2 or N2 into value-added chemicals is of great significance for a sustainable society. One viable route is to construct a hybrid inorganic-biological system that converts electricity into chemical energy and reduces CO2/N2 into commodity chemicals. In this general approach, water is electrochemically split into H2 and O2 and the yielded H2 is consumed by microbes as a reducing equivalent for CO2/N2 reduction. This system has demonstrated high efficiencies however, the output of the commodity chemicals is limited by the supply of the reducing equivalent, H2, within the system. While we can electrochemically control the rate of H2 production, the poor solubility of H2 in the aqueous environment results in a bottleneck. Here, we demonstrate the addition of perfluorocarbon (PFC) nanoemulsions to increase H2 solubility and improve the kinetic rate of gas transport to the microbes for enhanced chemical production. With PFC nanoemulsions applied to our hybrid CO2 fixation system, we maintained nearly 100% Faradaic efficiency over a range of applied current densities and increased the throughput 2.9 times at 2.0 mA/cm2. Similarly, by adding varying percentages of PFC nanoemulsion to our N2 fixation system we were able to control the H2 and O2 concentrations in solution and enhance N2 fixation. Overall, our research demonstrates the use of PFC nanoemulsions to enhance gas solubility and gas transport in aqueous solution for favorable reaction conditions and improved rates of chemical production.