A CO2/H2fuel cell: reducing CO2while generating electricity

Abstract

Electrocatalytic conversion of CO2into hydrocarbons is one of the most promising approaches to reduce the concentration of CO2in the atmosphere as well as to produce various valuable chemical products from this most prevalent greenhouse gas. However, this process is still many steps away from finding practical application because of its high energy demand. Herein we report an innovative CO2/H2fuel cell that can convert CO2into a synthetic fuel (CH4) while generating electricity instead of consuming it. This is unlike conventional electrochemical CO2reduction cells, which typically consume electricity to reduce CO2. In the new cell, H2is oxidized to H+ions (and electrons) at the anode, and the H+ions then pass through a proton exchange membrane to reduce CO2to CH4at the cathode. While doing so, the cell can generate a current density of 94.1 A m−2, a peak power density of 3.9 W m−2and CH4at a rate of 75.29 μmol gcat−1h−1at 170 °C, a temperature that can be derived from waste heat from various processes. Density functional theory is applied to determine the reaction mechanism on the catalyst in the cell.