A CO₂/H₂fuel cell: reducing CO₂while generating electricity

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 g_cat⁻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.