Carbon dioxide reduction in a tubular solid oxide electrolysis cell for a carbon recycling energy system

A new energy transformation system based on carbon recycling is proposed called the active carbon recycling energy system (ACRES). A high-temperature gas reactor was used as the main energy source for ACRES. An experimental study based on the ACRES concept of carbon monoxide (CO) regeneration via high-temperature reduction of carbon dioxide (CO2) was carried out using a tubular solid oxide electrolysis cell employing Ni-LSM cermet|YSZ|YSZ-LSM as the cathode|electrolyte|anode. The current density increased with increasing CO2 concentration at the cathode, which was attributed to a decrease in cathode activation and concentration overpotential. Current density, as well as the CO and oxygen (O2) production rates, increased with increasing operating temperature. The highest CO and O2 production rates of 1.24 and 0.64 μmol/min cm2, respectively, were measured at 900 °C. Based on the electrolytic characteristics of the cell, the scale of a combined ACRES CO2 electrolysis/iron production facility was estimated.