Effect of CaCO3 addition on the electrochemical generation of syngas from CO2/H2O in molten salts

A novel green method was presented for the simultaneous synthesis of syngas, a mixture of CO and H-2, via the co-electrolysis of CO2/H2O using an established eutectic-salt electrolyte. Optimum electrolysis was carried out at 2.2 V using a two-electrode system composed of a coiled Fe cathode and a coiled Ni anode in eutectic Li1.07Na0.75Ca0.045CO3/0.15LiOH. The molar ratio of H-2/CO was finely tuned from 1.96 to 7.97 by controlling the amount of CaCO3. The optimized current efficiency, similar to 92%, was acquired by 14.28 wt% CaCO3 addition. Moreover, the relatively low operating temperature of 600 degrees C was beneficial for practical applications compared to previously reported temperatures in excess of 800 degrees C, providing a feasible basis for syngas production via electrochemical synthesis. In this manner, CO2/H2O was synergistically converted into valuable chemicals, allowing the CO2 to be utilized efficiently for the conversion and storage of electricity to chemical energy. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.