High-temperature electrochemical heat pump using a water gas shift reaction. electrochemical reduction of CO2 to CO

The electrochemical reduction of CO2 to CO, which is considered to be the k ey reaction in a new electrochemical heat pump using the water gas shift re action, was theoretically and experimentally investigated. Thermochemical p redictions show that CO2 can be reduced to CO below -0.8 V at 973 K. It was found that the overpotential of the electrochemical reduction of CO2 to CO on a gold electrode was about 0.3 V at 0.01 mA cm(-2). Below - 1.4 V, in t he range where carbon deposition took place, CO could be produced by a chem ical reaction between CO2 and carbon. X-ray diffraction showed that the dep osited carbon was not amorphous, but graphitized carbon.