COMPLETE REDUCTION OF CARBON-DIOXIDE TO CARBON USING CATION-EXCESS MAGNETITE

THE reduction of gaseous oxides such as CO2 and H2O is an important concern in industrial processes and pollution control. Here we report the reduction of carbon dioxide to carbon with an efficiency of nearly 100% at 290°C using cation-excess magnetite (Fe3+δO4, δ = 0.127). In this reaction, the oxygen in the CO2 is transferred, in the form of O2-, to the cation-excess magnetite, and no gas is evolved. The carbon in the CO2 is reduced to carbon (zero valence) by the addition of an electron donated from the cation-excess magnetite to maintain electrical neutrality during the transfer of the O2- to the magnetite. When we used H2O in place of CO2, hydrogen gas was evolved, indicating that the same mechanism can also reduce H2O. © 1990 Nature Publishing Group.