We present a study of electrical properties and catalytic activities of materials belonging to the hydrated carbonated system La2O3–CO2–H2O. The polycrystalline hydroxycarbonate, dioxycarbonate, and oxide are prepared via a coprecipitation route followed by heat treatment. The electrical conduction of the phases obtained by thermal decomposition from LaOHCO3, H2O is analyzed by electrical impedance spectroscopy, from 25◦ C to 950◦C, under air. The catalytic properties of LaOHCO3, La2O2CO3 and La2O3 polycrystalline phases are studied by FTIR spectroscopy, in presence of gas mixtures CO-air and CH4-air, at temperatures ranging between 100◦ C to 525◦ C. The three materials behave differently in presence of CO or CH4 gases.