Beneficial effects of substituting trivalent ions in the B-site of La0.5Sr0.5Mn1−xAxO3 (A = Al, Ga, Sc) on the thermochemical generation of CO and H2 from CO2 and H2O

Abstract

The effect of substitution of Al³⁺, Ga³⁺ and Sc³⁺ ions in the Mn³⁺ site of La_0.5Sr_0.5MnO₃ on the thermochemical splitting of CO₂ to generate CO has been studied in detail. Both La_0.5Sr_0.5Mn_1−xGa_xO₃ and La_0.5Sr_0.5Mn_1−xSc_xO₃ give high yields of O₂ and generate CO more efficiently than La_0.5Sr_0.5Mn_1−xAl_xO₃ or the parent La_0.5Sr_0.5MnO₃. Substitution of even 5% Sc³⁺ (x = 0.05) results in a remarkable improvement in performance. Thus La_0.5Sr_0.5Mn_0.95Sc_0.05O₃ produces 417 μmol g⁻¹ of O₂ and 545 μmol g⁻¹ of CO, respectively, i.e. 2 and 1.7 times more O₂ and CO than La_0.5Sr_0.5MnO₃. This manganite also generates H₂ satisfactorily by the thermochemical splitting of H₂O.