Beneficial effects of substituting trivalent ions in the B-site of La(0.5)Sr(0.5)Mn(1-x)A(x)O(3) (A = Al, Ga, Sc) on the thermochemical generation of CO and H-2 from CO2 and H2O

Abstract

The effect of substitution of Al3+, Ga3+ and Sc3+ ions in the Mn3+ site of La0.5Sr0.5MnO3 on the thermochemical splitting of CO2 to generate CO has been studied in detail. Both La0.5Sr0.5Mn1-xGaxO3 and La0.5Sr0.5Mn1-xScxO3 give high yields of O-2 and generate CO more efficiently than La0.5Sr0.5Mn1-xAlxO3 or the parent La0.5Sr0.5MnO3. Substitution of even 5% Sc3+ (x = 0.05) results in a remarkable improvement in performance. Thus La0.5Sr0.5Mn0.95-Sc0.05O3 produces 417 mu mol g(-1) of O-2 and 545 mu mol g(-1) of CO, respectively, i.e. 2 and 1.7 times more O-2 and CO than La0.5Sr0.5MnO3. This manganite also generates H-2 satisfactorily by the thermochemical splitting of H2O.