Abstract: The present invention concerns a nano-structured composite material based on compositions of manganese and cerium, composed of aggregated composite nanospheres, ranging in size from 1 to 40 nm, of ultrafine crystalline nanoparticles of one or more compounds of cerium, dispersed in a metastable solid mixture of one or more sub-stoichiometric oxides of manganese, said sub-stoichiometric oxides of manganese comprising MeMnOz manganates, wherein 1?z?4, Me being constituted of one or more elements selected amongst alkali metals, alkaline earth metals, transition metals and rare earths, and in particular being constituted of one or more elements selected amongst Ce, V, Ti, Cr, Fe, Cu, Zn, Sn, Ga, Gd, Y, Zr, Al, Si, La, K, Li, Pb, Cs, or mixtures thereof; which can be used in the industry as redox catalyst and/or adsorbing filter of heavy metals, cyanides, sulfur compounds, pigments, dyes, polymers (PEG), phenols, alcohols, aldehydes and ketones, ethers, esters and carboxylic acids which are present both in contamin