Controlled synthesis from alginate gels of cobalt-manganese mixed oxide nanocrystals with peculiar magnetic properties

Pierre Agulhon (1) , Sandra Constant (1) , Bich Chiche (1) , Lenaïc Lartigue (1) , Joulia Larionova (1) , Francesco Di Renzo (1) , Françoise Quignard (1)

1 ICGM ICMMM - Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier

Tailored cobalt-manganese mixed oxide nanoparticles are obtained from ionotropic gels of alginate, a seaweed-derived carboxylic-functionalized polymer. (Co,Mn)3O4 phases are formed by low-temperature calcination of the alginate aerogels. Cubic spinel or tetragonal hausmannite structures are formed if, respectively, cobalt or manganese is the main cation. Stable nano-sized mixed oxides are formed in the whole range of composition of the solid solution by calcination of the aerogel precursors at 450 ◦C. The manganese-rich oxides are more dispersed than the cobalt-rich oxides, with surface areas higher than 80 m2 g−1. The organization of the oxide nanocrystals in arrays reminiscent of the fibrillar structure of the parent gel prevents them from packing and confers them peculiar magnetic properties in terms of coercivity and magnetoresistance.

Mots clés: Polysaccharide; Aerogel; Oxide

Domaines: Matériaux

Pierre Agulhon, Sandra Constant, Bich Chiche, Lenaïc Lartigue, Joulia Larionova, et al.. Controlled synthesis from alginate gels of cobalt-manganese mixed oxide nanocrystals with peculiar magnetic properties. Catalysis Today, 2012, 189 (1), pp.49-54. ⟨10.1016/j.cattod.2012.03.052⟩. ⟨hal-00694354⟩