Fabrication of SnO2-decorated Fe3O4 nanoparticles with anionic surface modification

Abstract

Core–shell-structured SnO2-decorated Fe3O4 nanoparticles were successfully synthesized by a simple solvothermal reaction. We propose an effective approach to decorate SnO2 on the Fe3O4 surface using trisodium citrate dihydrate (tSCD) and poly(acrylic acid) (PAA) as premodification materials acting as cross linkers and surface active agents. The modifications with tSCD and PAA introduced carboxyl groups on the surfaces of the Fe3O4 nanoparticles, which affected their surface charges and dispersion properties in the reaction solution. Consequently, the anionic surface modification of Fe3O4 provided uniformly decorated SnO2 nanoparticles on the Fe3O4 nanoparticles. SnO2 bound to the surface of Fe3O4 had different bonding behaviors depending on the surface modification method. The obtained Fe3O4@SnO2 (tSCD- and PAA-modified) nanocomposites had atomic ratios of Sn of 5.62% and 3.97%, respectively. The observed difference could be attributed to the bonding structures and methods using tSCD and PAA. The surface properties and SnO2 adsorption behaviors were analyzed in detail.