Direct synthesis of mesoporous Fe3O4 through citric acid-assisted solid thermal decomposition

A simple and inexpensive approach to synthesizing mesoporous Fe3O4 is developed by using citric acid-assisted solid thermal decomposition of ferric nitrate. The structure and magnetic property of mesoporous Fe3O4 were characterized by XRD, FT–IR, N2 adsorption–desorption isotherms, TEM, and vibrating sample magnetometer. It was shown that the decomposition of citric acid results in the formation of the mesoporous structure and narrow pore-size distribution. The reducing atmosphere which created by the decomposition of the ferric nitrate–citric acid complex caused the partial reduction of Fe(III) to Fe(II) and in turn the formation of Fe3O4. Moreover, the strength of the coordination between carboxyl group and Fe3+ also affected the phase composition of the iron oxides.