Optical properties determination of NiFe2O4 nanoparticles and their photocatalytic evaluation towards hydrogen production

At present, the synthesis of active photocatalytic materials under visible light is a challenge to be considered in technologies involved in hydrogen production through photocatalytic water splitting. The spinel-type transition metal ferrites (MFe2O4), unlike the widely used TiO2, show remarkable activity under visible light, which makes them promising candidates for future applications on photocatalytic reactors. In the present research, nanoparticles of NiFe2O4 were synthesized by the modified Pechini's method and their structural, morphological, textural and optical characterization were carried out through thermogravimetric analysis, X-ray diffraction, scanning electron microscopy, BET surface area, and UV/Vis spectroscopy. Optical properties (absorption and scattering coefficient) were determined using aqueous suspensions of NiFe2O4 nanoparticles at several concentrations. Furthermore, an evaluation of its photocatalytic activity for hydrogen production under visible light was carried out by means of gas chromatography, finding a greater hydrogen production of NiFe2O4 than that of TiO2 at the same experimental conditions.