Use of SBA-15 silica grains for engineering mixtures of oxides CoFe and NiFe for Advanced Oxidation Reactions under visible and NIR

The fabrication of nanomaterials for specific applications, for plants protection and ameliorated production is an important and fast growing research field. In the present work, particularly small nanoparticles of several oxides were dispersed on SBA-15 silica mesoporous grains starting from metallic chlorides (Co, Ni, Fe). Samples were labelled NiFe_700_SBA-15 and CoFe_700_SBA-15, with 700 corresponding to the used calcination temperature. Characterizations were performed by X-ray fluorescence, XRD and TEM associated with EDS and SAED. Three main kinds of oxides were identified: 1) Co₃O₄ and NiFe₂O₄ bulk nanoparticles of structure close to magnetite (cubic, with one M(II) for two Fe(III) cations), 2) defect containing nanowires of CoFeO₃, 3) Ni_0.5Fe_0.5O. UV–vis measurements were performed to demonstrate that the prepared mixtures were able to absorb light in the visible (and the NIR) spectral ranges. The developed NiFe_700_SBA-15 and CoFe_700_SBA-15 mixtures were successfully tested for the heterogeneous photocatalytic oxidation of a pesticide, carbendazim. In the used experimental conditions, an Aeroxide titania P25 reference (EVONIK®) was found poorly active only and the activity measured with CoFe_700_SBA-15 was better than the one of NiFe_700_SBA-15.