Entrapment and stabilization of iron nanoparticles within APTES modified graphene oxide sheets for catalytic activity improvement

In this work, for the first time, a grafting of 3-aminopropyltriethoxysilane (APTES) followed by incorporation of iron nanoparticles (Fe-NPs) was used for the functionalization of graphene oxide (GO). Changes in stability, structural, morphological, thermal and catalytic properties of the resulting GO/APTES/Fe material were investigated by scanning electron microscopy, transmission electron microscopy, energy dispersive X-Ray, Fourier transform infrared and UV-visible spectroscopies, zeta potential measurements, X-ray photoelectron spectroscopy and differential scanning calorimetry. The average crystallite size of GO/APTES/Fe was found to decrease significantly after the post treatment, producing slight structure compaction. Iron nanoparticles were immobilized by APTES on the GO sheets, with a particle size around 50 nm. Fe insertion and APTES grafting resulted in high thermal stability of GO. As an application, GO/APTES/Fe exhibited an excellent catalytic activity in the reduction of 4-nitrophenol into 4-aminophenol. The presence of both APTES and small amount of Fe nanoparticles in GO/APTES/Fe induced a significant improvement in catalytic activity. GO/APTES/Fe also showed appreciable recyclability after four repeated uses without noticeable loss in activity. This stability was higher to those of other GO-materials. The results obtained herein open new prospects for Fe-loaded organo-graphene oxide as efficient material in catalysis and industrial applications. (C) 2018 Elsevier B.V. All rights reserved.