Effect of particle size of the Ni/SiO2 hollow spheres on the activity for reduction of 4-nitrophenol.

In this study, we investigated the effect of Ni/SiO2 hollow spheres (HS) particle size on the activity for 4-nitrophenol (4-NP) reduction. The SiO2 HS, which serves as Ni support was synthesised by sol-gel method using polystyrene (PS) particles with various diameters. TEM images show that the diameters of the SiO2 HS were 330, 445, and 490 nm. To prepare the Ni/SiO2 HS, Ni particles were immobilised by the impregnation method. SEM images of the Ni/SiO2 HS with a diameter of 330 nm show uniform spherical particles. The Ni were confirmed the surface of SiO2 HS using the EDX. Meanwhile, small particles with irregular shapes were observed in the Ni/SiO2 HS with diameters of 445 and 490 nm. The reaction for 4-nitrophenol reduction was evaluated using the obtained samples. We found that the sample with a diameter of 330 nm shows high activity. Additionally, we reveal that the SiO2 HS enhances the activity by adsorbing the 4-NP. [ABSTRACT FROM AUTHOR]