Core-shell Ag@Pt nanoparticles supported on sepiolite nanofibers for the catalytic reduction of nitrophenols in water: Enhanced catalytic performance and DFT study

We reported the enhanced catalytic property of core-shell Ag@Pt nanoparticles supported on sepiolite nanofibers for the reduction of nitrophenols in the presence of NaBH4. Furthermore, we confirmed the contribution of core-shell structure to the enhanced catalytic performance of Ag@Pt nanoparticles by DFT calculations. The Ag@Pt/sepiolite catalysts were prepared using a successive reduction method, in which core-shell Ag@Pt nanoparticles were highly dispersed on sepiolite nanofibers. DFT calculations showed that the charge redistribution and s-d hybridization between Ag cores and Pt shells contributed to the unique electronic structure of Ag@Pt nanoparticles. More importantly, 2 wt.% Ag@Pt/sepiolite catalyst exhibited much higher catalytic activity toward nitrophenols reduction than Ag/sepiolite and Pt/sepiolite, and relatively high catalytic stability even after 5 cycles. The enhanced catalytic performance of Ag@Pt/sepiolite catalysts was primarily owing to the large surface area and high porosity of sepiolite nanofibers and the unique electronic structure of core-shell Ag@Pt nanoparticles, which resulted in the effective adsorption of nitrophenols and the electron transfer from BH4- to nitrophenols, respectively. This study probably provides new insights into the catalytic reduction of nitrophenols in water by forming the composite between bimetallic core-shell nanoparticles and natural low-cost supports. (C) 2016 Elsevier B.V. All rights reserved.