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

•Ag@Pt/sepiolite catalysts were prepared by a successive reduction method.•Core-shell Ag@Pt nanoparticles were highly dispersed on sepiolite nanofibers.•The Ag@Pt core-shell structure enhanced the reduction of nitrophenols with NaBH4.•DFT calculations confirmed the contribution of Ag@Pt core-shell structure.•s-d Hybridization and charge redistribution existed between Ag cores and Pt shells.

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.

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