Abstract
Construction and optimization of stable atomically dispersed metal sites on SiO(2) surfaces are important yet challenging topics. In this work, we developed the amino group-assisted atomic layer deposition strategy to deposit the atomically dispersed Pt on SiO(2) support for the first time, in which the particle size and ratio of Pt entities from single atom (Pt(1)) to atomic cluster (Pt (n) ) and nanoparticle (Pt (p) ) on the SiO(2) surface were well modulated. We demonstrated the importance of dual-site synergy for optimizing the activity of single-atom catalysts. The Pt(1+n) /SiO(2)-N catalysts with the coexistence of Pt(1) and Pt (n) showed excellent activity and optimized selectivity (99% for haloanilines) in halonitrobenzenes hydrogenation, while Pt(1)/SiO(2)-N catalysts were almost inactive in the reaction. Mechanism investigation indicates that the Pt (n) site is beneficial for H(2) dissociation, and the Pt(1) site is energetically favorable for adsorption of the nitro group to complete the selective hydrogenation, which synergistically contributes to the optimized catalytic performances. This study provides a new strategy for constructing atomically dispersed metal species over the SiO(2) support and demonstrates the significance of the synergy of dual active sites for enhancing the catalytic efficiency.