Constructing SiO2-Supported Atomically Dispersed Platinum Catalysts with Single-Atom and Atomic Cluster Dual Sites to Tame Hydrogenation Performance

Construction and optimization of stable atomically dispersed metal sites on SiO2 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 SiO2 support for the first time, in which the particle size and ratio of Pt entities from single atom (Pt1) to atomic cluster (Ptn) and nanoparticle (Ptp) on the SiO2 surface were well modulated. We demonstrated the importance of dual-site synergy for optimizing the activity of single-atom catalysts. The Pt1+n/SiO2–N catalysts with the coexistence of Pt1 and Ptn showed excellent activity and optimized selectivity (99% for haloanilines) in halonitrobenzenes hydrogenation, while Pt1/SiO2–N catalysts were almost inactive in the reaction. Mechanism investigation indicates that the Ptn site is beneficial for H2 dissociation, and the Pt1 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 SiO2 support and demonstrates the significance of the synergy of dual active sites for enhancing the catalytic efficiency.