Constructing SiO<sub>2</sub>‑Supported Atomically\nDispersed Platinum Catalysts with Single-Atom and Atomic Cluster Dual\nSites to Tame Hydrogenation Performance

Construction and\noptimization of stable atomically dispersed metal\nsites on SiO<sub>2</sub> surfaces are important yet challenging topics.\nIn this work, we developed the amino group-assisted atomic layer deposition\nstrategy to deposit the atomically dispersed Pt on SiO<sub>2</sub> support for the first time, in which the particle size and ratio\nof Pt entities from single atom (Pt<sub>1</sub>) to atomic cluster\n(Pt<i><sub>n</sub></i>) and nanoparticle (Pt<i><sub>p</sub></i>) on the SiO<sub>2</sub> surface were well modulated.\nWe demonstrated the importance of dual-site synergy for optimizing\nthe activity of single-atom catalysts. The Pt<sub>1+<i>n</i></sub>/SiO<sub>2</sub>–N catalysts with the coexistence of\nPt<sub>1</sub> and Pt<i><sub>n</sub></i> showed excellent\nactivity and optimized selectivity (99% for haloanilines) in halonitrobenzenes\nhydrogenation, while Pt<sub>1</sub>/SiO<sub>2</sub>–N catalysts\nwere almost inactive in the reaction. Mechanism investigation indicates\nthat the Pt<i><sub>n</sub></i> site is beneficial for H<sub>2</sub> dissociation, and the Pt<sub>1</sub> site is energetically\nfavorable for adsorption of the nitro group to complete the selective\nhydrogenation, which synergistically contributes to the optimized\ncatalytic performances. This study provides a new strategy for constructing\natomically dispersed metal species over the SiO<sub>2</sub> support\nand demonstrates the significance of the synergy of dual active sites\nfor enhancing the catalytic efficiency.