Sn-containing dendritic mesoporous silica nanoparticles (Sn-DMSNs) were successfully prepared by the in-situ co-assembly method. Sn-DMSNs preserve original structural characteristics with three-dimensional and center-radial pore structure. The nanoparticle sizes of Sn-DMSNs can be controlled systematically from 170 nm to 360 nm depending on the molar ratio of NaSal/CTAB. Sn species are incorporated into the matrix of silica and the highly dispersed SnO x species are achieved. Sn-DMSNs catalysts exhibit excellent catalytic performance and stability in the propane dehydrogenation. The highly dispersed SnO x species rather than polymeric SnO x or crystalline SnO 2 species contribute to the activation of propane and formation of propylene. The molar ratio of NaSal/CTAB also shows an important role in the structure of support and SnO x species. The excellent stability of Sn-DMSNs catalysts can be ascribed to the good ability to restrain coke formation and strong interaction between SnO x species and silica. The effect of potassium on Sn-DMSNs catalyst is also investigated.
Quan Gu,Jinlin Long,Huaqiang Zhuang,Chaoqiang Zhang,Yangen Zhou,Xuxu Wang
A variety of ternary nanoheterostructures composed of Pt nanoparticles (NPs), SnOx species, and anatase TiO2 are designed elaborately to explore the effect of interfacial electron transfer on photocatalytic H2 evolution from a biofuel–water solution. Among numerous factors controlling the H2 evolution, the significance of Pt sites for the H2 evolution is highlighted by tuning the loading procedure of Pt NPs and SnOx species over TiO2. A synergistic enhancement of H2 evolution can be achieved over the Pt/SnOx/TiO2 heterostructures formed by anchoring Pt NPs at atomically-isolated Sn-oxo sites, whereas the Pt/TiO2/SnOx counterparts prepared by grafting single-site Sn-oxo species on Pt/TiO2 show a marked decrease in the rate of H2 evolution. The characterization results clearly reveal that the synergy of Pt NPs and SnOx species originates from the vectorial electron transfer of TiO2 → SnOx → Pt occurring on the former, while the latter results from the competitive electron transfer from TiO2 to SnOx and to Pt NPs.
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