One-Pot Green Synthesis of Ag-Decorated SnO Microsphere: an Efficient and Reusable Catalyst for Reduction of 4-Nitrophenol.

In this paper, hierarchical Ag-decorated SnO microspheres were synthesized by a facile one-pot hydrothermal method. The resulting composites were characterized by XRD, SEM, TEM, XPS, BET, and FTIR analysis. The catalytic performances of the samples were evaluated with the reduction of 4-nitrophenol to 4-aminophenol by potassium borohydride (KBH) as a model reaction. Time-dependent experiments indicated that the hierarchical microspheres assembled from SnO and Ag nanoparticles can be formed when the react time is less than 10 h. With the increase of hydrothermal time, SnO nanoparticles will self-assemble into SnO nanosheets and Ag nanoparticles decorated SnO nanosheets were obtained. When evaluated as catalyst, the obtained Ag-decorated SnO microsphere prepared for 36 h exhibited excellent catalytic performance with normalized rate constant (κ ) of 6.20 mingL, which is much better than that of some previous reported catalysts. Moreover, this Ag-decorated SnO microsphere demonstrates good reusability after the first five cycles. In addition, we speculate the formation mechanism of the hierarchical Ag-decorated SnO microsphere and discussed the possible origin of the excellent catalytic activity.