Core-Shell Au@SnO Nanostructures Supported on NaTiO Nanobelts as a Highly Active and Deactivation-Resistant Catalyst toward Selective Nitroaromatics Reduction.

Catalysis using gold (Au) nanoparticles has become an important field of chemistry. However, activity loss caused by aggregation or leaching of Au nanoparticles greatly limits their application in catalytic reaction. Herein, we report a facile and green synthesis of a core-shell Au@SnO nanocomposite, exhibiting excellent activity toward selective nitroaromatics reduction under mild conditions. The core-shell Au@SnO nanocomposite (Au size = ∼50 nm; shell thickness = ca. 16 nm) is conceived and validated by a direct redox reaction between HAuCl and SnF. Optimization of the core size, shell thickness, and dispersion of Au@SnO has been introduced by an alkaline surface supported by negatively charged metal oxide NaTiO. The as-obtained Au-Sn-NaTiO catalyst with much smaller Au cores (ca. 5 nm) and thinner SnO nondensed shells (ca. 4 nm) exhibits highly improved catalytic activities for nitro reduction compared to most of the known Au-based catalysts. Moreover, the core-shell Au@SnO structure inhibits the leaching and agglomeration of Au nanoparticles and thus leads to superior catalytic durability.