Substrate-Assisted Encapsulation of Pd-Fe Bimetal Nanoparticles on Functionalized Silica Nanotubes for Catalytic Hydrogenation of Nitroarenes and Azo Dyes

Strengthening the physical and chemical interaction between the metal and support of metal-based catalysts is one of the most effective ways to enhance their catalytic performance in heterogeneous organic catalysis. Therefore, the catalysts may possess high catalytic performance if they are designed as a confined structure, such as a metal species@support material. However, the encapsulation method usually suffers from a complicated preparation route. In this work, an encapsulated bimetallic catalyst is prepared, and its catalytic performance is evaluated in the hydrogenation of nitroarenes and azo dyes. Specifically, with the developed substrate-assisted encapsulation strategy, bimetallic Pd-Fe nanoparticles are facilely trapped between amine-functionalized silica nanotubes (SNTs) and polydopamine (PDA)-derived N-doped carbon (NC) layers. The resultant SNTs/Pd-Fe/NC bimetallic catalyst exhibits excellent catalytic efficiency toward hydrogenation of nitroarenes and azo dyes due to the unique microstructures. Typically, in catalytic reduction of 4-nitrophenol, the turnover frequency is as high as 401.28 min-1, which is the highest performance among the recently reported noble-metal nanoparticle-based catalysts. Furthermore, the current strategy is beneficial for further design and preparation of active and stable catalysts with broad applications.