AuPd Bimetallic Nanocrystals Embedded in Magnetic Halloysite Nanotubes: Facile Synthesis and Catalytic Reduction of Nitroaromatic Compounds

Abstract

In this research, a facile and effective approach was developed for the preparation of well-designed AuPd alloyed catalysts supported on magnetic halloysite nanotubes (HNTs@Fe3O4@AuPd). The microstructure and the magnetic properties of HNTs@Fe3O4@AuPd were confirmed by transmission electron microscopy (TEM), high resolution TEM (HRTEM), energy-dispersive X-ray spectroscopy (EDS), and vibrating sample magnetometry (VSM) analyses. The catalysts, fabricated by a cheap, environmentally friendly, and simple surfactant-free formation process, exhibited high activities during the reduction of 4-nitrophenol and various other nitroaromatic compounds. Moreover, the catalytic activities of the HNTs@Fe3O4@AuPd nanocatalysts were tunable via adjusting the atomic ratio of AuPd during the synthesis. As compared with the monometallic nanocatalysts (HNTs@Fe3O4@Au and HNTs@Fe3O4@Pd), the bimetallic alloyed HNTs@Fe3O4@AuPd nanocatalysts exhibited excellent catalytic activities toward the reduction of 4-nitrophenol (4-NP) to 4-aminophenol. Furthermore, the as-obtained HNTs@Fe3O4@AuPd can be recycled several times, while retaining its functionality due to the stability and magnetic separation property.

Enhanced Catalytic Reduction of 4-Nitrophenol Driven by Fe3O4-Au Magnetic Nanocomposite Interface Engineering: From Facile Preparation to Recyclable Application

“…Especially, Au nanoparticles (NPs) have been intensely explored because of their unique and tunable optical properties and high catalytic activities [ 15 , 16 , 17 , 18 , 19 ]. Compared to the semiconductor photocatalysts, noble metal catalysts possess higher catalytic activity with respect to organic pollutants [ 20 , 21 , 22 , 23 , 24 ]. Typically, Au NPs have been intensely employed for the catalytic reduction of a variety of organic pollutants [ 25 ].…”

Liquid Phase Hydrogenation of Pharmaceutical Interest Nitroarenes over Gold-Supported Alumina Nanowires Catalysts

“…Some strategies consider the preparation of nanometric catalysts, obtained from core-shell (0D) structures that include in their design the insertion of the active phase in the core [20][21][22] or the Shell [23]. Other reported strategies include the preparation of supported catalysts by the deposition of Au in support via 1D arrangements (nanotubes, nanowires) [18,[24][25][26], 2D (graphene sheets, clays) [27][28][29], or in 3D structures such as mesostructured silicas [16,30,31], carbonaceous supports [32][33][34] and others.…”

Halloysite Nanotubes for Cleaning, Consolidation and Protection

“…As concerns covalent modifications, the organosilanes grafting onto the HNTs outer surface allowed to synthesize efficient supported catalysts for polymerization of methyl methacrylate . Beside pristine HNT, modification of HNTs shell via aminosilane was conducted to bind metals (Au, Pd, Pt, Rh) . On the other hand, inorganic micelles able to entrap hydrophobic compounds were obtained by binding octadecylphosphonic acid and dopamine derivatives, to alumina groups of the HNTs cavity.…”