A Comparison Reduction of 4-Nitrophenol by Gold Nanospheres and Gold Nanostars

Abstract

Abstract:In order to investigate structure-property relationships, the catalytic properties of gold nanoparticles were evaluated in the reduction of 4-nitrophenol by NaBH 4 . Using catalyst suspensions with identical amounts of gold, the following key results were obtained: first, the nanostars showed increased activity as compared to spherical gold nanoparticles; second, larger gold nanostars showed higher activity, likely because of the abundance of flat/spiky features on these particles, which show high metal utilization; third, treatment of the nanostar colloid with cucurbit [7]uril can be used to balance catalyst stability and activity; fourth, as expected from the decreasing surface atom fraction, the specific activity of the spherical nanoparticles decreased with increasing particle size.

Synthesis of Au-Pd Bimetallic Nanoflowers for Catalytic Reduction of 4-Nitrophenol

“…Typically, seed-mediated growth requires two processes: (i) the reduction of a metal precursor to form seeds with uniform and relatively small sizes; and (ii) the reduction of another metal on the as-prepared seeds. Therefore, we firstly prepared gold nanospheres (Au core, ~16 nm) [ 17 ], gold and palladium bimetallic nanoparticles (Au 1 Pd 1 core, ~20 nm) [ 20 ] and gold nanostars (~40 nm) [ 17 , 21 ] as seeds ( Figure S1 ), then palladium was reduced and deposited on these seed nanocrystals, leading to the formation of three morphology-controlled Au-Pd nanoflowers ( Scheme 1 ).…”

“…Au-Pd NFs were also tested as catalysts for the reduction of 4-nitrophenol with NaBH 4 , according to our reported procedures [ 17 ]. After the addition of NaBH 4 , the predominant species 4-nitrophenolate ion is a strong visible absorber with a maximum absorbance at 400 nm.…”

“…In our recent work, we synthesized multibranched gold nanostars by a seeded growth method. It was found that the gold nanostars presented better catalytic activity than gold nanocages and gold nanoantennas for the reduction of 4-nitrophenol (4-NP) to its amino derivative 4-aminophenol (4-AP) via sodium borohydride (NaBH 4 ) at room temperature [ 17 ]. As the degradation of 4-NP is an important reaction in fine chemicals and pharmaceutical industries [ 18 ] and can be conveniently tracked by UV-vis absorption spectroscopy, this reaction has been used to study the catalytic efficiency of numerous monometallic and alloy nanocatalysts of different sizes, shapes, and compositions [ 19 ].…”

A review of the biological synthesis of gold nanoparticles using fruit extracts: scientific potential and application

“…It has been proposed to apply GNPs synthesized from Garcinia cambogia, Lycopersicon esculentum and Prunus domestica L. as catalytic agents and colorimetric sensors [68,75,91]. The catalytic activity of GNPs is well-known [124][125][126]. The catalytic activity of the GNPs synthesized from the Garcinia cambogia L. and Prunus domestica fruit extracts against toxic 4-nitrophenol was studied [68,91].…”

Recent Advances in Nanoparticle Shape and Composition Regulation Based on Galvanic Replacement for Cancer Treatment

“…The most common examples are nanostars, sea-urchin like nanoparticles, and nanoworms, and various functionalities such as photothermal therapeutics, surface enhanced Raman scattering (SERS), and magnetic resonance (MR) imaging are possible depending on the constituent metal elements [214][215][216][217][218][219][220][221]. In general, the synthesis of anisotropic nanoparticles is controlled by regulatable molecules including solvents, surfactants, peptides, and polymers through diffusion rate and growth kinetics modulation.…”