Anisotropic Gold Nanoparticle Doped Mesoporous Boehmite Films and Their Use as Reusable Catalysts in Electron Transfer Reactions

Abstract

Anisotropic Au nanoparticle (NP) doped mesoporous and oriented boehmite films of about 2 microm in thickness were prepared and used as reusable catalysts. The films were characterized by grazing incidence X-ray diffraction (GIXRD), field emission scanning electron and transmission electron microscopies, optical absorptions and surface area and pore size measurements. GIXRD of the doped films showed a preferential growth of boehmite crystallites in the (020) plane. The electron microscopy studies revealed existence of dispersed anisotropic Au NPs of approximately 15-40 nm size range and irregular Au aggregates of approximately 200-300 nm inside the mesoporous boehmite films. The optical absorption of the films showed Au-plasmon bands at 605 nm and broad absorption covering the near-infrared (NIR) region due to the anisotropic Au nanostructures. These films showed excellent catalytic activities in both the organic (p-nitrophenol to p-aminophenol by sodium borohydride) and inorganic (ferricyanide to ferrocyanide by thiosulphate) electron transfer (redox) reactions in aqueous solutions with high rate constant values. The films can be easily separated after the reaction and reused several times without any significant degradation of their original catalytic activity.

An efficient and reusable silica/dendrimer supported platinum catalyst for electron transfer reactions

“…So the obtained Pt NPs show better catalytic activity in ferricyanide system. Such result is consistent with the previous report, in which the Pt NPs based catalysts were found to be more active in ferricyanide system [35].…”

Phosphate alteration of chloride behavior at the boehmite–water interface: New insights from ion-probe flow adsorption microcalorimetry

“…Subsequently, this approach provided better insights into the nature of the Cl À /c-AlOOH interaction in the presence of phosphate. Boehmite was chosen as the model surface because of (i) its importance as a catalytic support and precursor of c-alumina (c-Al 2 O 3 ); which is one of the most common catalyst used in industrial heterogeneous catalysis [27,28], (ii) its structure and surface properties are known to be stable between pH 5-9 at room temperature [29,30], (iii) its adsorption properties [31][32][33], and (iv) its crystallography as well as hydroxyl groups that populate the exposed faces have been characterized extensively by various experimental [34][35][36][37] and mathematical modeling techniques [21,34,[38][39][40].…”

Single-Step Fabrication of Metal Nanoparticle Loaded Mesoporous Alumina through Anodizing of a Commercial Aluminum Alloy

“…9 However, uploading nanoparticles into mesoporous materials and preventing the nanoparticles from aggregation during fabrication and application processes remain a major challenge. 10,11 Here we report a single-step method for fabrication of metal nanoparticle/mesoporous alumina composite, with tuned pore morphology and particle distribution, through anodizing of a commercial aluminum alloy. The approach can easily be implemented on a large scale and extended to other alloy systems consisting of a valve metal and different alloying elements with Gibbs free energy of oxide formation less negative than that of the valve metal, having potential impacts on nanoarchitecture design and nanostructure synthesis.…”