Flower-shaped gold nanoparticles: Preparation, characterization, and electrocatalytic application

Al-Akraa, Islam M.; Mohammad, Ahmad M.; El‐Deab, Mohamed S.; El‐Anadouli, Bahgat E.

doi:10.1016/j.arabjc.2015.05.004

Cited by 28 publications

(9 citation statements)

References 48 publications

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“…Gold (Au) nanoparticles have attracted considerable attention, mainly because they possess exceptional stability, nontoxicity, and biocompatibility [3]. Their properties are highly dependent on the size and shape of the nanoparticles, allowing a broad range of applications [27,28]. For instance, the literature shows that gold nanoparticles in the range of 5 to 10 nm present an enhanced catalytic activity [29,30].…”

Section: Introductionmentioning

confidence: 99%

Enhanced Photocatalytic Activity of Au/TiO2 Nanoparticles against Ciprofloxacin

Martins

Kappert

et al. 2020

Catalysts

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In the last decades, photocatalysis has arisen as a solution to degrade emerging pollutants such as antibiotics. However, the reduced photoactivation of TiO2 under visible radiation constitutes a major drawback because 95% of sunlight radiation is not being used in this process. Thus, it is critical to modify TiO2 nanoparticles to improve the ability to absorb visible radiation from sunlight. This work reports on the synthesis of TiO2 nanoparticles decorated with gold (Au) nanoparticles by deposition-precipitation method for enhanced photocatalytic activity. The produced nanocomposites absorb 40% to 55% more radiation in the visible range than pristine TiO2, the best results being obtained for the synthesis performed at 25 °C and with Au loading of 0.05 to 0.1 wt. %. Experimental tests yielded a higher photocatalytic degradation of 91% and 49% of ciprofloxacin (5 mg/L) under UV and visible radiation, correspondingly. Computational modeling supports the experimental results, showing the ability of Au to bind TiO2 anatase surfaces, the relevant role of Au transferring electrons, and the high affinity of ciprofloxacin to both Au and TiO2 surfaces. Hence, the present work represents a reliable approach to produce efficient photocatalytic materials and an overall contribution in the development of high-performance Au/TiO2 photocatalytic nanostructures through the optimization of the synthesis parameters, photocatalytic conditions, and computational modeling.

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Section: Introductionmentioning

confidence: 99%

Enhanced Photocatalytic Activity of Au/TiO2 Nanoparticles against Ciprofloxacin

Martins

Kappert

et al. 2020

Catalysts

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“…Although this procedure is simple and straightforward, agglomeration of the in-situ-generated nanocatalysts is likely to occur. This shortcoming could be solved using functionalized supports which complex the metal ions before their in situ reduction into immobilized catalytic metallic nanoparticles. − In recent years, carbon nanomaterials were functionalized using a variety of methods such as the thermal treatment of azides to provide nitrenes in the presence of carbon nanotubes, Diels–Alder [4 + 2] cycloaddition, sulfonylation, and amidation …”

Section: Introductionmentioning

confidence: 99%

Bimetallic Cu–Rh Nanoparticles on Diazonium-Modified Carbon Powders for the Electrocatalytic Reduction of Nitrates

Mirzaei

Bastide

Aghajani³

et al. 2019

Langmuir

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4-benzenethiol-functionalized High Surface Area Graphite powder was prepared and decorated with bimetallic Cu 100-x Rh x nanoparticles (NPs) to serve as electrocatalysts for the reduction of nitrates. In the first step, the HSAG powder was grafted with in situ generated diazonium compounds from 4-aminothiophenol (ATP), in acidic medium using NaNO 2 for the diazotization process. The surface composition was tuned using different initial quantities of ATP. The surface XPS-determined S/C atomic ratio was found to increase stepwise with the initial amine quantity. In a second step, the grafted and untreated HSAG powders were decorated with Cu 100-x Rh x NPs by a wet chemical method and the elemental composition of the end composites assessed by EDS-SEM and ICP, whereas TEM and EDS-TEM served to characterize the NPs morphology and their composition at the nanometer scale. In all cases, the NP size was invariably found to be ~1.7 nm but with a size distribution becoming narrower under increasing grafting rate and the global composition enriched in copper. Voltammetry was performed with a cavity microelectrode to evaluate the electrocatalytic performances of the composites for nitrate reduction. Increasing diazonium grafting led to a progressive reduction of the peak current intensity and a shift of the peak potentials towards cathodic values. Maximum intensity was obtained for 0.005 µmol of diazonium salt per mg of HSAG, with a gain of 40 % in comparison to the best untreated sample. This improvement and a change of the voltammogram characteristics after grafting seem to result from modifications of the local composition at the level of NPs that differs from the global composition. This work conclusively shows that diazonium surface modification is important not only to attach electrocatalytic NPs to carbon supports but also to provide narrower size distribution of the electrocatalysts together with finely tuned catalytic properties.

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“…The electrochemical OER overpotential displayed by the two electrocatalysts (i.e., 8 = 1192 mV and 9 = 1140 mV vs. RHE) compared with commercial OER catalyst like Ru/C@390 mV versus RHE and Ir/C@380 mV versus RHE are indicative that the developed electrocatalysts requires a lot of tuning and further investigation. [ 48 ] Other than the commercial catalysts, there have been efforts in developing catalysts for OER from materials like Au‐nano particles, [ 44 ] covalent organic frameworks, [ 49 ] transition metal oxides/chalcogenides, [ 27 ] and so forth. It may be noted that this work like many others is also aimed at developing efficient, environmentally benign, abundant, economical electrocatalysts for OER.…”

Section: Resultsmentioning

confidence: 99%

Pyridine‐functionalized N‐heterocyclic carbene gold(I) binuclear complexes as molecular electrocatalysts for oxygen evolution reactions

Yhobu

Geetha

Małecki

et al. 2022

Applied Organom Chemis

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N‐heterocyclic carbene (NHC) complexes of gold(I/III) attained immense interest in catalytic organic transformations and as anticancer agents against several types of human cancers; however, their potential as electrocatalysts is scarce. The electrocatalytic oxygen evolution reaction was performed for the first time using pyridine‐functionalized NHC gold(I) binuclear metallacycles (8 and 9) possessing aptly designed ligand field. Complexes were prepared by the transmetallation of corresponding silver(I) NHC complexes, which were prepared by in situ deprotonation of pyridine and aryl substituted 1,2,4‐triazolium hexafluorophosphate salts (6 and 7) with Ag2O under dark. Both triazolium salts and binuclear gold(I) metallacycles were thoroughly characterised by NMR and ATR‐IR spectral and elemental analyses. A bromide salt 4 and a binuclear gold complex 9 were elucidated for structure by single crystal X‐ray diffraction analysis. Complex 9 possesses distorted linear coordination geometry around the gold atoms by the coordination of carbene carbon and pyridine nitrogen atoms bearing close Au–Au interaction (3.251 Å). The binuclear gold complexes 8 and 9 (along with 10 wt% conductive mesoporous carbon) were investigated as molecular electrocatalysts in oxygen evolution reaction (OER), which evidenced an oxygen evolution overpotential of 2.422 and 2.370 V versus reversible hydrogen electrode (RHE), respectively, to attain a current density of 10 mA.cm−2. The Tafel slope values of 40.9 and 30.4 mV dec−1 for 8 and 9, respectively, indicate the reaction mechanism involved and the suitability of these complexes as apt electrocatalysts for OER. The stability of the prepared molecular electrocatalysts was investigated by cyclic voltammetry and chronoamperometry techniques.

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Flower-shaped gold nanoparticles: Preparation, characterization, and electrocatalytic application

Cited by 28 publications

References 48 publications

Enhanced Photocatalytic Activity of Au/TiO2 Nanoparticles against Ciprofloxacin

Enhanced Photocatalytic Activity of Au/TiO2 Nanoparticles against Ciprofloxacin

Bimetallic Cu–Rh Nanoparticles on Diazonium-Modified Carbon Powders for the Electrocatalytic Reduction of Nitrates

Pyridine‐functionalized N‐heterocyclic carbene gold(I) binuclear complexes as molecular electrocatalysts for oxygen evolution reactions

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