Effect of pH and chloroauric acid concentration on the geometry of gold nanoparticles obtained by photochemical synthesis

Rodrı́guez, Germán; Gauthier, Gilles H.; Ladeira, Luiz Orlando; Sanabria-Cala, Javier A.; Cataño, Dionisio Laverde

doi:10.1088/1742-6596/935/1/012027

Cited by 11 publications

(12 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Au NPs can be isotropic (nanospheres) or anisotropic (nanorods, nanowires, nanoshells, etc.). Au nanospheres are characterized by the presence of a single SPR band whose maximum is located at ~520 nm while their nanorod counterpart exhibits two SPR absorption bands: the transversal mode (~520 nm) and the longitudinal mode whose position depends on their aspect ratio, that is, the ratio between their length to their width [ 46 , 105 , 106 , 107 ]. During the synthesis of Au NPs, the morphology is primarily controlled by the pH of the reaction medium, precursor concentration, surfactant type, and irradiation time [ 46 , 107 ].…”

Section: Synthesis Of Gold and Silver Nanoparticles Under Uv Light Irradiationmentioning

confidence: 99%

“…Au nanospheres are characterized by the presence of a single SPR band whose maximum is located at ~520 nm while their nanorod counterpart exhibits two SPR absorption bands: the transversal mode (~520 nm) and the longitudinal mode whose position depends on their aspect ratio, that is, the ratio between their length to their width [ 46 , 105 , 106 , 107 ]. During the synthesis of Au NPs, the morphology is primarily controlled by the pH of the reaction medium, precursor concentration, surfactant type, and irradiation time [ 46 , 107 ]. To evaluate the pH influence on the formation of Au NPs, Rodriguez et al used a UV lamp (256 nm) at various pH values and many reagents, such as the precursor (tetrachloroauric acid, HAuCl 4 ; silver nitrate, AgNO 3 ), cationic surfactant (hexadecyltrimethylammonium bromide, CTAB), acids (ascorbic and hydrochloric acids), base (ammonium hydroxide), acetone, and cyclohexane [ 107 ].…”

Section: Synthesis Of Gold and Silver Nanoparticles Under Uv Light Irradiationmentioning

confidence: 99%

“…During the synthesis of Au NPs, the morphology is primarily controlled by the pH of the reaction medium, precursor concentration, surfactant type, and irradiation time [ 46 , 107 ]. To evaluate the pH influence on the formation of Au NPs, Rodriguez et al used a UV lamp (256 nm) at various pH values and many reagents, such as the precursor (tetrachloroauric acid, HAuCl 4 ; silver nitrate, AgNO 3 ), cationic surfactant (hexadecyltrimethylammonium bromide, CTAB), acids (ascorbic and hydrochloric acids), base (ammonium hydroxide), acetone, and cyclohexane [ 107 ]. As a result, Au nanospheres predominate in basic solutions (pH = 9) and their UV-Vis spectrum presents one SPR band (515 nm).…”

Section: Synthesis Of Gold and Silver Nanoparticles Under Uv Light Irradiationmentioning

confidence: 99%

“…A pH of 2.5 yielded aggregated NPs of 5–70 nm in size while a pH of 11 produced stable, uniform NPs of 18–30 nm in size [ 109 ]. This is mainly due to the rapid nucleation occurring at basic pH yielding the isotropic growth of smaller nanostructures, while the acidic pH causes the nuclei to grow anisotropically [ 107 ]. These results highlight the importance of the pH reaction medium in controlling the NP size and shape.…”

Section: Synthesis Of Gold and Silver Nanoparticles Under Uv Light Irradiationmentioning

confidence: 99%

See 3 more Smart Citations

Photochemical Synthesis of Gold and Silver Nanoparticles—A Review

et al. 2021

View full text Add to dashboard Cite

Nanomaterials have supported important technological advances due to their unique properties and their applicability in various fields, such as biomedicine, catalysis, environment, energy, and electronics. This has triggered a tremendous increase in their demand. In turn, materials scientists have sought facile methods to produce nanomaterials of desired features, i.e., morphology, composition, colloidal stability, and surface chemistry, as these determine the targeted application. The advent of photoprocesses has enabled the easy, fast, scalable, and cost- and energy-effective production of metallic nanoparticles of controlled properties without the use of harmful reagents or sophisticated equipment. Herein, we overview the synthesis of gold and silver nanoparticles via photochemical routes. We extensively discuss the effect of varying the experimental parameters, such as the pH, exposure time, and source of irradiation, the use or not of reductants and surfactants, reagents’ nature and concentration, on the outcomes of these noble nanoparticles, namely, their size, shape, and colloidal stability. The hypothetical mechanisms that govern these green processes are discussed whenever available. Finally, we mention their applications and insights for future developments.

show abstract

Section: Synthesis Of Gold and Silver Nanoparticles Under Uv Light Irradiationmentioning

confidence: 99%

Section: Synthesis Of Gold and Silver Nanoparticles Under Uv Light Irradiationmentioning

confidence: 99%

Section: Synthesis Of Gold and Silver Nanoparticles Under Uv Light Irradiationmentioning

confidence: 99%

Section: Synthesis Of Gold and Silver Nanoparticles Under Uv Light Irradiationmentioning

confidence: 99%

See 2 more Smart Citations

Photochemical Synthesis of Gold and Silver Nanoparticles—A Review

et al. 2021

View full text Add to dashboard Cite

show abstract

“…When the pH is basic, the concentration of H + ions in solution is very low, initiating fast dissociation of NADPH-dependent nitrate reductase and instantaneous reduction of a large amount of gold atoms, leading to the formation of many nuclei, which in turn leads to a higher rate of AuNPs production at pH 9. Because of this, the concentration of reduced atoms decreases and the accelerated growth of the nuclei takes place to form nanospheres, avoiding the growth of anisotropic structures [ 31 ]. Hence, more spherical AuNPs are formed at basic pH 9.…”

Section: Resultsmentioning

confidence: 99%

Crystal Growth and Kinetic Behaviour of Pseudoalteromonas espejiana Assisted Biosynthesized Gold Nanoparticles

Kumar

Das

Alkahtani

et al. 2020

Oxidative Medicine and Cellular Longevity

View full text Add to dashboard Cite

Pseudoalteromonas espejiana (P. espejiana) is a marine bacterium known for its high resistance to alkalinity. The ability of P. espejiana to reduce Au (III) and biosynthesize gold nanoparticles (AuNPs) is found positive and was confirmed using UV-VIS, EDS, SEM, and TEM studies. Previously, many studies have been reported regarding the crystalline nature of AuNPs; therefore, this research aims at studying the crystal growth behaviour of AuNPs through DLS and TEM studies. Spherically shaped and monodispersed, AuNPs ranging between 5 to 160 nm were obtained with an average particle size of 62 nm. Also, to achieve maximum production of AuNPs, the reaction kinetic study was performed using an ICP-OES method and the effect of various parameters including pH, temperature, rpm, and concentration of substrate was analyzed. During the biosynthesis process, an appropriate phase of nucleation, crystal growth, and saturation was observed and this helped to determine the rate constants and order of reaction. The parameters such as pH profile (pH 9), temperature (30°C), agitation speed (150 rpm), and enzyme substrate ratio (2 : 3) were found to be the best fits for maximum production of low size AuNPs. This demonstrates that in initial few hours, a quick conversion of the ionic gold precursor takes place into metallic gold nuclei, trailed by crystal growth via coalescence of small nuclei. Subsequently, it can be concluded that coalescence processes drive the crystal growth process of AuNPs over a time interval and finally leads to saturation and no newer particle formation in the solution.

show abstract