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One-Step Green Synthesis of Gold Nanoparticles Using Black Cardamom and Effect of pH on Its Synthesis.

Singh AK, Srivastava ON - Nanoscale Res Lett (2015)

Bottom Line: The black cardamom extract is used as a reducing agent for HAuCl4.3H2O.Based on Fourier transform infrared spectroscopy (FTIR) studies, a tentative mechanism of reduction of Au nanoparticles has also been proposed which includes oxidation of 1,8-cineole to 2-oxo-1,8-cineole.Further, a comprehensive study to investigate the effect of pH on the synthesis of Au nanoparticles has been carried out.

View Article: PubMed Central - PubMed

Affiliation: DST Unit on Nanoscience and Technology, Department of Physics, Banaras Hindu University, Varanasi, 221005, India, ashwanikumarsingh143@gmail.com.

ABSTRACT
In the present article, an effective, one-step, and environmentally benign protocol for the synthesis of gold nanoparticles has been discussed. The black cardamom extract is used as a reducing agent for HAuCl4.3H2O. In order to synthesize gold nanoparticles, an aqueous solution of HAuCl4.3H2O was mixed with an optimized concentration of black cardamom extract where 1,8-cineole is the dominant component. Choosing black cardamom extract as a reducing agent can be justified under the light of the fact that it has a very fast reducing ability. Gold nanoparticles with different shapes and sizes were synthesized by varying the ratio of AuCl4 ions to black cardamom extract. Kinetics of reactions has been evaluated through monitoring of surface plasmon behavior of gold nanoparticles as a function of time. Based on Fourier transform infrared spectroscopy (FTIR) studies, a tentative mechanism of reduction of Au nanoparticles has also been proposed which includes oxidation of 1,8-cineole to 2-oxo-1,8-cineole. Further, a comprehensive study to investigate the effect of pH on the synthesis of Au nanoparticles has been carried out.

No MeSH data available.


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a–f Transmission electron micrograph of synthesized gold nanoparticles
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Fig3: a–f Transmission electron micrograph of synthesized gold nanoparticles

Mentions: After a careful investigation of spectra in Fig. 2, prime absorption peak appears to be red shifted with decreasing the concentration of cardamom extract. Besides the prime peak, some small peaks also appear around 375 nm along with the main peaks at 536 and 565 nm. In order to understand these anomalies, intensive TEM analysis of all the three samples has been carried out. Figure 3 depicts the typical transmission electron micrograph of gold nanoparticles synthesized by using black cardamom extract as a reducing agent in different ratios to HAuCl4. Figure 3a represents the particles resulting from the reduction of HAuCl4 with black cardamom extract in a ratio of 1:1. It has been shown that the particles are lying in reasonably good dispersion. Figure 3b represents a magnified image of these gold nanoparticles at the scale bar of 50 nm, which clearly reveal that the particles are nearly spherical in shape. Sizes of the particles have also been calculated and found to be in the range of 15–20 nm. However, few anisotropic nanoparticles have also been observed but their number in one snap shot are nearly negligible (<2 %). This analysis provides a stand to conclude that the particles, synthesized with HAuCl4 and black cardamom extract in the ratio of 1:1, have found to be nearly monodisperse in nature and lying in the size range of 15–20 nm. Figure 3c, d also reveals the formation of gold nanoparticles in the case when HAuCl4 and black cardamom extract have been mixed in the ratio of 1:0.5. Two different types of particles are clearly visible in these representative micrographs. One is nearly circular or hexagonal with an average particles size of 20–30 nm and other having some equilateral triangle shapes in small numbers with an average edge length of 70–100 nm.Fig. 3


One-Step Green Synthesis of Gold Nanoparticles Using Black Cardamom and Effect of pH on Its Synthesis.

Singh AK, Srivastava ON - Nanoscale Res Lett (2015)

a–f Transmission electron micrograph of synthesized gold nanoparticles
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4559564&req=5

Fig3: a–f Transmission electron micrograph of synthesized gold nanoparticles
Mentions: After a careful investigation of spectra in Fig. 2, prime absorption peak appears to be red shifted with decreasing the concentration of cardamom extract. Besides the prime peak, some small peaks also appear around 375 nm along with the main peaks at 536 and 565 nm. In order to understand these anomalies, intensive TEM analysis of all the three samples has been carried out. Figure 3 depicts the typical transmission electron micrograph of gold nanoparticles synthesized by using black cardamom extract as a reducing agent in different ratios to HAuCl4. Figure 3a represents the particles resulting from the reduction of HAuCl4 with black cardamom extract in a ratio of 1:1. It has been shown that the particles are lying in reasonably good dispersion. Figure 3b represents a magnified image of these gold nanoparticles at the scale bar of 50 nm, which clearly reveal that the particles are nearly spherical in shape. Sizes of the particles have also been calculated and found to be in the range of 15–20 nm. However, few anisotropic nanoparticles have also been observed but their number in one snap shot are nearly negligible (<2 %). This analysis provides a stand to conclude that the particles, synthesized with HAuCl4 and black cardamom extract in the ratio of 1:1, have found to be nearly monodisperse in nature and lying in the size range of 15–20 nm. Figure 3c, d also reveals the formation of gold nanoparticles in the case when HAuCl4 and black cardamom extract have been mixed in the ratio of 1:0.5. Two different types of particles are clearly visible in these representative micrographs. One is nearly circular or hexagonal with an average particles size of 20–30 nm and other having some equilateral triangle shapes in small numbers with an average edge length of 70–100 nm.Fig. 3

Bottom Line: The black cardamom extract is used as a reducing agent for HAuCl4.3H2O.Based on Fourier transform infrared spectroscopy (FTIR) studies, a tentative mechanism of reduction of Au nanoparticles has also been proposed which includes oxidation of 1,8-cineole to 2-oxo-1,8-cineole.Further, a comprehensive study to investigate the effect of pH on the synthesis of Au nanoparticles has been carried out.

View Article: PubMed Central - PubMed

Affiliation: DST Unit on Nanoscience and Technology, Department of Physics, Banaras Hindu University, Varanasi, 221005, India, ashwanikumarsingh143@gmail.com.

ABSTRACT
In the present article, an effective, one-step, and environmentally benign protocol for the synthesis of gold nanoparticles has been discussed. The black cardamom extract is used as a reducing agent for HAuCl4.3H2O. In order to synthesize gold nanoparticles, an aqueous solution of HAuCl4.3H2O was mixed with an optimized concentration of black cardamom extract where 1,8-cineole is the dominant component. Choosing black cardamom extract as a reducing agent can be justified under the light of the fact that it has a very fast reducing ability. Gold nanoparticles with different shapes and sizes were synthesized by varying the ratio of AuCl4 ions to black cardamom extract. Kinetics of reactions has been evaluated through monitoring of surface plasmon behavior of gold nanoparticles as a function of time. Based on Fourier transform infrared spectroscopy (FTIR) studies, a tentative mechanism of reduction of Au nanoparticles has also been proposed which includes oxidation of 1,8-cineole to 2-oxo-1,8-cineole. Further, a comprehensive study to investigate the effect of pH on the synthesis of Au nanoparticles has been carried out.

No MeSH data available.


Related in: MedlinePlus