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Rajiv Prakash - One of the best experts on this subject based on the ideXlab platform.
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Photochemically mediated synthesis of a gold colloid by Dithizone and its application in the amperometric sensing of thiocyanate
RSC Advances, 2015Co-Authors: Sandeep Gupta, Rajiv PrakashAbstract:This paper highlights a one-step facile approach for the photochemically assisted synthesis of stable gold colloids (Au) using Dithizone (DTZ) without any extra controls, viz. surfactant, seeds, pH etc. Although Dithizone chemistry has been documented extensively in scientific reports, it is amazing to note that there are scarcely any reports published so far on the photochemically mediated formation of gold nanostructures using Dithizone. The as-prepared electroactive hybrid nanomaterial was extensively investigated using various characterization techniques, including UV-visible spectroscopy, FT-IR, cyclic voltammetry, amperometry, TEM, FESEM and XPS. The formation of the gold nanostructure over time by exposure to light using Dithizone was ascertained, with the results complemented by time dependent UV-visible as well as TEM studies. A conceivable reaction mechanism for the formation of the gold nanostructure has also been proposed. The use of Dithizone as a reductant as well as a stabilizer offers great advantages in terms of simplicity during synthesis, i.e., a one-pot synthesis, use of aqueous/organic media, no external reducing agent and a very limited post-synthesis work-up. Furthermore, an electroactive advanced hybrid nanomaterial derived from nanoscale gold protected with Dithizone (DTZ) and its oxidation product (DTZH) has been utilized for the amperometric sensing of hazardous thiocyanate. The modified electrode with the hybrid material efficiently electrocatalyzes the oxidation of thiocyanate at a potential of 0.55 V vs. AgCl/Ag and shows a linear response toward thiocyanate sensing with a sensitivity of 0.016 μA nM−1 and a limit of detection of 23.348 nM at a S/N (signal-to-noise ratio) of 3. The electrochemistry behind the sensing of thiocyanate is possibly due to electrostatic interactions (DTZH⋯SCNn−⋯Aum+⋯SCNn−⋯DTZH complexation) and the conducting gold nanoparticles facilitating the efficient collection and transfer of electrons to the modified electrode.
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Photochemically assisted formation of silver nanoparticles by Dithizone, and its application in amperometric sensing of cefotaxime
J. Mater. Chem. C, 2014Co-Authors: Sandeep Gupta, Rajiv PrakashAbstract:This paper reports a convenient approach for one-pot, facile, photochemically assisted synthesis of stable silver colloids (Ag) by using Dithizone (DTZ)/its oxidation products (DTZH) as a reductant/particle stabilizer without any extra control such as surfactant or pH. Although Dithizone chemistry has been studied extensively, it is surprising to note that there are hardly any studies published thus far on photochemically assisted formation of metallic nanomaterials using Dithizone. We revisit the chemistry of Dithizone based upon previous reports and synthesize silver nanoparticles (Ag–DTZH) photochemically using Dithizone. The prepared hybrid nanomaterial (Ag–DTZH) has been characterized by UV-visible spectroscopy, infrared spectroscopy, cyclic voltammetry, transmission electron microscopy, field-emission scanning electron microscopy and X-ray photoelectron spectroscopy techniques. Nanosilver formation by exposure to light is studied for various time intervals using UV-visible spectroscopy as well as TEM. This hybrid material derived from nanoscale silver protected with Dithizone and its oxidation product has been further utilized for electro-sensing of cefotaxime (CFX), which is a third-generation cephalosporin antibiotic drug. Moreover, a possible reaction mechanism for the formation of silver nanostructures has been proposed. Modified electrodes with hybrid nanomaterial (Ag–DTZH) efficiently electro-catalyzes the oxidation of cefotaxime at the potential of 0.789 V vs. AgCl/Ag and shows a linear response toward cefotaxime sensing with 0.244 μA μM−1 sensitivity and a 15.32 nM limit of detection at signal-to-noise ratio (S/N): 3. The electrochemistry behind this sensing of cefotaxime is probably due to high connectivity throughout the silver nanostructure (Ag–DTZH) capped with Dithizone and its oxidation product over the modified electrode. It exhibits high-electron transfer kinetics via the interaction of Ag–DTZH with –NH2 and –COOH groups present in CFX. The present finding will open new avenues in the field of electro-sensing of analytes with this hybrid material-modified electrode.
Sandeep Gupta - One of the best experts on this subject based on the ideXlab platform.
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Photochemically mediated synthesis of a gold colloid by Dithizone and its application in the amperometric sensing of thiocyanate
RSC Advances, 2015Co-Authors: Sandeep Gupta, Rajiv PrakashAbstract:This paper highlights a one-step facile approach for the photochemically assisted synthesis of stable gold colloids (Au) using Dithizone (DTZ) without any extra controls, viz. surfactant, seeds, pH etc. Although Dithizone chemistry has been documented extensively in scientific reports, it is amazing to note that there are scarcely any reports published so far on the photochemically mediated formation of gold nanostructures using Dithizone. The as-prepared electroactive hybrid nanomaterial was extensively investigated using various characterization techniques, including UV-visible spectroscopy, FT-IR, cyclic voltammetry, amperometry, TEM, FESEM and XPS. The formation of the gold nanostructure over time by exposure to light using Dithizone was ascertained, with the results complemented by time dependent UV-visible as well as TEM studies. A conceivable reaction mechanism for the formation of the gold nanostructure has also been proposed. The use of Dithizone as a reductant as well as a stabilizer offers great advantages in terms of simplicity during synthesis, i.e., a one-pot synthesis, use of aqueous/organic media, no external reducing agent and a very limited post-synthesis work-up. Furthermore, an electroactive advanced hybrid nanomaterial derived from nanoscale gold protected with Dithizone (DTZ) and its oxidation product (DTZH) has been utilized for the amperometric sensing of hazardous thiocyanate. The modified electrode with the hybrid material efficiently electrocatalyzes the oxidation of thiocyanate at a potential of 0.55 V vs. AgCl/Ag and shows a linear response toward thiocyanate sensing with a sensitivity of 0.016 μA nM−1 and a limit of detection of 23.348 nM at a S/N (signal-to-noise ratio) of 3. The electrochemistry behind the sensing of thiocyanate is possibly due to electrostatic interactions (DTZH⋯SCNn−⋯Aum+⋯SCNn−⋯DTZH complexation) and the conducting gold nanoparticles facilitating the efficient collection and transfer of electrons to the modified electrode.
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Photochemically assisted formation of silver nanoparticles by Dithizone, and its application in amperometric sensing of cefotaxime
J. Mater. Chem. C, 2014Co-Authors: Sandeep Gupta, Rajiv PrakashAbstract:This paper reports a convenient approach for one-pot, facile, photochemically assisted synthesis of stable silver colloids (Ag) by using Dithizone (DTZ)/its oxidation products (DTZH) as a reductant/particle stabilizer without any extra control such as surfactant or pH. Although Dithizone chemistry has been studied extensively, it is surprising to note that there are hardly any studies published thus far on photochemically assisted formation of metallic nanomaterials using Dithizone. We revisit the chemistry of Dithizone based upon previous reports and synthesize silver nanoparticles (Ag–DTZH) photochemically using Dithizone. The prepared hybrid nanomaterial (Ag–DTZH) has been characterized by UV-visible spectroscopy, infrared spectroscopy, cyclic voltammetry, transmission electron microscopy, field-emission scanning electron microscopy and X-ray photoelectron spectroscopy techniques. Nanosilver formation by exposure to light is studied for various time intervals using UV-visible spectroscopy as well as TEM. This hybrid material derived from nanoscale silver protected with Dithizone and its oxidation product has been further utilized for electro-sensing of cefotaxime (CFX), which is a third-generation cephalosporin antibiotic drug. Moreover, a possible reaction mechanism for the formation of silver nanostructures has been proposed. Modified electrodes with hybrid nanomaterial (Ag–DTZH) efficiently electro-catalyzes the oxidation of cefotaxime at the potential of 0.789 V vs. AgCl/Ag and shows a linear response toward cefotaxime sensing with 0.244 μA μM−1 sensitivity and a 15.32 nM limit of detection at signal-to-noise ratio (S/N): 3. The electrochemistry behind this sensing of cefotaxime is probably due to high connectivity throughout the silver nanostructure (Ag–DTZH) capped with Dithizone and its oxidation product over the modified electrode. It exhibits high-electron transfer kinetics via the interaction of Ag–DTZH with –NH2 and –COOH groups present in CFX. The present finding will open new avenues in the field of electro-sensing of analytes with this hybrid material-modified electrode.
Mahmut Özacar - One of the best experts on this subject based on the ideXlab platform.
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The effects of metal doped TiO2 and Dithizone-metal complexes on DSSCs performance
Solar Energy, 2018Co-Authors: Burak Ünlü, Soner Çakar, Mahmut ÖzacarAbstract:Abstract Different metal (Fe, Ni, Co or Zn) doped TiO2 nanoparticles and Dithizone-metal (Fe, Ni, Co or Zn)-gallic acid complexes were prepared and used in dye sensitized solar cells (DSSCs). The TiO2 and metal doped TiO2 nanoparticles were synthesized by microwave assisted hydrothermal method. Synthesized TiO2 nanoparticles were characterized with SEM, EDS, XRD and DRS. Prepared Dithizone-metal-gallic acid complexes were characterized via UV–Vis and FTIR techniques. Photoanode of DSSC was prepared with TiO2 or metal doped TiO2 coating on FTO-glass using spin coater. The Dithizone and Dithizone-metal-gallic acid complexes were adsorbed on bare TiO2, and Dithizone or N719 were adsorbed on metal doped TiO2. Then, sandwich type DSSCs were prepared and electrochemical characterization of DSSCs was made. When the N719 and Dithizone sensitized metal doped TiO2 nanoparticles were compared with undoped TiO2, Fe doped TiO2 gave lower efficiency, Ni, Co and Zn doped TiO2 gave higher efficiency than that of undoped TiO2. Co doped samples showed the highest efficiencies with both N719 and Dithizone. Co doped TiO2 which was sensitized with Dithizone gave nearly three times more conversion efficiency than undoped TiO2. These results show that doping procedure can enhance binding dyes to semi conductor surface. In summary, various metals show different characteristics when doped to TiO2 nanoparticles.
Rawiwan Maniratanachote - One of the best experts on this subject based on the ideXlab platform.
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Interaction evaluation of silver and Dithizone complexes using DFT calculations and NMR analysis.
Spectrochimica acta. Part A Molecular and biomolecular spectroscopy, 2015Co-Authors: Nootcharin Wasukan, Sujittra Srisung, Mayuso Kuno, Kornphimol Kulthong, Rawiwan ManiratanachoteAbstract:Silver has distinct antibacterial properties and has been used as a component of commercial products with many applications. An increasing number of commercial products cause risks of silver effects for human and environment such as the symptoms of Argyria and the release of silver to the environment. Therefore, the detection of silver in the aquatic environment is important. The colorimetric chemosensor is designed by the basic of ligand interactions with metal ion, leading to the change of signals for the naked-eyes which is very useful method to this application. Dithizone ligand is considered as one of the effective chelating reagents for metal ions due to its high selectivity and sensitivity of a photochromic reaction for silver as well as the linear backbone of Dithizone affords the rotation of various isomeric forms. The present study is focused on the conformation and interaction of Dithizone with silver using density functional theory (DFT). The interaction parameters were determined in term of binding energy of complexes and the geometry optimization, frequency of the structures and calculation of binding energies using density functional approaches B3LYP and the 6-31G(d,p) basis set. Moreover, the interaction of silver-Dithizone complexes was supported by UV-Vis spectroscopy, FT-IR spectrum that were simulated by using B3LYP/6-31G(d,p) and (1)H NMR spectra calculation using B3LYP/6-311+G(2d,p) method compared with the experimental data. The results showed the ion exchange interaction between hydrogen of Dithizone and silver atom with minimized binding energies of silver-Dithizone interaction. Therefore, the results can be the useful information for determination of complex interaction using the analysis of computer simulations.
Burak Ünlü - One of the best experts on this subject based on the ideXlab platform.
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The effects of metal doped TiO2 and Dithizone-metal complexes on DSSCs performance
Solar Energy, 2018Co-Authors: Burak Ünlü, Soner Çakar, Mahmut ÖzacarAbstract:Abstract Different metal (Fe, Ni, Co or Zn) doped TiO2 nanoparticles and Dithizone-metal (Fe, Ni, Co or Zn)-gallic acid complexes were prepared and used in dye sensitized solar cells (DSSCs). The TiO2 and metal doped TiO2 nanoparticles were synthesized by microwave assisted hydrothermal method. Synthesized TiO2 nanoparticles were characterized with SEM, EDS, XRD and DRS. Prepared Dithizone-metal-gallic acid complexes were characterized via UV–Vis and FTIR techniques. Photoanode of DSSC was prepared with TiO2 or metal doped TiO2 coating on FTO-glass using spin coater. The Dithizone and Dithizone-metal-gallic acid complexes were adsorbed on bare TiO2, and Dithizone or N719 were adsorbed on metal doped TiO2. Then, sandwich type DSSCs were prepared and electrochemical characterization of DSSCs was made. When the N719 and Dithizone sensitized metal doped TiO2 nanoparticles were compared with undoped TiO2, Fe doped TiO2 gave lower efficiency, Ni, Co and Zn doped TiO2 gave higher efficiency than that of undoped TiO2. Co doped samples showed the highest efficiencies with both N719 and Dithizone. Co doped TiO2 which was sensitized with Dithizone gave nearly three times more conversion efficiency than undoped TiO2. These results show that doping procedure can enhance binding dyes to semi conductor surface. In summary, various metals show different characteristics when doped to TiO2 nanoparticles.