V. Selvam

Bio: V. Selvam is an academic researcher from Hindu College, University of Delhi. The author has contributed to research in topic(s): Electrochemical gas sensor & Graphitic carbon nitride. The author has an hindex of 4, co-authored 6 publication(s) receiving 61 citation(s).

A selective electrochemical sensor for caffeic acid and photocatalyst for metronidazole drug pollutant - A dual role by rod-like SrV 2 O 6 .

Abstract: In the present study, well-defined one-dimensional (1D) rod-like strontium vanadate (SrV2O6) was prepared by simple hydrothermal method without using any other surfactants/templates. The successful formation of rod-like SrV2O6 was confirmed by various analytical and spectroscopic techniques. Interestingly, for the first time the dual role of as-prepared rod-like SrV2O6 were employed as an electrochemical sensor for the detection of caffeic acid (CA) as well as visible light active photocatalyst for the degradation of metronidazole (MNZ) antibiotic drug. As an electrochemical sensor, the SrV2O6 modified glassy carbon electrode (GCE) demonstrated a superior electrocatalytic activity for the detection of CA by chronoamperometry and cyclic voltammetry (CVs). In addition, the electrochemical sensor exhibited a good current response for CA with excellent selectivity, wide linear response range, lower detection limit and sensitivity of 0.01–207 µM, 4 nM and 2.064 μA μM−1cm−2, respectively. On the other hand, as-synthesized rod-like SrV2O6 showed highly efficient and versatile photocatalytic performances for the degradation of MNZ, which degrades above 98% of MNZ solution under visible light irradiation within 60 min. The obtained results evidenced that the improvement of rod-like SrV2O6 might be a resourceful electrocatalyst and photocatalyst material in the probable applications of environmental and biomedical applications.

Emerging energy and environmental application of graphene and their composites: a review

Abstract: Graphene-based materials receive attention in the field of energy and environmental application. The unique physiochemical assets such as the high surface area, high thermal stability, chemical flexibility, high electron mobility and mechanical solidity make it a highly versatile material for different applications. In this critical review, the application of graphene-based material in energy and environmental remediation is discussed in detail. More specifically, the role of graphene in thought-provoking research fields, viz. solar cell, photocatalytic water splitting, photocatalytic degradation of organic pollutants and heavy metal removal, is focused. As graphene possesses very good carrier mobility, it enhances the photocatalytic performance of semiconducting materials. Very interestingly, graphene is being used in both hole transport layer and electron transport layer in solar cell. Similarly, high surface area of graphene assists in heavy metal removal by adsorption. The challenges and recent achievements in these fields are highlighted in this review.

A Novel Cerium Tungstate Nanosheets Modified Electrode for the Effective Electrochemical Detection of Carcinogenic Nitrite Ions

Abstract: In this present scenario, for the first time, we propose a facile and simple wet chemical approach for the fabrication of two-dimensional (2D) cerium tungstate (CeW2O9;CeW) nanosheets and evaluated as an electrochemical sensor for the detection of nitrite ions. The successful formation of CeW2O9 nanosheets was confirmed by various physicochemical techniques such as X-ray diffraction, Fourier transform infrared spectroscopy, Raman, Scanning electron microscope, Transmission electron microscope and Energy dispersive X-ray studies. The electrochemical properties of the CeW nanosheets were studied by using cyclic voltammograms (CV) and chronoamperometric techniques. As an electrochemical sensor, the CeW nanosheets modified glassy carbon electrode (GCE) showed superior electrocatalytic activity in the oxidation of nitrite in terms of higher anodic peak current and lower oxidation potential when compared with unmodified GCE. CeW nanosheets based electrochemical sensor has been fabricated which detect nitrite in wide linear response range, good sensitivity and very low detection limit of 0.02–986 μM, 2.85 μA μM−1 cm−2 and 8 nM, respectively. Moreover, the CeW nanosheets modified GCE exhibited excellent selectivity even in the presence of common metal ions and biologically co-interfering compounds. For the practical viability of the prepared amperometric sensor has been utilized in various water samples such as tap, lake and drinking water and the obtained recoveries are appreciable.

Photocatalytic degradation of organic contaminants by g-C3N4/EPDM nanocomposite film: Viable, efficient and facile recoverable.

Abstract: The original metal free graphitic carbon nitride/ethylene propylene diene monomer nanocomposite film (g-C3N4/EPDM NCF) was fabricated by facile solution cast method. g-C3N4/EPDM NCF with diameter (50mm) and thickness (4mm) was investigated towards the photocatalytic degradation of methylene blue (MB) and methyl orange (MO) dye solution under visible light irradiation. The as synthesized g-C3N4/EPDM NCF was exhibited high crystalline nature with the crystalline size of 21.53nm, the smooth surface nature and the particle size was observed from the TEM analysis is 20nm. Furthermore, the influence of operational parameters was carried out which demonstrated that 100mg photocatalyst and 25μM of dye concentration were obtained as an optimized condition for the best photocatalytic degradation results. As a result of scavenger experiment, it was concluded that the hydroxyl radical (OH) was actively involved in the photocatalytic degradation. The g-C3N4/EPDM NCF were recoverable from the photocatalytic reaction system and the present find findings may open up a new platform for the simple handpicked photocatalyst.

Recent Advances in Nanomaterials for Wastewater Treatment

Abstract: Developing an efficient wastewater treatment technique is one of the major necessities of the twenty-first century, owing to the scarcity of water resources. Besides, it is of paramount important to find appropriate methodologies to economically treat wastewater. Recent advances in nanotechnology have attracted the attention of many researchers for wastewater treatment. The major advantages of such nanomaterial-based systems are that they can be reused and have been found to be very effective. Though many research works have been reported in this regard, there is very limited collective information. Hence, the major objective of this work is to describe recent achievements in nanomaterial-based systems for wastewater treatment. This chapter critically reviews and lists the uses of nanomaterials in wastewater treatment. This comprises the utilization of semiconducting nanoparticles either alone or combined with ozonation, the Fenton process, or sonolysis for effective degradation/removal of organic pollutants. Furthermore, the effectiveness of nanotechnology in antimicrobial activity to produce pure water via an eco-friendly route is discussed. Similarly, the role of nanomaterials in adsorption techniques (specifically, carbon-based nanoadsorbents) to remove heavy metal contamination from industrial wastewater is also discussed in detail.

Ultrathin epitaxial graphite: 2D electron gas properties and a route toward graphene-based nanoelectronics

Abstract: We have produced ultrathin epitaxial graphite films which show remarkable 2D electron gas (2DEG) behavior. The films, composed of typically 3 graphene sheets, were grown by thermal decomposition on the (0001) surface of 6H-SiC, and characterized by surface-science techniques. The low-temperature conductance spans a range of localization regimes according to the structural state (square resistance 1.5 kOhm to 225 kOhm at 4 K, with positive magnetoconductance). Low resistance samples show characteristics of weak-localization in two dimensions, from which we estimate elastic and inelastic mean free paths. At low field, the Hall resistance is linear up to 4.5 T, which is well-explained by n-type carriers of density 10^{12} cm^{-2} per graphene sheet. The most highly-ordered sample exhibits Shubnikov - de Haas oscillations which correspond to nonlinearities observed in the Hall resistance, indicating a potential new quantum Hall system. We show that the high-mobility films can be patterned via conventional lithographic techniques, and we demonstrate modulation of the film conductance using a top-gate electrode. These key elements suggest electronic device applications based on nano-patterned epitaxial graphene (NPEG), with the potential for large-scale integration.

A novel electrochemical sensor based on silver/halloysite nanotube/molybdenum disulfide nanocomposite for efficient nitrite sensing.

Abstract: In the present study, the silver/halloysite nanotube/molybdenum disulfide (Ag/HNT/MoS2) nanocomposite was successfully synthesized. For this purpose, the lumen of HNTs was firstly modified by silver to generate Ag nanorods via chemical process and then the MoS2 layers deposited on the Ag/HNT nanocomposite by hydrothermal method. The characterization of Ag/HNT/MoS2 nanocomposite were investigated by field emission scanning electron microscopy (FE-SEM), Fourier transform infrared (FT-IR) spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectra (XPS), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) analyses. The nanocomposite modified carbon paste electrode (CPE) was applied for the electrocatalytic detection of nitrite in aqueous solutions. It was demonstrated that the treatment of HNTs with Ag and MoS2 materials enhanced the catalytic performance of modified CPE. At optimal experimental conditions, the designed sensor displayed remarkable sensing ability toward nitrite oxidation, offering a good linearity from 2 to 425 µM. The limit of detection (LOD) of the proposed strategy was estimated to be 0.7 µM based S/N = 3. The good reproducibility, acceptable stability, fast response time and anti-interference performance of the proposed assay suggests that the modified CPE has great potential working as a nitrite electrochemical sensor for environmental applications.

Recent advances in photodegradation of antibiotic residues in water

Abstract: Antibiotics are widely present in the environment due to their extensive and long-term use in modern medicine. The presence and dispersal of these compounds in the environment lead to the dissemination of antibiotic residues, thereby seriously threatening human and ecosystem health. Thus, the effective management of antibiotic residues in water and the practical applications of the management methods are long-term matters of contention among academics. Particularly, photocatalysis has attracted extensive interest as it enables the treatment of antibiotic residues in an eco-friendly manner. Considerable progress has been achieved in the implementation of photocatalytic treatment of antibiotic residues in the past few years. Therefore, this review provides a comprehensive overview of the recent developments on this important topic. This review primarily focuses on the application of photocatalysis as a promising solution for the efficient decomposition of antibiotic residues in water. Particular emphasis was laid on improvement and modification strategies, such as augmented light harvesting, improved charge separation, and strengthened interface interaction, all of which enable the design of powerful photocatalysts to enhance the photocatalytic removal of antibiotics.

Carbon dots coated with molecularly imprinted polymers: A facile bioprobe for fluorescent determination of caffeic acid.

Abstract: A new and sensitive method for fluorescent determination of caffeic acid (CA) was proposed based on silane-functionazed carbon dots coated with molecularly imprinted polymers (CDs@MIPs). CDs@MIPs were prepared by using CA as the templates on the surface of silane-functionazed carbon dots(CDs) with a sol–gel process. The as-prepared CDs@MIPs were characterized by Fourier transform infrared spectroscopy, transmission electron microscopy and fluorescence spectroscopy. The CDs@MIPs exhibited distinguished selectivity and high binding affinity to CA templates, and also showed good reusability. Under optimal conditions, the fluorescence intensity of CDs@MIPs decreased linearly with the increase of CA in the range of 0.5–200 μM. The limit of detection was 0.11 μM (3σ/K). Finally, the proposed method was successfully applied to the detection of CA in human plasma. The result indicates that the method built has promising potential for monitoring CA concentration in clinic.