10 research outputs found
Enhanced visible light photocatalytic performance of SnO2 nanoparticle co-doped with (Co, Nb) for organic dye degradation
No full textFunding Information: The authors: S. Jayapandi acknowledges UGC for providing Non-NET fellowship. S. Premkumar acknowledges SERB for NPDF fellowship (PDF/2016/001726). D. Lakshmi acknowledges CSIR-RA (09/472(0183)/219-EMR-I/28.03.2019) for the financial aid. Publisher Copyright: © 2020, Springer Science+Business Media, LLC, part of Springer Nature.Fast electron–hole recombination rate, lower free radical generation, unsuitable valence band maximum (VBM) and conduction band minimum (CBM) position of SnO2 nanoparticle are the shortfalls in achieving a superior photocatalytic performance of organic dye degradation under sunlight irradiation. To rise above these margins, for the first time, the co-doping approach was attempted by a simple co-precipitation technique in which both cobalt (Co) and niobium (Nb) were doped in SnO2 nanoparticle. In this regard, pure, mono-doped 5 M Co, 5 M Nb and different concentrations of (Co, Nb) co-doped SnO2 nanoparticles were prepared and characterized through XRD, UV–Vis, PL, XPS, SEM, and cyclic voltammetry analyses. Moreover, the influence of crystalline nature, bond order, bandgap, electron–hole recombination rate, and VBM and CBM potential to the efficient photocatalytic activity have been discussed. The observed UV–Vis, PL, and cyclic voltammetry measurements revealed that the (Co, Nb) co-doped SnO2 nanoparticles have suitable CBM to meet better reduction capacity, lower electron–hole recombination rates, and higher stability than pure and mono-doped system. XPS analysis confirmed the presence of both Co and Nb in the SnO2 matrix and O1s spectrum revealed the presence of hydroxyl radical on its surface. Also, the terephthalic (TA) acid test showed that, at higher concentration of cobalt co-doped SnO2 nanoparticles, it generated maximum hydroxyl (OH·) radicals than that of others. Consequently, those nanoparticles exhibited 99% efficiency of methylene blue (MB) dye degradation at 30 min under direct sunlight atmosphere. For better photocatalytic outsight, the photodegradation mechanism was also proposed
Augmented photocatalytic and electrochemical activities of Ag tailored LaCoO3 perovskite semiconductor
No full textInorganic perovskite materials have drawn significant interest in photocatalytic application owing to their excellent photo absorbing nature. In this regard, we have synthesized pristine and silver (Ag) modified lanthanum cobaltite (LaCoO3) perovskite by hydrothermal method and characterized by multitechnique approaches. The structural, absorption and emission studies reveal that addition of Ag influences the crystallite size, absorption co-efficient and electron hole recombination rate of LaCoO3. Morphological analysis shows that tetragonal morphology of the pure LaCoO3 is changed to square shape morphology on addition of Ag, which reveals the dispersion of Ag into LaCoO3. Electrochemical analysis demonstrates the possible electrochemical activity of the materials and confirms that Ag provides higher charge transfer kinetics and stability to LaCoO3. In addition, Ag-LaCoO3 degrades methylene blue (MB) in higher rate (99% in 10 min) compared to LaCoO3 (75% in 10 min). Mechanism behinds the photocatalytic activity has been discussed. Hence, the present investigation explores Ag modified LaCoO3 as a newpotential candidate for the application in photocatalytic activity under sunlight irradiation. (C) 2018 Elsevier B.V. All rights reserved
Influence of pH in La-doped SnO2 nanoparticles towards sensor applications
No full textThe present investigation has been carried out to optimize the pH level of lanthanum (La)-doped tin dioxide (SnO2) nanoparticles towards the potential application in gas sensor. The La-doped SnO2 nanoparticles were synthesized by sol-gel method in different pH values varying from acidic to base nature. The synthesized nanoparticles were characterized by X-ray diffraction (XRD), ultraviolet (UV), photoluminescence (PL), and scanning electron microscopy (SEM) techniques. The XRD, UV, and PL analyses show the pH influences on the crystallite size of La-doped SnO2 nanoparticles. The SEM images show the formation of porous structure at pH 11. Also, the electrical conductivity of 1 mol% La-doped SnO2 at pH 3 and pH 11 were measured by impedance analyzer. In addition, we have fabricated and demonstrated device performance of synthesized La-doped SnO2 nanoparticles for gas-sensing application. Real-time current response and long-time response to the gas sensing were also studied for the fabricated device
Enhanced visible light photocatalytic performance of SnO2 nanoparticle co-doped with (Co, Nb) for organic dye degradation
No full textPublisher Copyright: © 2020, Springer Science+Business Media, LLC, part of Springer Nature.Fast electron–hole recombination rate, lower free radical generation, unsuitable valence band maximum (VBM) and conduction band minimum (CBM) position of SnO2 nanoparticle are the shortfalls in achieving a superior photocatalytic performance of organic dye degradation under sunlight irradiation. To rise above these margins, for the first time, the co-doping approach was attempted by a simple co-precipitation technique in which both cobalt (Co) and niobium (Nb) were doped in SnO2 nanoparticle. In this regard, pure, mono-doped 5 M Co, 5 M Nb and different concentrations of (Co, Nb) co-doped SnO2 nanoparticles were prepared and characterized through XRD, UV–Vis, PL, XPS, SEM, and cyclic voltammetry analyses. Moreover, the influence of crystalline nature, bond order, bandgap, electron–hole recombination rate, and VBM and CBM potential to the efficient photocatalytic activity have been discussed. The observed UV–Vis, PL, and cyclic voltammetry measurements revealed that the (Co, Nb) co-doped SnO2 nanoparticles have suitable CBM to meet better reduction capacity, lower electron–hole recombination rates, and higher stability than pure and mono-doped system. XPS analysis confirmed the presence of both Co and Nb in the SnO2 matrix and O1s spectrum revealed the presence of hydroxyl radical on its surface. Also, the terephthalic (TA) acid test showed that, at higher concentration of cobalt co-doped SnO2 nanoparticles, it generated maximum hydroxyl (OH·) radicals than that of others. Consequently, those nanoparticles exhibited 99% efficiency of methylene blue (MB) dye degradation at 30 min under direct sunlight atmosphere. For better photocatalytic outsight, the photodegradation mechanism was also proposed
Reinforced photocatalytic reduction of SnO2 nanoparticle by La incorporation for efficient photodegradation under visible light irradiation
No full textIn this era of technology, evolving and understanding the physicochemical properties of a novel photocatalytic material to degrade organic species in polluted water is most needed all over the globe due to environmental production. This study reports the influence of lanthanum (La) in physicochemical properties of tin (II) dioxide (SnO2) nanoparticles and its application towards methylene blue (MB) degradation under sunlight. The SnO2, 2mol% La incorporated SnO2 and 4mol% La incorporated SnO2 (4mol% La) nanoparticles were synthesized by simple co-precipitation method and characterized. X-ray diffraction patterns indicate higher angle shifts and peak broadening with respect to increase in La concentration. High-resolution transmission electron microscopic images (HR-TEM) reveal that SnO2 particle size decreases with respect to increase in La concentration. Morphological analysis shows that addition of La changes SnO2 morphology from agglomeration to segregated porous nature. Energy dispersive spectrum confirms the presence of parent and dopant elements in La incorporated SnO2 nanoparticles. UV-Visible spectrum indicates the increase in the band gap of La incorporated SnO2 due to the quantum size effect. The surface disorder, reduction in particle size and phonon confinement are identified from the Raman spectral analysis. Moreover, electrochemical analysis demonstrates the possible electrochemical activity of the materials as well as confirms that La provides higher charge transfer kinetics and stability to SnO2 nanoparticle. In addition, the calculated CBM potential confirms that La increases the redox potential of SnO2 nanoparticle, which is an ample condition to reduce O-2 as O-2(-). The fast MB degradation kinetics achieved by 4mol% La-SnO2 nanoparticle, which degrades 99% of MB within 60min under sunlight irradiation and exhibits more than 90% photodegradation efficiency up to ten recycle. A through study of possible photocatalytic mechanism for the photocatalytic degradation is discussed
Structure, dielectric, and temperature-dependent conductivity studies of the Li2FeSiO4/C nano cathode material for lithium-ion batteries
No full textSpatial and genetic epidemiology of hookworm in a rural community in Uganda.
No full textThere are remarkably few contemporary, population-based studies of intestinal nematode infection for sub-Saharan Africa. This paper presents a comprehensive epidemiological analysis of hookworm infection intensity in a rural Ugandan community. Demographic, kinship, socioeconomic and environmental data were collected for 1,803 individuals aged six months to 85 years in 341 households in a cross-sectional community survey. Hookworm infection was assessed by faecal egg count. Spatial variation in the intensity of infection was assessed using a Bayesian negative binomial spatial regression model and the proportion of variation explained by host additive genetics (heritability) and common domestic environment was estimated using genetic variance component analysis. Overall, the prevalence of hookworm was 39.3%, with the majority of infections (87.7%) of light intensity (<or=1000 eggs per gram faeces). Intensity was higher among older individuals and was associated with treatment history with anthelmintics, walking barefoot outside the home, living in a household with a mud floor and education level of the household head. Infection intensity also exhibited significant household and spatial clustering: the range of spatial correlation was estimated to be 82 m and was reduced by a half over a distance of 19 m. Heritability of hookworm egg count was 11.2%, whilst the percentage of variance explained by unidentified domestic effects was 17.8%. In conclusion, we suggest that host genetic relatedness is not a major determinant of infection intensity in this community, with exposure-related factors playing a greater role
