Rajinder Singh

Facile hydrothermal synthesis of nanocomposites of nitrogen doped graphene with metal molybdates (NG-MMoO4) (M=Mn, Co, and Ni) for enhanced photodegradation of methylene blue

A facile one-pot hydrothermal synthesis of nanocomposites of nitrogen doped graphene with MnMoO4/CoMoO4/NiMoO4 is reported. The morphological and structural characteristics of prepared NG-MMoO4 nanocomposites have been characterized by Powder X-ray diffraction, Fourier transform vibrational spectroscopy, Scanning electron microscopy, Transmission electron microscopy and Thermal analysis. The molybdates are well-anchored and uniformly distributed on the surface of nitrogen doped graphene sheets. The nanocomposites exhibit excellent photocatalytic activity as demonstrated by photodegradation of methylene blue under Ultraviolet–Visible irradiation by using NG-MnMoO4 as catalyst.

Facies Associations and Discontinuous Surfaces in the Syringothyris Limestone Formation of Tethyan Margin of Gondwana, Kashmir

Abstract The early Carboniferous sedimentation of the Tethyan Margin of Gondwana in the Kashmir Himalaya represents alternating siliciclastic - carbonate succession consisting of distinct stratigraphic sequences which are bounded by discontinuities. The discontinuities in the sedimentation are related to environmental changes in the form of subaerial exposure, subaqueous erosion, subaqueous omission or changes in texture and facies. These distinct surface zones or time significant boundaries can be correlated across the depositional platform. Low stand, high stand and transgressive sedimentation units in the lower and middle parts of early Carboniferous Syringothyris Limestone Formation in Banihal area have been recognised. This is explained by superposition of high frequency and low amplitude sea level fluctuations on a large-scale trend under greenhouse conditions during the early Carboniferous period. The facies associations present in the early Carboniferous succession of the Himalaya broadly represent intertidal (peritidal), shallow subtidal, deeper subtidal, off-shore-slope and deeper environments. Discontinuities that are interpreted as progradational, retrogradational and aggradational phases of sedimentation bound these facies associations. This formation represents continental margin depositional setting which is authenticated by deposition of siliciclastic sediments. This marginal depositional setting is greatly affected by numerous dynamic processes including tectonic and other active sea as well as continental processes. The records of all those processes in this formation reflect the eustatic changes in sea level. These periodic eustatic changes have generated the various discontinuities, stratigraphic sequences or systems tracts. Overall it appears that interplay of many processes such as sediment supply, thermal and tectonic activity, eustatic and climatic changes in the Kashmir Tethyan depositional basin generated these distinct depositional sequences during the early Carboniferous period.

Synthesis and characterization of K2NiF4-type phases Ln0.5Sr1.5Mn0.5Fe0.5O4 (Ln = La, Nd, Gd, and Dy)

A systematic investigation of layered perovskite oxides with general formula Ln0.5Sr1.5Mn0.5Fe0.5O4 (Ln = La, Nd, Gd, and Dy) has been undertaken mainly to understand their structural, magnetic, as well as electrical behavior. The materials were prepared by the ceramic method. X-ray data have been analyzed by using program Checkcell and the variations of various parameters are explained. It has been concluded that not only A-site cation radius, , but also the size variance factor (σ2) influence electrical and magnetic properties. A systematic study of electrical resistivity of all the four materials was undertaken as a function of temperature to understand the conduction mechanism. On analyzing the electrical resistivity data, it has been concluded that variable range hopping model is found to fit well. The magnetic studies suggest that the phases are antiferromagnetic and this behavior could arise from Mn4+–O–Mn4+, and Fe3+–O–Fe3+ superexchange interaction.

Synthesis, crystal structure, and porosity of 1D coordination polymer of neodymium(III) with isonicotinic acid and dimeric complex of neodymium(III) with nicotinic acid

A 1D coordination polymer [Nd3(INA)9(H2O)6]n (I) and a dimeric complex with mononuclear asymmetric unit [Nd(NA)3(H2O)2] (II) (HINA = isonicotinic acid and HNA = nicotinic acid) were synthesized. The compounds were characterized by elemental analyses, infrared spectroscopy and single crystal X-ray diffraction studies (CIF file CCDC nos. 938976 (I) and 939061 (II). X-ray crystal structure analysis reveals that both compounds exhibit rich structural chemistry. Compounds I and II belong to the monoclinic system with space group P21/c. Thermogravimetric analysis has been performed to investigate their thermal stability. The coordination polymer I has meso-porous structure with average diameter of pores (∼4 nm) and BET surface area 13.62 m2/g.

Erratum to: Study of Structural, Electrical, and Magnetic Properties of Layered Perovskite Oxides LnSr2TiFeO7 (Ln = Nd, Gd)

We report here the synthesis and results of electrical resistivity and magnetic susceptibility measurements in the low temperature range of the rare-earth-doped bilayered system LnSr2TiFeO7 (Ln = Nd, Gd). Both phases crystallize with a tetragonal unit cell in space group I4/mmm. The phases exhibit insulating behavior, and the electrical transport mechanism agrees with the Mott variable-range hopping model. The decrease in electrical resistivity with decreasing ionic size of the rare-earth ion could be attributed to enhancement of the three-dimensional (3D) character along the c-axis because of the proximity of the (Ti/Fe)O2 and (Ln,Sr)O layers along the c-axis. The magnetic studies suggest that the phases are antiferromagnetic and the antiferromagnetic behavior could be due to the Fe3+-O–Fe3+ exchange interaction.

Hydrothermal synthesis of magnetic Fe 3 O 4 –nitrogen-doped graphene hybrid composite and its application as photocatalyst in degradation of methyl orange and methylene blue dyes in presence of copper (II) ions

Nanocomposite of Fe3O4–nitrogen-doped graphene (Fe3O4–NG) was synthesized by single step hydrothermal method. The as-synthesized composite was characterised by various techniques such as powder X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometry and thermal analysis (TGA). The catalytic role of synthesized nanocomposite in visible light induced photodegradation of methyl orange (MO; acidic dye) and methylene blue (MB; basic dye) was explored. The role of Cu(II) ions on the photodegradation of the organic dyes was also monitored. Cu(II) ions enhance the photocatalytic activity of nanocomposite by capturing photoelectron, thereby quenching the recombination process of electron–hole pair in photocatalyst.

Solvothermal synthesis of ZnO-nitrogen doped graphene composite and its application as catalyst for photodegradation of organic dye methylene blue

A facile one step solvothermal method is designed for the synthesis of visible light-sensitive ZnO-nitrogen doped graphene (ZNG) nano photocatalysts using ethylene glycol as a solvent as well as an agent to prevent aggregation of graphene layers. The deposition of ZnO nanoparticles onto the NG layers was confirmed by high resolution transmission electron microscope (HR-TEM), scanning electron microscope (SEM), powder X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). UV-Vis spectroscopy (UV-Vis) was used to study the enhanced photocatalytic activity, which shows the red-shift of the band-edge as compared to ZnO nano particles. The enhancement in photocatalytic activity is possibly due to the synergistic effect of improved adsorptivity of dyes, enhanced visible light absorption and effective charge separation.

Surfactant-assisted sacrificial template-mediated synthesis, characterization and photoluminescent properties of \(\hbox {LaPO}_{4}:\hbox {Eu}^{3+}\) phosphor

In this paper, we report a surfactant-assisted self-sacrificing route for synthesis of Eu3+\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}

Rietveld Refinements of K2NiF4-Type Phases Ln0.5Sr1.5Mn0.5Fe0.5O4 (Ln = La, Nd, Gd, and Dy)

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