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ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
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Two dimensional heterostructure have been widely investigated for various applications in electrochemistry such as water splitting and battery storage. These heterostructures are mainly formed due to vander waals interaction, covalent cross-linking and electrostatic interactions. Herein, we have prepared nanocomposite of positively charged poly (diallyldimethylammonium chloride) (PDDA, shown as P)-functionalized reduced graphene oxide (RGO) and borocarbonitride (BC 6 N, shown as BCN for simplicity) sheets with layers of negatively charged MoS 2 and MoSe 2 by electrostatic interaction in solution phase. The nanocomposites exhibit superior photocatalytic hydrogen evolution reaction (HER) activity compared to the individual components, and the value increases with the MoS 2 /MoSe 2 content. The highest photocatalytic HER activity obtained is 11230 μmol h –1 g –1 in the nanocomposite P.RGO-MoS 2 , with a P.RGO-MoS 2 ratio of 1:5. The P.RGO-MoSe 2 (1:5) and P.BCN-MoS 2 (1:5) nanocomposites exhibit somewhat lower activities of 9540 and 8593 μmol h –1 g –1 , respectively. Prompted by literature reports that carbon-rich BCNs are efficient HER electrocatalysts, we have examined the electrocatalytic HER activity of P.BCN-MoS 2 (1:1, 1:5, and 1:7) nanocomposites. The electrocatalytic HER activity of P.BCN-MoS 2 (1:5) is found to be extraordinary, with an onset potential of −50 mV (vs RHE), comparable to that of platinum. References: - Geim, A. K. & Grigorieva, I. V. Van der Waals heterostructures. Nature 2013 499:7459 499 , 419–425 (2013). Pramoda, K., Gupta, U., Ahmad, I., Kumar, R. & Rao, C. N. R. Assemblies of covalently cross-linked nanosheets of MoS2 and of MoS2–RGO: synthesis and novel properties. J Mater Chem A Mater 4 , 8989–8994 (2016). Pramoda, K., Servottam, S., Kaur, M. & Rao, C. N. R. Layered Nanocomposites of Polymer-Functionalized Reduced Graphene Oxide and Borocarbonitride with MoS2 and MoSe2 and Their Hydrogen Evolution Reaction Activity. ACS Appl Nano Mater 3 , 1792–1799 (2020). Figure 1
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
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Pyrolysis of metallocenes such as ferrocene, cobaltocene and nickelocene, is shown to yield carbon nanotubes and metal-filled onion-like structures. Pyrolysis of benzene in the presence of a metallocene gives high yields of nanotubes, the wall thickness of the nanotubes depending on the metallocene content. Pyrolysis of benzene in the absence of any metal however gives monodispersed nanospheres of carbon rather than nanotubes.
29Si chemical shifts in a wide variety of silicates in crystalline, glassy and gel states have been related to a parameter, P, which takes into account the electronegativity and the structural description of the silicate units as well as the ionic potential of the modifier cation. The relation, δ(ppm)=28.4 [1−exp(−P)]−110.5, besides having predictive value, satisfactorily accounts for all the available chemical-shifts data on silicates and shows the right kind of limiting behaviour, with δ approaching the Q0 value at large P.
The discovery of giant magnetoresistance (GMR) in rare earth manganates of the general formula Ln 1–x A x MnO 3 (Lnrare earth, A=divalent cation) has aroused much interest not only because of its technological implications, but also due to the fascinating features and mechanism of the phenomemon in these oxides. GMR is observed in these manganates when they become ferromagnetic and transform from an insulating state to a metallic state close to the Curie temperature. The essential features of magnetoresistance in the manganates can be understood on the basis of the double‐exchange mechanism, but this is too simplistic to account for all the observed data. The most curious property of the manganates relates to the high resistivity exhibited in the so‐called metallic state. Charge ordering competes with the double‐exchange interaction responsible for ferromagnetism and GMR in these materials. The charge‐ordered (charge‐crystal) insulating state in the rare earth manganates can be melted into a metallic and ferromagnetic charge‐liquid state by applying a magnetic field, thus providing a unique case of charge and spin separation in solids. The observation of GMR in Tl 2 Mn 2 O 7 shows that there can be causes other than double‐exchange for the phenomenon.
By heating mixtures of H3BO3, TiCl4, and NbCl5 with urea in 1:6 molar ratios in the 900–1000°C range, nanoparticles of BN, TiN, and NbN have been obtained, respectively. The nanoparticles are crystalline and have been characterized by electron microscopy and other techniques. By carrying out the urea reaction over Au islands deposited on Si substrates, nanowires of TiN could be obtained.
The structure of two new phases in the bismuth manganite system are reported. The phases were determined by electron diffraction studies of two oxygen-deficient bulk samples. The first phase, a minority component of bulk BiMnO2.94 forms a n = 2 Ruddlesden-Popper phase with space group Cmc21. The second phase, from bulk BiMnO2.99, is an orthorhombic structure with space groupPmn21 and a unit cell approximately equal to times the parent perovskite cell. Importantly both phases are non-centrosymmetric and offer further potential for multiferroic studies.
Ever since the discovery of carbon nanotubes, several strategies have been developed for the synthesis of multi-walled carbon nanotubes (MWNTs) as well as single-walled carbon nanotubes (SWNTs). We examine novel methods such as the precursor route and nebulized spray pyrolysis for the synthesis of MWNTs as well as junction nanotubes. Nanotubes of inorganic layered materials obtained by various ingenious methods are discussed. Nanowires of inorganic materials are synthesized not only by high temperature methods such as the carbon-assisted route, but also by soft chemical routes. We describe some of the soft chemical routes for the synthesis of inorganic nanotubes and nanowires. Some of the properties and applications of the nanotubes and nanowires are briefly described.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
