Molecular Clusters in Mesoporous Materials as Precursors to Nanoparticles of a New Lacunar Ternary Compound PdxMoyP

Bimetallic clusters of composition Pd2Mo2(g5-C5H5)2(l3-CO)2(l2-CO)4 (PR3)2 (R = ethyl or phenyl) were incorporated by impregnation from solution into two different silica matrices, amorphous xerogels and ordered SBA-15, and a study of their thermal decomposition under a reducing atmosphere is reported. With both matrices, a suitable thermal treatment afforded nanoparticles of a new bimetallic phosphide. Although nanoparticles of composition PdxMoyP, isostructural with Mo3P, were formed in both matrices, they were more uniformly distributed in the SBA-15 framework and showed a narrower size distribution. The samples have been characterized by powder XRD, chemical analysis, FT-IR spectroscopy, TEM and electron tomography (3D TEM)

Advice on assistance and protection from the Scientific Advisory Board of the Organisation for the Prohibition of Chemical Weapons : Part 2. On preventing and treating health effects from acute, prolonged, and repeated nerve agent exposure, and the identification of medical countermeasures able to reduce or eliminate the longer term health effects of nerve agents

The Scientific Advisory Board (SAB) of the Organisation for the Prohibition of Chemical Weapons (OPCW) has provided advice in relation to the Chemical Weapons Convention on assistance and protection. We present the SAB’s response to a request from the OPCW Director-General in 2014 for information on the best practices for preventing and treating the health effects from acute, prolonged, and repeated organophosphorus nerve agent (NA) exposure. The report summarises pre- and post-exposure treatments, and developments in decontaminants and adsorbing materials, that at the time of the advice, were available for NAs. The updated information provided could assist medics and emergency responders unfamiliar with treatment and decontamination options related to exposure to NAs. The SAB recommended that developments in research on medical countermeasures and decontaminants for NAs should be monitored by the OPCW, and used in assistance and protection training courses and workshops organised through its capacity building programmes.Peer reviewe

advice from the scientific advisory board of the organisation for the prohibition of chemical weapons on isotopically labelled chemicals and stereoisomers in relation to the chemical weapons convention

AbstractThe Chemical Weapons Convention (CWC) is an international disarmament treaty that prohibits the development, stockpiling and use of chemical weapons. This treaty has 193 States Parties (nations for which the treaty is binding) and entered into force in 1997. The CWC contains schedules of chemicals that have been associated with chemical warfare programmes. These scheduled chemicals must be declared by the States that possess them and are subject to verification by the Organisation for the Prohibition of Chemical Weapons (OPCW, the implementing body of the CWC). Isotopically labelled and stereoisomeric variants of the scheduled chemicals have presented ambiguities for interpretation of the requirements of treaty implementation, and advice was sought from the OPCW's Scientific Advisory Board (SAB) in 2016. The SAB recommended that isotopically labelled compounds or stereoisomers related to the parent compound specified in a schedule should be interpreted as belonging to the same schedule. This advice should benefit scientists and diplomats from the CWC's State Parties to help ensure a consistent approach to their declarations of scheduled chemicals (which in turn supports both the correctness and completeness of declarations under the CWC). Herein, isotopically labelled and stereoisomeric variants of CWC-scheduled chemicals are reviewed, and the impact of the SAB advice in influencing a change to national licensing in one of the State Parties is discussed. This outcome, an update to national licensing governing compliance to an international treaty, serves as an example of the effectiveness of science diplomacy within an international disarmament treaty

innovative technologies for chemical security

AbstractAdvances across the chemical and biological (life) sciences are increasingly enabled by ideas and tools from sectors outside these disciplines, with information and communication technologies playing a key role across 21st century scientific development. In the face of rapid technological change, the Organisation for the Prohibition of Chemical Weapons (OPCW), the implementing body of the Chemical Weapons Convention ("the Convention"), seeks technological opportunities to strengthen capabilities in the field of chemical disarmament. The OPCW Scientific Advisory Board (SAB) in its review of developments in science and technology examined the potential uses of emerging technologies for the implementation of the Convention at a workshop entitled "Innovative Technologies for Chemical Security", held from 3 to 5 July 2017, in Rio de Janeiro, Brazil. The event, organized in cooperation with the International Union of Pure and Applied Chemistry (IUPAC), the National Academies of Science, Engineering and Medicine of the United States of America, the Brazilian Academy of Sciences, and the Brazilian Chemical Society, was attended by 45 scientists and engineers from 22 countries. Their insights into the use of innovative technological tools and how they might benefit chemical disarmament and non-proliferation informed the SAB's report on developments in science and technology for the Fourth Review Conference of the Convention (to be held in November 2018), and are described herein, as are recommendations that the SAB submitted to the OPCW Director-General and the States Parties of the Convention. It is concluded that technologies exist or are under development that could be used for investigations, contingency, assistance and protection, reducing risks to inspectors, and enhancing sampling and analysis

Metal dispersion, accessibility and catalytic activity in methane oxidation of mesoporous templated aluminosilica supported palladium

International audiencePalladium catalysts using templated mesostructured porous silicas and aluminosilicas of MCM-41 type as supports were synthesized with various metal loadings and particle sizes as well as different metal accessibilities to the reactants. The metal was deposited by reacting an aqueous solution of [Pd(NH3)4]2+ complexes with the support, the template of which was partially extracted. The evolution of the support characteristics was monitored at different steps of preparation using X-ray diffraction (XRD), N2 physisorption and transmission electron microscopy (TEM). Particle size and metal accessibility were evaluated combining information from XRD line broadening, TEM observations, UV–visible spectra and H2 uptakes. The PdO reducibility was investigated using temperature-programmed reduction (TPR). In the templated mesoporous aluminosilicate, 27Al-MAS-NMR revealed that Al3+ occupied mostly tetrahedral sites, a fraction of which adopted an octahedral environment in the presence of palladium. According to the light-off curves, the catalytic methane oxidation activity is enhanced in pure silica supports where partial pore wall collapse has occurred. In contrast, for aluminosilica supports the beneficial effect of Al3+ on metal dispersion and catalytic activity was counterbalanced by partial metal encapsulation. Optimizing palladium particle size and avoiding as much as possible metal encapsulation give rise to catalysts more active than the conventional alumina supported palladium catalysts

Oxidation of Methane to Methanol over Single Site Palladium Oxide Species on Silica: A Mechanistic view from DFT

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Graphene as a 2D Support Shuttle for Separating Photogenerated Charges: an Example combining Copper and TiO2 Nanotubes

SSCI-VIDE+CARE+FDA:CGU:GBEInternational audienceTiO2 nanotubes (NTs), even if better photocatalysts than classical 3D particles, still suffer from recombination of electron-hole pairs. In a previous study, we found that adding graphene oxide (GO) to NTs help to improve the separation of photogenerated charges. However, the driving force for the transfer of electrons from TiO2 to GO was also found to come from the reduction of functional oxygen groups on graphene layers leading to instability under irradiation. Herein, an alternative is proposed through the addition of Cu NPs onto GO without contact with TiO2 NTs leading to a physical separation of charges with GO acting here only as a 2D support shuttle without inactivation. Comparison was performed between Cu/TiO2 NTs and Cu/(R)GO/NTs systems. On Cu/TiO2 NTs, results show a stabilization of Cu NPs at a +I oxidation state due to a strong interaction with TiO2 NTs leading to photocatalytic activity under visible light for the formic acid (FA) photodegradation. On Cu/(R)GO/TiO2 systems, strong activity was observed using non-reduced GO due to a physical separation of Cu NPs and TiO2 nanotubes confirming our assumption while reducing GO leads to a relocation of Cu NPs onto TiO2 NTs and loss of any beneficial effect due to GO. Application for H2 production will also be presented

Graphene as a 2D Support Shuttle for Separating Photogenerated Charges: an Example combining Copper and TiO2 Nanotubes

SSCI-VIDE+CARE+FDA:CGU:GBEInternational audienceTiO2 nanotubes (NTs), even if better photocatalysts than classical 3D particles, still suffer from recombination of electron-hole pairs. In a previous study, we found that adding graphene oxide (GO) to NTs help to improve the separation of photogenerated charges. However, the driving force for the transfer of electrons from TiO2 to GO was also found to come from the reduction of functional oxygen groups on graphene layers leading to instability under irradiation. Herein, an alternative is proposed through the addition of Cu NPs onto GO without contact with TiO2 NTs leading to a physical separation of charges with GO acting here only as a 2D support shuttle without inactivation. Comparison was performed between Cu/TiO2 NTs and Cu/(R)GO/NTs systems. On Cu/TiO2 NTs, results show a stabilization of Cu NPs at a +I oxidation state due to a strong interaction with TiO2 NTs leading to photocatalytic activity under visible light for the formic acid (FA) photodegradation. On Cu/(R)GO/TiO2 systems, strong activity was observed using non-reduced GO due to a physical separation of Cu NPs and TiO2 nanotubes confirming our assumption while reducing GO leads to a relocation of Cu NPs onto TiO2 NTs and loss of any beneficial effect due to GO. Application for H2 production will also be presented

Influence of graphene and copper on the photocatalytic response of TiO2 nanotubes

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