Advice from the Scientific Advisory Board of the Organisation for the Prohibition of Chemical Weapons on riot control agents in connection to the Chemical Weapons Convention

Compounds that cause powerful sensory irritation to humans were reviewed by the Scientific Advisory Board (SAB) of the Organisation for the Prohibition of Chemical Weapons (OPCW) in response to requests in 2014 and 2017 by the OPCW Director-General to advise which riot control agents (RCAs) might be subject to declaration under the Chemical Weapons Convention (the Convention). The chemical and toxicological properties of 60 chemicals identified from a survey by the OPCW of RCAs that had been researched or were available for purchase, and additional chemicals recognised by the SAB as having potential RCA applications, were considered. Only 17 of the 60 chemicals met the definition of a RCA under the Convention. These findings were provided to the States Parties of the Convention to inform the implementation of obligations pertaining to RCAs under this international chemical disarmament and non-proliferation treaty.Peer reviewe

Influence of Graphene and Copper on the Photocatalytic Response of TiO2 Nanotubes

SSCI-VIDE+CARE:ECI2D+MHM:FDA:CGU:GBEInternational audience1D nanotubular TiO2 are known to improve photocatalytic performance compared to classical 3D particles. Combination of TiO2 nanotubes (NTs) with graphene oxide (GO) was previously envisaged to limit the recombination of e--h+ pairs (Appl. Cat. B 2017, 209, 203-213). Compared to non-reduced GO, improvement in activity was noticed if partially reduced GO was used due to a decrease in charge transfer resistance after partial reduction limiting the recombination phenomenon. If GO was totally reduced, the gain in activity was lost suggesting that the driving force for the injection of electrons from TiO2 to GO comes from the consumption of oxygen groups on graphene layers. The present study proposes an alternative for avoiding the consumption of photoelectrons through the addition of Cu NPs onto GO without contact with TiO2 NTs. Such a building is facilitated by the tendency of GO to wrap up around TiO2 NTs. Comparison was herein 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 a 80% increase in activity for formic acid (FA) degradation under UV. TiO2 NTs are also necessary in combination with Cu to acquire an enhanced photocatalytic response in the visible region or for the production of H2. Contrary to GO/TiO2 NTs, in the presence of Cu, addition of non-reduced GO leads to a 250% increase in activity compared to TiO2 NTs alone for FA photodegradation while the use of partially reduced GO leads to a similar photocatalytic response than with Cu/TiO2 NTs alone. This effect is due to a partial dislocation of the graphene layers wrapped around TiO2 NTs leading to a preferential relocation of Cu NPs directly onto TiO2 NTs

Influence of Graphene and Copper on the Photocatalytic Response of TiO2 Nanotubes

SSCI-VIDE+CARE:ECI2D+MHM:FDA:CGU:GBEInternational audience1D nanotubular TiO2 are known to improve photocatalytic performance compared to classical 3D particles. Combination of TiO2 nanotubes (NTs) with graphene oxide (GO) was previously envisaged to limit the recombination of e--h+ pairs (Appl. Cat. B 2017, 209, 203-213). Compared to non-reduced GO, improvement in activity was noticed if partially reduced GO was used due to a decrease in charge transfer resistance after partial reduction limiting the recombination phenomenon. If GO was totally reduced, the gain in activity was lost suggesting that the driving force for the injection of electrons from TiO2 to GO comes from the consumption of oxygen groups on graphene layers. The present study proposes an alternative for avoiding the consumption of photoelectrons through the addition of Cu NPs onto GO without contact with TiO2 NTs. Such a building is facilitated by the tendency of GO to wrap up around TiO2 NTs. Comparison was herein 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 a 80% increase in activity for formic acid (FA) degradation under UV. TiO2 NTs are also necessary in combination with Cu to acquire an enhanced photocatalytic response in the visible region or for the production of H2. Contrary to GO/TiO2 NTs, in the presence of Cu, addition of non-reduced GO leads to a 250% increase in activity compared to TiO2 NTs alone for FA photodegradation while the use of partially reduced GO leads to a similar photocatalytic response than with Cu/TiO2 NTs alone. This effect is due to a partial dislocation of the graphene layers wrapped around TiO2 NTs leading to a preferential relocation of Cu NPs directly onto TiO2 NTs

Dehydrogenation of methylcyclohexane to toluene over partially reduced Mo–SiO2 catalysts

Dehydrogenation of methylcyclohexane (MCH) has been carried out on a variety of partially reduced Mo(x)–SiO2 (x: Mo/Si molar ratio × 100) catalysts differing by the molybdenum loading and which were prepared by sol–gel method. The objective was to maximize hydrogen production by monitoring the selectivity toward toluene formation. The MCH dehydrogenation was carried out in a down-flow reactor at 673 K and 2.2 MPa of total hydrogen pressure. The effect of Mo molar loading on the structure of the catalysts was studied by N2 physisorption, TPR, XRD, UV–vis DRS, NH3-TPD, XPS and TEM techniques. From the activity tests, it was concluded that Mo10–SiO2 catalyst, with Mo molar ratio of 10, exhibited the highest activity and the largest yield of toluene thanks to the existence of a good compromise between reduced Mo species and bulk MoO3. An increase of the molybdenum loading from 10 to 15 (molar ratio) led to: (i), the formation of non-active MoO3 phase; (ii), a low stable molybdenum species during on-stream operation; and (iii), a large coke formation due to an increase of the catalyst acidity.Thanks to the Tunisian Ministry of Higher Education, Scientific Research and Information and communication Technologies funds for financial support. This study is also partially supported by The Spanish Ministry of Science and Innovation (ENE2007-67533-C02-01 project) and The Community of Madrid (S2013/MAE 2882 project).Peer Reviewe