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- ItemSelf-propelled micromotors for cleaning polluted water(Washington, DC : ACS, 2013) Soler, L.; Magdanz, V.; Fomin, V.M.; Sanchez, S.; Schmidt, O.G.We describe the use of catalytically self-propelled microjets (dubbed micromotors) for degrading organic pollutants in water via the Fenton oxidation process. The tubular micromotors are composed of rolled-up functional nanomembranes consisting of Fe/Pt bilayers. The micromotors contain double functionality within their architecture, i.e., the inner Pt for the self-propulsion and the outer Fe for the in situ generation of ferrous ions boosting the remediation of contaminated water.The degradation of organic pollutants takes place in the presence of hydrogen peroxide, which acts as a reagent for the Fenton reaction and as main fuel to propel the micromotors. Factors influencing the efficiency of the Fenton oxidation process, including thickness of the Fe layer, pH, and concentration of hydrogen peroxide, are investigated. The ability of these catalytically self-propelled micromotors to improve intermixing in liquids results in the removal of organic pollutants ca. 12 times faster than when the Fenton oxidation process is carried out without catalytically active micromotors. The enhanced reaction-diffusion provided by micromotors has been theoretically modeled. The synergy between the internal and external functionalities of the micromotors, without the need of further functionalization, results into an enhanced degradation of nonbiodegradable and dangerous organic pollutants at small-scale environments and holds considerable promise for the remediation of contaminated water.
- ItemDirect chemical vapor deposition synthesis of large area single-layer brominated graphene(Cambridge : Royal Society of Chemistry, 2019) Hasan, M.; Meiou, W.; Yulian, L.; Ullah, S.; Ta, H.Q.; Zhao, L.; Mendes, R.G.; Malik, Z.P.; Ahmad, N.M.; Liu, Z.; Rümmeli, M.H.Graphene and its derivatives such as functionalized graphene are considered to hold significant promise in numerous applications. Within that context, halogen functionalization is exciting for radical and nucleophilic substitution reactions as well as for the grafting of organic moieties. Historically, the successful covalent doping of sp2 carbon with halogens, such as bromine, was demonstrated with carbon nanotubes. However, the direct synthesis of brominated graphene has thus far remained elusive. In this study we show how large area brominated graphene with C-Br bonds can be achieved directly (i.e. a single step) using hydrogen rich low pressure chemical vapor deposition. The direct synthesis of brominated graphene could lead to practical developments. © The Royal Society of Chemistry.