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Deak A.,University of Szeged | Janovak L.,University of Szeged | Csapo E.,University of Szeged | Ungor D.,University of Szeged | And 5 more authors.
Applied Surface Science | Year: 2016

Inorganic/organic hybrid layers have been prepared having superhydrophobic as well as photoreactive properties. The hybrid thin films with micro- and nanosized dual-scale surface roughness consist of ∼25 μm layered double oxide (LDO) photocatalyst particles and low surface energy poly(perfluorodecyl acrylate) [p(PFDAc)] fluoropolymer binder material. The application of [p(PFDAc)] resulted in the decrease in the surface free energy of the hydrophilic LDO. The structured surface LDO with ∼12% ZnO phase content were synthesized from layer double hydroxide (LDH) spheres. The determined excitation wavelength and the calculated band gap energy values were 386 nm and 3.23 eV, respectively. The hybrid thin films were prepared by a simple spray-coating method, which is a low-cost, fast and scalable film-forming technique. The surface roughness and also the wetting properties of the two-component hybrid layers proved to be finely adjustable by the LDO:fluoropolymer ratio. It was found that at 80–90 wt% LDO content, the thin films with a surface free energy value of ∼12 mJ/m2 displayed superhydrophobic behaviour (Θ > 150°) with satisfactory photocatalytic properties. This means special photoreactive surfaces with superhydrophobic properties instead of the conventional superhydropilic photocatalyst layers. According to the benzoic acid photodegradation test experiments of benzoic acid, the hybrid layers with 80–90 wt% LDO content photooxidized 22–24% of the initial test molecule concentration (0.17 g/L) under UV-A (λmax = 365 nm) illumination. © 2016 Elsevier B.V.

Boda L.,MOL Hungarian Oil and Gas Company Plc | Onyestyak G.,Hungarian Academy of Sciences | Solt H.,Hungarian Academy of Sciences | Lonyi F.,Hungarian Academy of Sciences | And 2 more authors.
Applied Catalysis A: General | Year: 2010

There is strong interest in the production of fuels from triglycerides of biological origin. In this work tricaprylin (TC) and caprylic acid (CA) were used as model compounds to study the catalytic hydroconversion process of triglycerides to acyclic aliphatic hydrocarbons. Supported metal and metal oxide catalysts, such as palladium on activated carbon (Pd/C), and promoted molybdena-alumina (Ni,Mo/γ-Al2O3) were used. The reaction was found to proceed in consecutive steps: hydrogenolysis (HYS) of TC to CA and propane, followed by hydrodeoxygenation (HDO) of the CA intermediate. The overall reaction rate was governed by the rate of the HDO reaction. Two distinct HDO routes were distinguished: (i) hydrodecabonylation and (ii) reduction of oxygen. Over Pd/C the prevailing reaction route of CA hydroconversion was the decarbonylation giving mainly C7 alkane and CO, whereas the HDO over the Ni,Mo/γ-Al2O3 catalysts proceeded in consecutive H2 addition and dehydration steps giving predominantly C8= alkenes, C8 alkanes and water. In reaction route (ii) alcohol and traces of aldehyde were detected as acid-to-alkane intermediates. Results suggest that reaction route (i) passes through formic acid intermediate that, in the presence of H2, rapidly decomposes to CO and H2O. © 2009 Elsevier B.V. All rights reserved.

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