Search

Nickel-based catalysts (40 wt% Ni) with commercial silicon-aluminum oxides as supports were prepared. The variation of the silica amount (10%, 20% and 40%) was studied. These catalytic formulations were characterized by N2 adsorption, SEM/EDX, HR-TEM, XRD, LRS and XPS, and tested in the oxidative dehydrogenation of ethane (ODHE) to produce ethylene. Besides, they were compared with a nickel-based silica-supported catalyst (NiO/SiO2). The effect of the proportion of silica in the supports on the generated Ni species, and consequently on the respective catalytic performances, was investigated. The results showed that, despite of the same NiO loading in all catalysts, different NiO-support interactions and surface amounts of non-selective oxygen species were obtained. These features had an impact on the catalytic behavior of each formulation. Remarkably, while ethylene selectivity was high and almost the same, ethane conversion increased with the silica amount in the supports. On the other hand, as expected, pure silica as a support resulted in high conversion but markedly low selectivity, favoring the total ethane oxidation to carbon dioxide. This work demonstrates that it is possible to increment the alkane conversion without sacrificing the alkene selectivity by tuning the active species properties through the increase of the amount of silica in the supports.

Structured catalysts have important advantages compared to powder formulations and they are required for processes intensification. In this work, three different ceramic structures: a cordierite monolith, an alumina foam and an alumina-silica paper were used as substrates for the deposition of a NiO-Al2O3 coating and tested in the oxidative dehydrogenation of ethane to produce ethylene. For comparison, a NiO-Al2O3 powder catalyst was also prepared. Nickel oxide species with different physicochemical features were obtained over each structure, evidenced by morphological (SEM-EDX) and physicochemical characterization (XRD, LRS and XPS). The best distributions of the catalytic coatings and NiO physicochemical properties were obtained when the monolith and the foam were used as substrates. These led to higher NiO-Al2O3 interactions and consequently to high ethylene selectivity values, 70–90 %, corresponding to the former an ethane conversion of 22 % and to the latter a 5 %. The distribution of the active phase on the ceramic paper was heterogeneous, with NiO agglomerations and poor NiO-support interaction thus achieving low olefin selectivity (∼ 30 %). The addition of a second element such as cerium was also studied in those structured catalysts with high selectivity, resulting in both cases in an increment of ethane conversion but a decrease in ethylene selectivity. This behavior was attributed to the generation of electrophilic oxygen species.

Heterogeneous photocatalysis was used for the degradation and mineralization of erythromycin (ERY), with a consequent production of carboxylic acids. For that, a series of TiO2 and Ti1-xSnxO2 structured catalysts, namely M1 to M5, was prepared using the washcoating method, with the catalytic coatings being deposited onto stainless steel meshes. Besides, the catalytic activity of the prepared systems was compared to that of the commercial mesh (CM). The results showed that the prepared TiO2 structured catalyst (M1) presented better ERY oxidation than the CM one, what was associated to the higher catalyst load and to the anatase/rutile ratio. Considering the Sn-doped structured catalysts, for M2, M4 and M5 catalysts, lower ERY mineralization and high formation of carboxylic acids were found, when compared to the M3 catalyst. The improved M3 activity was attributed to the formation of a staggered gap (type II heterojunction), providing better charge separation. In this situation, a high generation of hydroxyl radicals is obtained, resulting on a higher ERY mineralization. By the obtained results it is possible to determine that the addition order and the type of Sn compound added in the washcoating process, affects the catalytic activity due to the formation of a solid solution and to the type of produced heterostructures. The M3 catalyst also showed high stability in long-term tests up to 44 h of reaction. The results provide insights into the development of an inexpensive structured catalyst production method and its influence in the stability of the photocatalyst, as well as in its applicability on water/wastewater treatment. Fil: Albornoz, L.L. Universidade Federal do Rio Grande do Sul; Brasil Fil: da Silva, S.W.. Universidade Federal do Rio Grande do Sul; Brasil Fil: Bortolozzi, Juan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; Argentina Fil: Banus, Ezequiel David. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; Argentina Fil: Brussino, Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; Argentina Fil: Ulla, Maria Alicia del H.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; Argentina Fil: Bernardes, Andrea Moura. Universidade Federal do Rio Grande do Sul; Brasil

An improvement of the photocatalytic properties of TiO2, by the doping with Sn, a non-critical raw material, was evaluated. A series of Sn-doped titania-zirconia structured photocatalysts were synthesized using the washcoating method on stainless steel meshes. Two methodologies for the Sn incorporation were applied using different Sn sources: oxalate and SnO2 (powder or nanoparticles). Coating properties were characterized by SEM-EDS, XPS and LRS techniques, and their photocatalytic performances were tested for erythromycin (ERY) oxidation. The coating synthesized with the Sn-oxalate suspension presented a more homogeneous distribution of the elements. Surface characterization showed that the Sn-doped catalysts presented a partial reduction of the Ti4+ species to Ti3+ with the presence of some oxygen vacancies, associated to an effective interaction between Ti and Sn (surface Ti1-xSnxO2-like structure). The lowest amount of these vacancies were found when the Sn source was SnO2 (powder or nanoparticles). The formation of a Ti-Sn-O solid solution decreased the recombination of the e-cb/h+vb pair, allowing better performance on the photocatalytic degradation of ERY, with 46% mineralization for the Sn doped photocatalyst and 26% for the Sn-free catalyst. The Sn addition methodology influenced the catalytic activity due to the formation of different oxidizing agents, leading to different carboxylic acids generation. The best photocatalyst presented after more than 400 h of use, a catalytic activity decreases of only 11.3% in mineralization, showing that this photocatalyst has a high catalytic stability. Besides, after a regeneration process, the catalytic activity was almost thoroughly recovered.

Structured catalysts are more suitable than powder catalysts for liquid phase reactions since their removal is simpler by avoiding filtration. In this work we present two structured catalysts consisting in CuO/TiO2-ZrO2 coated wire-meshes calcined at two different temperatures: 500 and 900 °C, Cu-TZ-W500 and Cu-TZ-W900. These catalytic systems were characterized by XRD, LRS, SEM/EDX, XPS and tested in the wet oxidation of phenol. The treated solutions were analyzed to investigate copper leaching, TOC conversion and identification of organic compounds. Powder equivalent formulations have also been prepared for comparison and analysis of substrate role. There is a clear effect of the substrate on the catalytic coating when strong calcination temperature (900 °C) is applied, by the migration of the steel components to the coating, inducing a protective effect on copper species and therefore avoiding metal leaching. This system reached 25% of conversion at 7 min, whereas this value was 100% for Cu-TZ-W500. Furthermore, the final XTOC were ∼ 42% for the first one and ∼ 79% for the second. Despite the lower XTOC obtained with Cu-TZ-W900, copper leaching was negligible. It was found that the higher reaction rate of Cu-TZ-W500 was driven by a combination of both heterogeneous and homogeneous pathways. Fil: Brussino, Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; Argentina Fil: Gross, Martin Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; Argentina Fil: Banus, Ezequiel David. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; Argentina Fil: Ulla, Maria Alicia del H.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; Argentina

In this work the catalytic performance of Cu(5%)/Al2O3 catalysts prepared by wet impregnation and calcined at three different temperatures, 400 ºC (WI 400), 650 ºC (WI 650) and 900 ºC (WI 900), was analyzed. These materials were tested in the phenol wet oxidation reaction using H2O2 (0.22 or 0.88 M) as an oxidizing agent, 1000 mg/L of phenol at 70 °C and atmospheric pressure. A complete conversion of phenol and a high extent of phenol mineralization were obtained for the three catalysts. Surface Cu2+ species suffered a reduction process during the catalytic reaction due to the drop of the pH value and a fraction of the reduced copper was leached to the liquid phase. Despite this, the increment in the calcination temperature produced a decrease in this reduction extent, inducing a protective effect to the Cu2+ species through the interaction between these and the support. Moreover, the existence of Cu-Al-O interactions not only diminished Cu2+ species reduction but also their leaching. Even though the WI 900 catalyst presented the lower leaching extent (36%), the remaining amount of copper in the solution still exceeded the allowed limit value for drinking water (1 mg Cu/L). Fil: Devard, Alejandra Veronica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; Argentina Fil: Brussino, Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; Argentina Fil: Marchesini, Fernanda Albana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; Argentina Fil: Ulla, Maria Alicia del H.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; Argentina

In the present work different amounts of lanthanum were added to Ni/Al 2 O 3 cordierite monoliths with the objective to enhance the catalytic performance of the un-promoted structured catalyst in the oxidative dehydrogenation of ethane (ODE). The impact of the amount of promoter on the catalytic performance of the structured catalysts is discussed through the use of different characterization techniques: LRS, FTIR, Py-TPD, TPR, XPS and SEM-EDX. The incorporation of La was found to increase ethane conversion by an increase in the reducibility of Ni species, with a drop in the ethylene selectivity. Despite this drop, at constant reaction temperature the olefin selectivity maintained a constant value with the increase of ethane conversion, generating a beneficial effect in these catalysts. The presence of La generated: i) a new type of Ni 2+ species due to Ni-La-O interactions and ii) La-Al-O species, which moderated the Ni-Al ones promoting the drop of the ethylene selectivity. Both species also modify the total acidity and reduce the strong acid sites, preventing ethylene oxidation. Thus, as the ethylene production increases, its selectivity remains invariant. An optimal La/Ni ratio was found around 0.08, which generated appropriate interactions among the active species, boosting the ethylene yield at 400 °C by 2.7 times from 4.9% (un-promoted structured catalyst, Ni-M) to 13.4% (NiLa-M, La/Ni: 0.08). Fil: Brussino, Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; Argentina Fil: Bortolozzi, Juan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; Argentina Fil: Dalla Costa, B.O.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; Argentina Fil: Banus, Ezequiel David. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; Argentina Fil: Ulla, Maria Alicia del H.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; Argentina

This paper investigates the oxidative dehydrogenation of ethane to produce ethylene at low temperatures (500 &deg, C) in metallic structured substrates. To check this point, the FeCrAlloy&reg, monoliths with different channel sizes (289&ndash, 2360 cpsi) were prepared. The monoliths were coated with a Ni/Al2O3 catalyst (by washcoating of alumina and the latter nickel impregnation) and characterized by Scanning Electron Microscopy and Energy-Dispersive X-ray analysis (SEM-EDX), Temperature-Programmed Reduction (TPR), X-ray Diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS). The catalytic results showed that all monoliths coated with ~300 mg of catalyst presented similar ethane conversion (15%) at 450 &deg, C. However, the lowest selectivity to ethylene was found for the monolith with the lower channel size and the higher geometric surface area, where a heterogeneous catalyst layer with Ni enriched islands was generated. Therefore, it can be said that the selectivity to ethylene is linked to the distribution of Ni species on the support (alumina). Nevertheless, in all cases the selectivity was high (above 70%). On the other hand, the stability in reaction tests of one of the coated monoliths was done. This structured catalyst proved to be more stable under reaction conditions than the powder catalyst, with an initial slight drop in the first 8 h but after that, constant activity for the 152 h left.

The present work investigates the preparation of NiCe/γ-Al2O3 coated cordierite monoliths for oxidative dehydrogenation of ethane (ODE) reaction through a two steps procedure: the primer deposition of a γ-Al2O3 coating consisting in a mixture of micro and nanoparticles via the washcoating method and the latter incorporation of the active phase by impregnation. Moreover, a modification in these two steps was made: the suppression of some calcination steps to save energy in the manufacture process. The structured catalysts, named as Ni(X)Ce(Y)-M, where X = 13 or 19 wt%. Ni and Y = 5 or 8 wt%. Ce respectively, with respect to the alumina loading, were characterized by SEM/EDX, XRD, FTIR, LRS and XPS, and their catalytic activity was tested in the ODE reaction. Furthermore, their mechanical resistance to vibration was studied. Similar results corresponding to the un-promoted system are also presented for comparison. It was found that the co-impregnation of nickel and cerium was affected by the suppression of some calcinations: a preferential absorption of Ce rather than Ni occurred, generating at the end a catalytic coating with a higher Ce/Ni ratio than that of the precursor solution and a lower Ni loading than that of Ni(13)-M. On the other side, in the NiCe-based catalysts the properties of the active sites remained the same despite the increment in the active phase, at a fixed Ce/Ni nominal atomic ratio of 0.17. In the case of the Ni(19)Ce(8)-M system, although the Ni/Al atomic ratios were found lower than those of the nominal ones by EDX and XPS and ethylene selectivity decayed, ethane conversion resulted markedly higher, leading to an improved ethylene yield. Fil: Brussino, Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; Argentina Fil: Bortolozzi, Juan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; Argentina Fil: Milt, Viviana Guadalupe. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; Argentina Fil: Banus, Ezequiel David. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; Argentina Fil: Ulla, Maria Alicia del H.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; Argentina

Different strategies for the generation of Ni (15 wt.%)/Al2O3 catalytic coatings onto cordierite monoliths applied to the oxidative dehydrogenation of ethane (ODHE) were investigated. Strategy 1 involved the deposition of an alumina layer (nanoparticles or micro + nanoparticles) and the later incorporation of the active phase. Strategy 2 employed a suspension containing a powder catalyst that was used to deposit the catalytic film. Morphological (SEM) and physicochemical (LRS and XPS) characterizations were used to explain the catalytic performance of the structured systems. The NiO particles distribution on the catalytic coatings obtained was analyzed via SEM-EDX performed in different monolith regions. The ultrasonic test was used to evaluate the anchoring of these catalytic films to the substrates. It was concluded that the selection of both the strategy and the particle size of the support is extremely important in order to obtain a homogeneously dispersed, accessible and highly adhered to the substrate catalyst. Fil: Brussino, Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; Argentina Fil: Bortolozzi, Juan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; Argentina Fil: Milt, Viviana Guadalupe. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; Argentina Fil: Banus, Ezequiel David. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; Argentina Fil: Ulla, Maria Alicia del H.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; Argentina