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Catalysts 11(11), 1325 (1-15) (2021). doi:10.3390/catal11111325, This study presents information about crystal imperfections in the main phase of industrial vanadium phosphorous oxide catalysts that are used to catalyze the oxidation of n-butane to maleic anhydride, being an important intermediate in the chemical industry. The mechanism of this reaction is still debated, and the catalytically active and selective surface centers have not yet been identified. The results presented are based on X-ray diffraction data obtained by both laboratory-scale and synchrotron powder diffraction experiments, as well as laboratory-scale single-crystal diffraction experiments. It has been proven that pronounced Bragg reflection broadening effects found in laboratory-scale powder diffraction patterns of industrial VPO catalysts are real and not due to an insufficient 2-�� resolution of the apparatus. In the framework of this work, a powder diffraction full profile fitting strategy was developed using the TOPAS software, which was applied to analyze the X-ray diffraction data of four differently activated industrial catalyst samples, originating from one batch after they had been catalytically tested. It was found that the reflection broadening is mainly caused by an anisotropic crystal size, which results in platelet-shaped crystallites of vanadyl pyrophosphate. A further contribution to the reflex broadening, especially for (111), was found to be a result of stacking faults perpendicular to the a direction in the crystal structure of vanadyl pyrophosphate. These results were used to elaborate on possible correlations between structural proxies and catalytic performance. A direct correlation between the extension of coherently scattering domains in the z direction and the catalyst���s selectivity could be proven, whereas the activity turned out to be dependent on the crystallite shape. Regarding the phase contents, it could be shown that sample catalysts containing a higher amount of ��-VO(PO$_3$)$_2$ showed increased catalytic activity., Published by MDPI, Basel

62 p., El presente trabajo, consiste en el desarrollo del análisis arquitectónico y audiovisual de distintos videoclips, pertenecientes a una nueva generación de artistas, conocida como género urbano, buscando como objetivo profundizar en la relación entre la arquitectura contemporánea y la producción musical urbana. Para ellos, se seleccionarán distintas obras audiovisuales, situadas concretamente en España, y consideradas las más representativas a la hora de vincular estos dos fenómenos artísticos. Para contextualizar el tema, se realizará un estudio sobre la historia del videoclip, esencialmente su tratamiento espacial, así como de su interesante vinculación con la arquitectura, a lo largo de la evolución del desarrollo tecnológico. También se establecerán las bases y orígenes del género musical urbano, y su estrecha relación política y social, para culminar con la comprensión de distintos casos de estudio. Además, se tratará de generar, a partir de una base teórica lo suficientemente sólida, la relación entre el espacio urbano y la arquitectura mediante esta nueva ola de artistas, que configuran el resultado e un tejido económico, social y político del mundo capitalista postindustrial., The present work will be developed with the objective of analysed the architecture and audiovisual content of diferente videoclips, belonging to a new generation of artista, who belong to the urban genre. The main objective is to go in depth in the relationship between contemporary architecture and urban music production. To achieve this, different audiovisual works are selected, specifically located in Spain, which are considered the most representative when it comes to link the artistic phenomena mentioned. To contextualize the topic, a study of the history of the music video will be developed as well as his vinculation with the architecture along his technological development. Also, there will be stabilized the bases and origins of the music urban genre and his close social and political relationship to reach the understanding of the different studied cases. Furthermore, there will be tried to generate, based on theorical bases sufficiently strong, the relationship between urban space and architecture and this new wave of artista who configure the result of an economic, politic and social fabric of the post-industrial capitalist world., Grado en Fundamentos de Arquitectura y Urbanismo

A catalyst 0.1VP(0.2)O-Cr(0.01)-PEG(1 × 10−4)/Ti for low-temperature SCR de-NOx was developed and the effects of SO2 and water vapor on its catalytic activity were investigated. Cr doping increases the molar ratio of V5+ to V4+ on the VPO catalyst, which promote oxidation of NO to NO2 and catalytic activity of the VPO catalyst. An appropriate amount of redox-coupled V5+/V4+ also promotes catalytic activity of the VPO catalyst. The denitration efficiency over 0.1VP(0.2)O-Cr(0.01)-PEG(1 × 10−4)/Ti was above 98% at 150–350°C. Cr doping also promotes the generation of Lewis acid around V5+ center and Brønsted acid (P-OH) on the VPO catalysts. The strong surface acidity of 0.1VP(0.2)O-Cr(0.01)-PEG(1 × 10−4)/Ti could restrain the adsorption of and oxidation of SO2. Characterization (FT-IR, TG) results indicate that nearly no sulfate was deposited on the surface of 0.1VP(0.2)O-Cr(0.01)-PEG(1 × 10−4)/Ti after activity test. The competitive adsorption of water molecules and nitric oxide on the catalyst surface decreases the catalytic activity of the VPO catalyst. The addition of Cr and PEG could increase the surface area and the exposure of active site of VPO catalyst, which also increase the unoccupied active sites of VPO catalysts in the presence of water vapor. The catalyst 0.1VP(0.2)O-Cr(0.01)-PEG(1 × 10−4)/Ti for low-temperature SCR de-NOx shows high catalytic activity and exhibits high resistance to SO2 and water vapor.

Two VPO materials with fibrillar morphology have been prepared by the aid of electrospinning technique. One is a VPO carbon-supported material (VCF200) with fibrous morphology and very high surface area that is stable under oxidizing conditions up to 350C. The other material is a bulk mixed VPO oxide (VPO500) with fibrous structure obtained after optimizing the calcination of the carbon support in VCF200. Despite it is a bulk oxide material, this material exhibits a high surface area (> 60 m2/g). The redox behavior of both samples was monitored by in situ Raman spectroscopy under oxidation/reduction cycles. For the dehydrated supported sample (VCF200), the pyrophosphate phase (VO)2P2O7 (Raman ~930 cm-1) is detected, which has been described as the active phase (see Figure (a) below). This phase is quite stable since it does not disappear upon subsequent oxidation/reduction cycles. Under reduction conditions at 125C, in consecutive cycles, additional Raman bands appear at ~1090 cm-1 that are characteristic of the αII-VOPO4 phase. On the other hand, the bulk phases show a reversible behavior under redox cycles (Figure (b)). Under reducing conditions, a Raman band appears at ~980 cm-1 (β-VPO phase), whereas under oxidation conditions some segregation to VOx oxides occurs. Nevertheless, this segregation is reversible and the β-VPO phase forms again under reducing conditions. Thus, these results demonstrate that the active VPO phases of these fibrous catalysts are quite stable, and that their structure is reversible under several redox cycles, which make them suitable as oxidation catalysts. Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech.

The present work addresses the issue of the promoter effect produced by group VIB elements added to the basic VPO formulation using different methods and loads in order to obtain information linking the catalytic behavior of the solids with their physicochemical properties. The unpromoted VPO precursor (VOHPO4·1/2H2O) was prepared from V 2O5 reduced with an alcoholic mixture and 100% H 3PO4. Cr, Mo or W were either impregnated on the VPO precursor or co-precipitated during the precursor synthesis. The precursors containing varying loads of the promoter were activated following a standard procedure in the same flow micro-reactor where the catalytic performance was evaluated. The precursors and the catalysts were characterized by X-ray diffraction (XRD) and laser Raman spectroscopy (LRS). Acetonitrile was used as a probe molecule to test the strength of the Lewis acid sites monitored by FTIR. The amount of chemisorbed acetonitrile was measured in a standard high vacuum system. The addition of the promoters invariably increased the catalytic activity but in every case there was an optimum load to achieve the best selectivity. The origin of this maximum could be ascribed to the right balance between the presence of very strong Lewis acid sites and the development of V5+ isolated sites in the matrix of the vanadyl pyrophosphate, by far the major crystalline phase present in the catalyst. The three group VIB promoters affect the balance between acid and redox properties but increase the overall activity in all cases. Fil: Pierini, Beatriz T.. 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: Lombardo, Eduardo Agustin. 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