Synthesis of Au-Cu/SBA(Ti) catalysts for photocatalytic applications

In this work, it has been synthesized several Au and Au-Cu alloy photocatalysts supported on two different mesoporous supports: a non-commercial SBA-15 and a post-synthesis TiO2 modified SBA-15 (TiSBA-15), with which a high dispersion of TiO2 species have been achieved maintaining the SBA-15 structure. In addition, it has also been obtained highly dispersed Au nanoparticles confined in SBA-15 pore channels. The photocatalysts have been preliminary tested in the preferential CO oxidation in a H2-rich stream (CO-PROX) at room temperature and atmospheric pressure under simulated solar light irradiation. In spite of the very low gold and copper loading (1.5 wt% and 0.5wt% respectively), the catalysts resulted active and selective in the low temperature photo-CO-PROX.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Au-Cu/SBA(Ti) based catalysts for photocatalytic applications

Comunicación a congresoIn this work, it has been synthesized several Au and Au-Cu alloy photocatalysts supported on two different mesoporous supports: a non-commercial SBA-15 and a post-synthesis TiO2 modified SBA-15 (TiSBA-15), with which a high dispersion of TiO2 species have been achieved maintaining the SBA-15 structure. In addition, it has also been obtained highly dispersed Au nanoparticles confined in SBA-15 pore channels, as can be observed in Figure 1. The photocatalysts have been preliminary tested in the preferential CO oxidation in a H2-rich stream (CO-PROX) at room temperature and atmospheric pressure under simulated solar light irradiation. In spite of the very low gold and copper loading (1.5 wt% and 0.5wt% respectively), the catalysts resulted active and selective in the low temperature photo-CO-PROX.Universidad de Málaga, Campus de Excelencia Internacional Andalucía Tec

Pt-Fe2O3 based catalysts for anisole hydrodeoxygenation

The depletion of fossil fuels along with massive emissions of greenhouse gases (GHG) emissions are serious issues facing society nowadays. Considering that almost a quarter of fossil fuel consumption is associated with the transport sector, the scientific community has focused a great deal of its research to the quest of alternative environmentally friendly technologies and products with minimum GHG emissions derived from renewable energy sources. In this context, lignocellulosic biomass has demonstrated a great potential, since from its fast pyrolysis a bio-oil with interesting properties can be obtained to be used as liquid fuel for internal combustion engines. However, this bio-oil contains a considerable percentage of water and oxygenated compounds that impoverishes its quality making it unstable, acid, corrosive and with low calorific value. Thus, hydrotreating technologies like hydrodeoxygenation reaction are essential to upgrade bio-oil by means of removing oxygen from oxygenated compounds. The hydrodeoxygenation reaction usually takes places at high temperature and moderate hydrogen pressure, in the presence of a bifunctional catalyst that, on the one hand, promotes the oxygen removal with acid sites and, on the other hand, activates the hydrogen molecule in metallic hydrogenating sites. Regarding the latter function, noble metals like Pt, Ru or Pd have demonstrated outstanding hydrogenation capability even with low metal loading. To maximise metal dispersion, these noble metals are supported on mesoporous solids that in turn provide the moderate acidity necessary to remove oxygen heteroatom. In this work, supported Pt on Fe2O3-containing SBA-15 were tested in the HDO reaction of anisole at 275 ºC and 30 bar in a fixed-bed reactor in continuous down flow. Pt was added in 1 wt. % as the hydrogenating metal and different Fe2O3 loadings (5 wt. %, 15 wt. % and 30 wt. %) as the oxyphilic and acid counterpart.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Nanoestructuras de ceria-titania para fotodegradar azul de metileno con luz solar simulada

En los últimos años la protección ambiental y el uso de fuentes de energía renovables son dos objetivos principales en la investigación química. La energía solar se puede aprovechar para la degradación fotocatalítica de moléculas orgánicas contaminantes, hormonas o medicamentos, tanto en el aire, en el agua, como en las superficies, porque la luz solar es capaz de descomponerlas [1]. A pesar de la gran cantidad de aplicaciones fotocatalíticas de la titania (TiO2), fotocatalizador no tóxico, de bajo costo y muy prometedor [2], hay algunos factores críticos que limitan su fotoactividad. El principal es el valor de su salto de energía, que limita su uso como fotocatalizador en la región UV del espectro. Con el objetivo principal de extender su uso a la región visible del espectro, en literatura se ha propuesto el depósito de metales nobles en su superficie, modificaciones superficiales, así como el dopaje con iones de metales de transición o elementos de tierras raras. En este sentido, el uso de ceria (CeO2) ha atraído una gran atención debido a propiedades como su biocompatibilidad, inercia química así como su actividad en reacciones de oxidación, relacionada con la formación vacantes de oxígeno en su superficie [3]. Se ha comprobado que el sistema oxídico mixto CeO2-TiO2 es más fotoactivo que la titania pura debido a la disminución del salto de energía y a la mejora en la movilidad de los excitones. Este trabajo tiene como objetivo desarrollar fotocatalizadores basados en nanoestructuras de titania que sean activas en el visible, dopando la matriz de titania con cerio. Principalmente se pretende evaluar tanto el papel del cerio como la morfología del nanomaterial en la respuesta fotocatalítica bajo luz UV y solar.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Creating customer value through service experiences: an empirical study in the hotel industry

The main research objectives of this paper are: first, to identify the three levels of a service evaluation: attributes (service value), outcome (service experience), and values (developing service relationships); secondly, to differ and to relate the perceptions of service value with service experience components. According to the ‘theory of cognitive schemata’ and the ‘means-end theory’, the components of a service experience are hierarchical in nature. Thus, customers evaluate their experiences – and build their service relationships – taking into account not only the attributes of the service (first level of abstraction), but also the outcomes and consequences that those attributes cause on them (highest level of abstraction). Marketing research has been mostly focused on the detection of affective aspects of quality and satisfaction. However, little attention has been devoted to the cognitive organization of the structure of evaluative judgments in the customer’s mind. According to our results, servicescape provides the strongest driver of service value when creating service experiences, followed by service equity. Elements such as the service atmosphere, hotel facilities, etc. are significant contributors to customer’s easiness to relax and escape from routine, which are the two major factors in the service experience. Similarly, hotel managers should take note of the importance of service equity by developing strong brand images which capitalize on customer’s experiences rather than service attributes

Silica-Related Catalysts for CO2 Transformation into Methanol and Dimethyl Ether

The climate situation that the planet is experiencing, mainly due to the emission of greenhouse gases, poses great challenges to mitigate it. Since CO2 is the most abundant greenhouse gas, it is essential to reduce its emissions or, failing that, to use it to obtain chemicals of industrial interest. In recent years, much research have focused on the use of CO2 to obtain methanol, which is a raw material for the synthesis of several important chemicals, and dimethyl ether, which is advertised as the cleanest and highest eciency diesel substitute fuel. Given that the bibliography on these catalytic reactions is already beginning to be extensive, and due to the great variety of catalysts studied by the dierent research groups, this review aims to expose the most important catalytic characteristics to take into account in the design of silica-based catalysts for the conversion of carbon dioxide to methanol and dimethyl ether

Ruthenium incorporation into hydrotalcites-derived mixed oxides for phenol hydrogenation: Role of Mg/Al molar ratio

In this work the catalytic behaviour of Ru supported on mixed oxides derived from non-commercial hydrotalcites in phenol hydrogenation was studied in a batch reactor working at 30 bar and 200 °C. To this end, a set of catalysts with 2 wt% Ru and a Mg/Al molar ratio of 1, 2, 3 and 4 was synthesized. The catalysts were tested in phenol hydrogenation to assess the influence of Mg/Al ratio on the catalytic performance in terms of conversion and selectivities to cyclohexanol and cyclohexanone. Physicochemical characterization was performed by X-ray Diffraction (XRD), N2 adsorption-desorption isotherms, dispersive X-ray spectroscopy in scanning transmission electron microscopy (EDS-STEM), CO chemisorption at 35 °C, CO2 and NH3 thermoprogrammed desorption (TPD) and X-ray Photoelectron Spectroscopy (XPS). The Mg/Al molar ratio employed determined the catalytic response of the resulting catalysts, obtaining the best catalytic performance (95.9 % conversion and 47.4 % cyclohexanone selectivity) with the sample with the lowest Mg/Al ratio, RuMA1. XRD results showed that in RuMA1 catalyst the hydrotalcite structure was completely transformed into the corresponding mixed oxide after thermal treatment and was also the only one in which MgAl2O4 spinel was not formed. In addition, RuMA1 presented the highest specific surface area, the greatest Ru dispersion, as evidenced by CO-chemisorption and EDX-STEM analysis, as well as a good balance between basic and acid sites and a greater proportion of Bronsted acid sites that also explain it greater selectivity to cyclohexanol.This publication is part of the R&D project PID2021-126235OB-C32 funded by MCIN/ AEI/10.13039/501100011033/ and FEDER funds. Funding for open access charge: Universidad de Málaga / CBUA. IBM thanks University of Malaga for a postdoctoral grant

Materials Design for N2O Capture: Separation in Gas Mixtures

The adsorption of greenhouse gases (GHG) as a method to reduce their emissions into the atmosphere is an alternative that is easier to implement industrially and cheaper than other existing technologies, such as chemical capture, cryogenic separation, or membrane separation. The vast majority of works found in the literature have focused their efforts on capturing CO2 as it is the largest GHG. However, although N2O emissions are not as large as CO2, the impact that N2O has on the stratosphere and climate is much larger in proportion, despite which there is not much research on N2O capture. Since both gases are usually emitted into the atmosphere together (along with other gases), it is necessary to design selective adsorbents capable of capturing and separating these gases from each other and from other gases, to mitigate the effects of climate change. This review aims to compile the existing information to date on porous adsorbents, the characteristics of the N2O adsorption processes and, above all, aims to focus the reader’s gaze on the importance of designing selective adsorbents for greenhouse gas mixtures.Partial funding for open access charge: Universidad de Málag