Ana Raquel De la Osa (original) (raw)

Uploads

Papers by Ana Raquel De la Osa

EDULEARN18 Proceedings, 2018

EDULEARN proceedings, Jul 1, 2022

Molecular Catalysis, 2021

Abstract This study reports the electrochemical activation (EPOC) of ruthenium catalyst film with... more Abstract This study reports the electrochemical activation (EPOC) of ruthenium catalyst film with alkaline ion conductors for hydrogen production via catalytic decomposition of ammonia. Two electrocatalysts, Ru/Na-βAl2O3 and Ru/K-βAl2O3 have been prepared, characterized, and tested under low temperature reaction conditions (250–350 °C). The electrochemically supply of moderate amounts of alkaline ions (Na+ and K+) from the solid electrolyte support to the ruthenium catalyst film, activated the hydrogen production rate. The promotional effect has been attributed to a strengthening of the chemisorptive bond of weakly adsorbed N surface species, which stabilizes N adsorbed molecules on the ruthenium catalyst surface and thus facilitating the ammonia decomposition reaction. Among the two alkali ions, the effect of potassium was stronger, increasing the hydrogen production rate above 230% at 300 °C under optimally conditions. Temperature programmed reaction experiments also confirms the interest of EPOC for the activation of the catalyst at low temperatures.

Applied Catalysis B: Environmental, 2015

This study reports the feasibility of high purity H 2 production by means of the electrochemical ... more This study reports the feasibility of high purity H 2 production by means of the electrochemical reforming of biomass derived organic alcohols (methanol, ethanol and ethylene glycol)-water solutions in a proton exchange membrane (PEM) electrolysis cell. For that purpose, a nanostructured bimetallic carbonsupported Pt-Sn catalyst, with nominal Pt/Sn atomic ratios of 70/30, was synthesized by a modified polyol reduction method and characterized by means of TEM, XRD and XPS analysis. The resulting Pt 7-Sn 3 /C catalyst consists of a bi-phase Pt/SnO x structure and presents a narrow particle size distribution with size predominantly in the order of 4.5 nm, showing high dispersion on carbon support (20 wt.% metal loading). During electrochemical reforming tests, the influence of reaction temperature and the electrocatalytic stability of the system were verified for mild working operation times. Synthesized 20 wt.% Pt 7-Sn 3 /C anodic catalyst provided a promising electro-catalytic activity, comparable to that of commercial 60 wt.% Pt-Ru/C and required lower amounts of Pt in order to produce the same amount of hydrogen. Proposed system allowed to produce H 2 with a lower electrical energy requirement (26 kWh kg H 2 −1 even after deactivation), in comparison with commercial PEM water electrolyser stacks (50 kWh kg H 2 −1). In addition, obtained H 2 purity was very high (99.938%) and only few ppm of CO and CO 2 were detected at the cathode chamber. These results demonstrated the potential interest of Pt 7-Sn 3 /C anodic catalyst, synthesized via the polyol method, for production of pure hydrogen from biomass-derived compounds via electrochemical reforming at low temperatures.

Topics in Catalysis, 2017

Chemistry of Silica and Zeolite-Based Materials, 2019

Abstract With the current background of the growing global demand for liquid fuels and increasing... more Abstract With the current background of the growing global demand for liquid fuels and increasing environmental concerns, fuels free of sulfur, nitrogen, and aromatics, produced by Fischer–Tropsch synthesis, may easily meet increasingly stringent regulations and energy sustainability. It is therefore desirable to look for potential materials that can eliminate some of the drawbacks inherent to the reaction. Increasing the catalytic activity implies the rational design of catalysts with well-defined active phases and promoters or with new supports. In addition, for industrial scale production, these materials should provide adequate mechanical properties at reasonable cost, high thermal conductivity, and chemical inertness to ensure an easy recovery of both the active phase and support without the need for severe processes. As such, this chapter explores prospective technologies on catalyst design with emphasis on the development of β-silicon carbide heterogeneous catalyst systems with potential for optimizing fuel yield.

Sustainable Chemistry and Pharmacy, 2022

Computer Applications in Engineering Education, 2020

Dynamic simulation has been incorporated into Chemical Engineering Master at the University of Ca... more Dynamic simulation has been incorporated into Chemical Engineering Master at the University of Castilla-La Mancha as a teaching tool together with working cases. Concretely, this study presents the activities, evaluating criteria and a set of case of studies performed by master students in the process dynamic and industrial plants control course. It is described in detail, the Aspen HYSYS® simulations carried out to study the influence of main tuning parameters of proportional, integral, and derivative controllers (gain, integral time, and derivative time) and other relevant parameters such dead-time, amplitude, or period of sine wave disturbances. The dynamic simulation helps the students to understand the previously mentioned concepts, analyzing their effect in the realistic behavior and control of simple processes. Finally, anonymous online surveys were conducted to evaluate the effectiveness of the proposed training activities and methodology. Students felt that Aspen HYSYS enhances the control theory understanding from a chemical engineering perceptive, eliminating the tediousness and time-consuming aspect of process calculation. Thus, this learning methodology promotes a successful achievement of learning outcomes. K E Y W O R D S dynamic analysis tool, master chemical engineering, process control tuning, sine wave disturbances, study cases

Journal of Chemical Education, 2021

Serious game-based learning coupled with just-intime teaching strategies was applied by offering ... more Serious game-based learning coupled with just-intime teaching strategies was applied by offering six different questionnaires to evaluate student knowledge about the safety issues and theoretical concepts and protocols of laboratory exercises. The questionnaires were presented with an appearance similar to that of computer games by means of the Kahoot! platform. Passing the safety questionnaire was mandatory, and high scores were achieved by all the students, ensuring they all properly knew the laboratory safety rules. We consider this point essential in chemistry and engineering education, because future professionals must be aware of the importance of safety. In addition, responses to the questionnaires regarding the theory and procedures of each laboratory session allowed us to detect the main problems students had in the acquisition of the theoretical concepts before starting the practical activities. Additionally, the satisfaction of teachers and students with this methodology was also evaluated through surveys in the Moodle platform, showing consensus about the fact that the questionnaires are a valuable tool.

Journal of Electroanalytical Chemistry, 2020

A facile preparation of nitrogen doped graphene nanofibers (GNF) is required in order to promote ... more A facile preparation of nitrogen doped graphene nanofibers (GNF) is required in order to promote an easy scalable method for the production of batteries using this material as catalyst support. In this work, two simple oxygen pretreatments were developed in order to maximize the nitrogen amount on the structure of the carbon nanomaterial. In that sense, a mild-term oxidation with acid and a high oxidative procedure using potassium permanganate were developed. After that, the two oxidized fibers and the raw ones were doped using a hydrothermal method which use 2-chlorethyl amine as nitrogen donor. All the materials have been deeply studied by SEM, RAMAN, FTIR, CHNS, Zeta potential, XRD, N 2 adsorption-desorption and, TGA analysis. The characterization of the material showed that its structure after the treatments was more defective, significantly varying the surface area of the final material. After the hydrothermal treatment different amounts of N atoms (1.2-5.5%) were introduced in the structure depending on the oxidative treatment. The introduction of the nitrogen atoms increases the activity on oxygen reduction reaction (ORR) in almost all the cases, increasing further in the case of the GNF pretreated with acids which increase the electrochemical activity considerably.

Journal of Electroanalytical Chemistry, 2019

Abstract Two different approaches to simultaneously introduce nitrogen atoms within the graphene ... more Abstract Two different approaches to simultaneously introduce nitrogen atoms within the graphene framework and, reduce graphene oxide nanoplatelets (GO), have been explored in order to improve the electrocatalytic activity of the resulting materials. Thus, a facile hydrothermal method using 2-chloroethylamine under conditions at 180 °C and, another one, based in the formation of polypyrrole (PPy) on graphene oxide nanoplatelets by in situ polymerization of pyrrole monomer in the presence of GO, were compared through a deep characterization of the final materials by SEM, RAMAN, FTIR, XPS, Zeta potential, XRD and TGA analysis. Physico-chemical properties of the graphene-based materials were subsequently related with their electron transfer efficiency and electrocatalytic activity. The as prepared rGO prepared by the PPy method showed an N content quite superior (~6–8%) than the rGO prepared by the hydrothermal one (~1%) being an important part of their nitrogen state pyridinic type. The electrocatalytic results showed that GO exhibited higher specific capacitance than rGO materials due to its intrinsic higher porosity. However, the presence of N species seems to have a positive effect on the ORR activity, although the N incorporation through the PPy-rGO synthesis method seems to be the preferred one according for the complete ORR pathway.