Análisis del acoplamiento electrón-fonón en monogermanidos mediante la teoría del funcional de la densidad con escalamiento de espín

– José Andrés Nuñez Ávila – Instituto de Física “Ing. Luis Rivera Terrazas” (IFUAP), Benemérita Universidad Autónoma de Puebla (BUAP)

Abstract

Se presenta un estudio de la dinámica de red y el acoplamiento electrón-fonón de la solución sólida Mn1–yFeyGe (0 <= y <= 1) en la estructura no-centrosimétrica B20. Previamente se ha reportado que MnGe exhibe fases magnéticas de alto espín (  2 µB/Mn), bajo espín (1 µB/Mn) y no magnético en función de la presión, mientras que FeGe únicamente presenta fases de alto espín (1 µB/Mn) con anomalías fonónicas y no magnético. En este estudio se exploran la relación que existe entre las diferentes fases magnéticas en la solución sólida y el acoplamiento electrón-fonón. Para ello, se han realizado cálculos de primeros principios, mediante la teoría del funcional de la densidad (DFT), usando el método de pseudopotenciales con bases mezcladas (MBPP). En particular, se analiza la evolución del momento magnético en función de la concentración de Fe (y) en la solución sólida, así como su relación con las diferentes fases magnéticas encontradas en la solución. Se pone especial énfasis en las frecuencias y en el linewidth fonónico, con el fin de determinar la influencia del magnetismo en la dinámica de red. Debido a la importancia de la adecuada descripción del momento magnético, se examina y se contrasta el enfoque de escalamiento del espín (ssxc) en la energía de intercambio y correlación dentro de DFT, con el fin de determinar sus efectos en las propiedades de interés previamente mencionadas.

Modelado de primeros principios de las superficies de Fermi de los compuestos tipo Kagome Pt3X2(X=In y Tl)

– Samuel Flóres García – Universidad Nacional Autónoma de México

Abstract

Los compuestos Pt3In2 y Pt3Tl2 tiene fase hexagonal con grupo espacial P63/mmc en los cuales las especies de Pt forman monocapas con ordenamiento tipo Kagome. Esta disposición genera propiedades muy características en su estructura electrónica. Tales como bandas aplanadas, provocada por la localización de los electrones debido a este arreglo atómico. Se modeló la estructura electrónica por medio la teoría de la densidad del funcional obteniendo las densidades de estados, la estructura de bandas y la superficie de Fermi, para ambos compuestos. Además se comparó los resultados de este último por medio de las oscilaciones de la magnetización provocadas por el efecto de De Haas-van Alphen reportado en la literatura en la dirección [0001]. Igualmente se varió el ángulo del campo magnético y con ello hacer un barrido de toda la superficie de Fermi obteniendo las frecuencias para otras direcciones además de la [0001]. Por medio la estructura de bandas proyectadas se caracterizan cuáles orbitales y a qué especie pertenecen las bandas que contribuyen a la superficie de Fermi.

Agradecemos a los proyectos DGAPA-UNAM IG101124 y DGAPA-UNAM IA100624. Los cálculos se realizaron en el centro de súpercomputo UNAM proyecto LANCAD-UNAM-DGTIC-368, LNSBUAP proyecto 202201042N e THUBAT KAAL IPICYT proyecto TKII-JGSA001.

Title

– L.A. Alvarado-Leal – Universidad Autónoma de Nuevo León

Abstract

Este estudio investiga la influencia de los momentos magnéticos de los metales de transicieon en la adsorción y activación del oxígeno molecular (O2) en sistemas de catalizadores de un solo átomo soportados en grafeno dopado con nitrógeno, utilizando cálculos de teoría del funcional de la densidad. Demostramos que los metales con mayores momentos magnéticos, como Cr y Mn, exhiben una afinidad y estabilización mejoradas en la adsorción de O2. En contraste, los metales con momentos magnéticos bajos o nulos, como Ni y Cu, muestran una capacidad disminuida para adsorber O2 de manera efectiva. Nuestro análisis de las energías de adsorción, las profundidades del potencial de Morse y la fuerza de reacción subraya el papel crítico de los momentos magnéticos de los metales de transición en dictar el rendimiento catalítico y caracterizar la naturaleza del enlace químico entre el centro metálico y el oxígeno. Esto proporciona información valiosa para optimizar los catalizadores de un solo átomo en las reacciones de reducción de oxígeno y otras aplicaciones de conversión de energía.

Comparative DFT Study of functionalized graphene for energy storage applications

– Elizabeth Fernandez-García – Universidad Nacional Autónoma de México

Abstract

Understanding the interaction of metal oxides and carbon in nanocomposite electrode materials for supercapacitors is a task to achieve by combining the high electrical conductivity and specific surface area from carbon structural arrays and the high pseudocapacitance from metal oxides. This interaction can be obtained by incorporating functional groups on the carbon nanomaterial surface. In this study, we realized the structural optimization of NH₂, COOH, and OH functional groups over pristine graphene and graphene with single vacancy. Comparing models’ Density of States (DOS) with functional groups shows higher charge density concentration at the Fermi level over pristine graphene, resulting in improved charge transfer. This enhancement is associated with an increased charge-discharge capacity in electrode materials designed for supercapacitors. Integrated quantum capacitance calculation in -1V to 1V potential revealed higher charge accumulation in graphene with single vacancy simulated models, with the OH model presenting the highest quantum capacitance. Accumulated superficial charge in -1V to 1V potential reveals a higher capacity of graphene with a single vacancy OH model to store more charge in negative and positive potential, allowing it to operate as a cathode and anode electrode.

Disociación de Moléculas de Agua Usando Superficies de BiOX

– Gabriel Martinez Gutierrez – Universidad Nacional Autónoma de México

Abstract

Hydrogen generation is complex because it requires high energy; an example is electrolysis, which needs 2.456 eV/particle to dissociate it [1]. Different materials have been investigated to achieve water splitting. Bismuth oxyhalides (BiOX, X = Cl, Br, I) are constantly investigated due to their efficient catalytic properties, among them recently the material BiOI (2×1) has been studied, which by first-principles simulations proved to be stable [2]. It has vacancy-mediated channels that serve as catalytic points for water splitting. Using the BiOI (2×1) structure, it was possible to determine an energy barrier to dissociate water molecules, where a barrier of 0.106 eV. Two hydrogen atoms are displaced in the process, recreating a proton transfer effect—such an effect generates lower energy barriers than those required for electrolysis. 

Este trabajo es apoyado por DGAPA-UNAM projects IG101124 and IA100624. Calculations were performed in the Miztli supercomputer projects LANCAD-UNAM-DGTIC-368. JGS acknowledges LNS-BUAP project 202201042N and THUBAT KAAL IPICYT supercomputing center project TKII-JGSA001 for their computational resources. 

Fernández-Escamilla, H. N., et al. “Bismuth and oxygen vacancies induce (2× 1) reconstructions in bismuth oxyhalide (BiOX, X= Cl, Br, I)(0 0 1) surfaces.” Applied Surface Science 618 (2023): 156583.

Exploring the potential of h-Zn2GeO4 as an Li-host anode

– Gabriel Cosio – Centro de Investigación Científica y de Educación Superior de Ensenada

Abstract

The demand for eco-friendly and efficient energy sources in industrial, portable, and wearable applications has driven extensive research into electrochemical storage devices. Among these technologies, lithium-ion batteries emerge as highly promising due to their exceptional physicochemical and electrochemical properties. These batteries offer a lightweight design, high-energy density, and compact size, attributes directly influenced by the active materials within the electrodes and the redox reactions occurring during charge and discharge processes. To further enhance lithium-ion battery performance beyond conventional graphite-based anodes, there is ongoing exploration of advanced nanomaterials with specific chemical compositions and crystalline structures capable of facilitating reversible and rapid conversion and alloying reactions, thus enabling superior Li-ion storage capacity. In this context, our study focuses on employing h-Zn2GeO4 nanoparticles as a Li-ion host material. The synthesis of h-Zn2GeO4 in a willemite-like phase using the facile Pechini method was proposed, followed by a comprehensive investigation into its physicochemical and electrochemical properties for Li-ion battery applications. Experimental analyses were complemented by computational simulations using Density Functional Theory (DFT) and Ab Initio Molecular Dynamics (AIMD) to delve into atomic-scale interactions between Li ions and the h-Zn2GeO4 crystal structure.

This work was supported by: project CONACYT-SENER No. 274314; DGAPA-UNAM IA100624, IG101124 and IN101523; Supercomputing center DGCTIC-UNAM, Project No. LANCAD-UNAM-DGTIC-150, LANCAD-UNAM-DGTIC-368 and LANCAD-UNAM-DGTIC-422.

Charge-density asymmetry in MoSO and MoSeO nanotriangles increases their reactivity towards the hydrodesulfurization reaction

– Jair Othoniel Dominguez Godinez – Universidad Nacional Autónoma de México

Abstract

Transition metal dichalcogenides have garnered attention because of their unique physical properties. Janus monolayers with different chalcogen layers may increase their versatility and range of applications. Paez et al. 10.1038/s41598- 021-00287-6 demonstrated that charge-density asymmetry generates curvature in MoSeS nanotriangles and, consequently, an increase in their reactivity. Considering such effect, in this work, we engineered the MoS2 and MoSe2 nanotriangles to generate MoSO and MoSeO via selective oxidation of one side of the monolayer, ending up with thermodynamically stable Janus monolayers. After that, we designed MoSO and MoSeO nanotriangles and analyzed the curvature generated by the difference in electronegativity between S/Se and O. Also, we analyzed the reactivity increase due to the induced curvature and discussed their potential in the hydrodesulfurization reaction.

We thank DGAPA-UNAM projects IA100624, and IG101124 for partial financial support. Calculations were performed in the DGCTIC-UNAM Supercomputing Center projects LANCAD-UNAM-DGTIC 368 and 422, LNS and THUBAT KAAL IPICYT.

Ab initio study of the TaN/MgO interface

– Victor Quintanar-Zamora – Universidad Nacional Autónoma de México

Abstract

The present work addresses possible interface models between TaN and FCC MgO (001) using density functional theory (DFT) calculations. The epitaxial relation of TaN layers and MgO bulk is [001]TaN/[001]MgO. It has been reported that MgO substrates promote the growth of high-quality superconducting FCC TaN thin films with better results than Si substrates [1]. Therefore, firstprinciples calculations were performed to explore the TaN/MgO system in detail. Slabs were evaluated using the interface formation energy (IFE) formalism [2, 3] to assess its thermodynamic stability. Four stable and one unstable interface models were identified. In the most stable model, a TaO transition layer is formed at the boundary between TaN and MgO, resulting from oxygen scavenging by the Ta. Additionally, the electronic properties at the interface, such as density of states (DOS) and electron localization function (ELF), were calculated. The total DOS reveals a metallic nature, and the projected DOS shows that Ta-dyz and Ta-dxz degenerated orbitals are the main contributors to the states at the Fermi energy. Finally, the ELF indicates ionic-type bonding at the interface. Keywords: tantalum nitride, magnesium oxide, thermodynamic stability, DFT. 

This work was supported by DGAPA-UNAM IG101124, IG101623, IA100624, and IN101523 projects, as well as the CB_CONACYT A1-S-33492 grant. Calculations were performed in the DGCTIC-UNAM Supercomputing Center, Project No. LANCAD-UNAM-DGTIC-150, LANCADUNAM- DGTIC-368 and LANCAD-UNAM-DGTIC-422, and the THUBAT KAAL IPICYT supercomputing center. 

[1] Chaudhuri S. Chaudhuri, I. J. Maasilta, L. Chandernagor, M. Ging, and M. Lahtinen, “Fabrication of superconducting tantalum nitride thin films using infrared pulsed laser deposition,” Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, vol. 31, no. 6, p. 061502, Nov. 2013, doi: 10.1116/1.4812698. 

[2] J. Guerrero-Sánchez and N. Takeuchi, “Formation of ferromagnetic/ferrimagnetic epitaxial interfaces: Stability and magnetic properties,” Comput Mater Sci, vol. 144, pp. 294–303, Mar. 2018, doi: 10.1016/j.commatsci.2017.12.049. 

[3] K. Alam, R. Ponce-Pérez, K. Sun, A. Foley, N. Takeuchi, and A. R. Smith, “Study of the structure, structural transition, interface model, and magnetic moments of CrN grown on MgO(001) by molecular beam epitaxy,” Journal of Vacuum Science & Technology A, vol. 41, no. 5, Sep. 2023, doi: 10.1116/6.0002546.

Efectos del modelo agua en las propiedades comformacionales del receptor transmembranal GPR40

– Jorge Alberto Aguilar Pineda – Benemérita Universidad Autónoma de Puebla

Abstract

El receptor GPR40, también conocido como FFAR1, forma parte de la familia de receptores transmembranales GPCR. Actualmente este receptor es considerado una diana terapéutica en el tratamiento de la diabetes mellitus tipo 2 (DMT2), ya que su activación está relacionada a la mejora del control glucémico al estimular la secreción de insulina. Haciendo uso de herramientas computacionales, como son las simulaciones de dinámica molecular y análisis de trayectorias, en esta plática se hablará acerca de la importancia del modelo de agua utilizado como solvente en los sistemas GPR40-membrana. En este trabajo analizamos el efecto de cuatro modelos de agua explícita sobre la estructura e interacciones del receptor GPR40. Los modelos elegidos fueron dos de tipo rígido (SPC/E y TIP4P) y sus modelos mejorados flexibles (FBA/ε y TIP4P/εflex). Diversas técnicas in silico fueron empleadas para este propósito.

Nanohojas de BN impurificadas con átomos de B empleadas para la purificación de gas natural

– Diana Pozos Silva – Benemérita Universidad Autónoma de Puebla

Abstract

El Nitruro de Boro (BN) es un material con alto potencial para desarrollar nanoestructuras alotrópicas (nanohojas, nanotubos y fullerenos). Este tipo de estructuras son significativamente estudiadas producto de sus aplicaciones que van desde la creación de dispositivos electrónicos hasta medio de transporte de fármacos, incluso, se utilizan para la purificación del gas natural. En este trabajo se presentan cálculos de primeros principios, usando la teoría de los funcionales de la densidad (DFT) a nivel del gradiente generalizado (GGAHSEh1PBE) para analizar el efecto de adsorción de N2 sobre nanohojas de BN prístina y nanohojas de BN impurificadas con átomos de boro para determinar las propiedades electrónicas, químicas y estructurales. Los resultados obtenidos muestran que el comportamiento electrónico de los complejos B27N27H18-N2, B29N24H18-N2, B27N27H18-2N2,B29N24H18-2N2, B27N27H18-3N2 y B29N24H18-3N2 son de carácter semiconductor (gap 5.80 – 2.25 eV) de acuerdo con las diferentes orientaciones geométricas estudiadas. La energía de adsorción dependiendo de la concentración de N2 se mantiene conforme se van colocando un mayor número de moléculas de N2 sobre la nanohoja prístina (Ead = -0.05 – -0.09 eV), esto es indicativo de que las moléculas de N2 son físisorbidas por las dichas hojas de BN lo que implica que posiblemente las hojas de BN no son aptas para la remoción de N2 del gas natural. Sin embargo, cuando la nanohoja es impurificada por átomos de boro las N2 son químicamente adsorbidas (Ead = -1.25 a -1.49 eV), lo que indica que estos sistemas son aptos para la remoción del N2 del gas natural.

Estudio de Primeros Principios Aplicados a MOenes

– Santiago Triana Bejarano – Universidad Nacional Autónoma de México

Abstract

In recent years, the interest in the study of two-dimensional (2D) materials has grown exponentially because of their unique structural, electronic, and magnetic properties. In the search for new 2D materials, the family of MXenes has attracted the attention of researchers. MXenes are a family of materials made up of metal carbides and nitrides. These 2D materials have numerous physical properties that make them ideal for manufacturing energy storage materials, biomedical applications, and electronic devices. Analogous to this family, researchers have discovered MOenes, which are made up of a transition metal and oxygen. These materials are expected to exhibit novel energy storage properties like MXenes. In recent years, the existence of molybdenum structures within the MXenes group has been demonstrated theoretically. In this work, a first-principles study of two MoO2 structures (1T and 2H) was carried out. We studied the structural and electronic properties of the MoO2 2D system. According to the phononic band structure and electronic band structure, both MoO2 systems are stable and exhibit metallic behavior. Furthermore, the 2H monolayer is the most stable.

Exploring the Li, Na and K intercalation process in the functionalized Mo2V2C3T2 (T = O, F, OH) MXene: insight from first-principles calculations.

– Raul Santoy-Flores – Universidad Nacional Autónoma de México

Abstract

MXenes are excellent candidates to be employed as anode in Li-ion batteries due to their electrochemical properties, high electrical conductivity, and low energy barriers for ion diffusion. Recent studies have demonstrated that bi-metallic MXenes, like Ti2Ta2C3, exhibit superior electrochemical performance compared to their monometallic counterparts, offering potential for extended lifespan in energy storage systems. In this work, we investigated the role of the surface functionalization in the Li intercalation process, for this porpoise, we considered the presence of O, F, Cl and OH functional groups onto the surface. Besides, we investigated the activation energy to diffuse the Li, Na and K ions onto the surface and the theoretical gravimetric capacity. Our findings indicate that the oxidized phase of Mo2V2C3 performs exceptionally well as an anode in batteries, providing higher gravimetric capacity with Li-ion integration. These insights highlight the promise of bi-metallic MXenes in advancing cycling stability and energy efficiency in next-generation energy storage devices.

Obtention of nitrogen-doped graphene from different types of graphene oxide

– M. Amezcua-Navarro – Universidad Nacional Autónoma de México

Abstract

In this study, we archived nitrogen-doped graphene by applying a post-treatment synthesis method taking graphene oxide and melamine as precursors. Graphene oxide (GO) is synthesized by the modified Hummers method, which promotes the presence of epoxy, hydroxyl groups, and some other oxygen species. The samples were characterized by UV-vis, FTIR, Bohem titration and XPS to study their composition. Its structure was studied by XRD, optical microscopy, AFM and TEM. The results show the presence of the expected functional groups in a two-dimensional multilayer structure. Nitrogen-doped graphene was obtained by heating graphene oxide and melamine mixtures to 700 °C. Through experimental adjustments to the concentration of oxygen functional groups within graphene oxide, achieved by modifying key parameters such as the edge:area ratio of the starting materials and the temperature of the synthesis reaction, we were able to confirm that some oxygen functional groups improve the formation of a unique species of nitrogen. Using density functional theory calculations, we investigated the vibrational modes of graphene oxide, reduced graphene oxide, and nitrogen-doped graphene and corroborated them with experimental data. The mechanism to form graphitic nitrogen in nitrogen-doped graphene was also studied by adsorption of melamine onto graphene oxide, desorption of NH3, and its interaction with the oxygen functional group to form the graphitic nitrogen site. 

We thank, DGAPA-UNAM projects IN111223, IA100624, IN101523, and the CONACHYT PROJECTS Al-S-17539. Calculations were performed in the DGCTIC-UNAM project no. LANCAD-UNAM-DGTIC-422 and project no. LANCAD-UNAM-DGTIC-382. We also thank Dr. Lazaro Huerta from IIM-UNAM and Eduardo Murillo from CNyN-UNAM for assistance with some characterizations and AG&P and LVMM groupmates for fruitful discussions.

Understanding the role of carboxylic acid surfactants growth inhibition effect in the area selective atomic layer deposition: The case of ZnO growth on Cu and Cu2O

– L.E. López-González – Universidad Nacional Autónoma de México

Abstract

A recently explored fabrication approach is area selective deposition (ASD), whose main advantage is that it allows growth only at specific regions in a self-aligned manner1. Typically, the control of surface functional groups is the approach employed to modify the deposition chemistry2 by using self-assembled monolayers (SAMs). Modifying surface functional groups before the atomic layer deposition (ALD) process gives rise to the area-selective atomic layer deposition technique (AS-ALD) 3. Even though AS-ALD has great potential, it faces challenges that must be overcome, such as selectivity loss with increasing ALD cycles. In this context, the study of the adsorption of surfactants in surfaces and the effect that co-adsorbed ALD precursor molecules have on the surface–inhibitor molecule system is of interest to further understand the factors impacting selectivity loss in SAM AS-ALD. Here, we report a detailed adsorption process of acetic acid (AA) as a model of carboxylic acid self-assembled monolayers head group- on Cu and Cu2O (111) surfaces and the effect of diethyl zinc (DEZ) on its adsorption geometry on Cu2O (111) by using quantum chemical calculations. The most stable adsorption configurations were obtained considering electrostatic potential compatibility from the molecule and surface. Overall, the adsorption behavior revealed bidentate binding as the most stable configuration. Weak van der Waals interactions are key in AA adsorption on Cu (111), while in Cu2O (111), coordination and hydrogen bonds dominated the interaction. AA adsorption geometry on Cu2O revealed that DEZ has no significative impact on the monodentate and bidentate adsorption modes. These results highlight the significance of the different adsorption modes for achieving area-selective deposition using atomic layer deposition and soft removal SAM molecules.

References
1 M. Pasquali, S. De Gendt and S. Armini, Understanding the impact of Cu surface pre-treatment on Octadecanethiol-derived self-assembled monolayer as a mask for area-selective deposition, Appl Surf Sci, 2021, 540, 148307.
2 D. Bobb-Semple, L. Zeng, I. Cordova, D. S. Bergsman, D. Nordlund and S. F. Bent, Substrate-dependent study of chain orientation and order in alkylphosphonic acid self-assembled monolayers for ALD blocking, Langmuir, 2020, 36, 12849–12857.
3 F. S. Minaye Hashemi, B. R. Birchansky and S. F. Bent, Selective Deposition of Dielectrics: Limits and Advantages of Alkanethiol Blocking Agents on Metal–Dielectric Patterns, ACS Appl Mater Interfaces, 2016, 8, 33264–33272.

Understanding DFT+U: Analyzing the Density of States and Band Structure in MnSi2N4

– B. Pedroza Rojas – Universidad Autónoma del Estado de Hidalgo

Abstract

Layered two-dimensional magnetic materials have been used in recent years to design magneto-resistance electronic devices. These materials are often theoretically predicted before being obtained experimentally. An adequate and careful theoretical framework for this purpose is Density Functional Theory (DFT), which includes various pseudopotentials and substantial research backing it. However, a significant challenge arises when transition metals are involved. The unfilled d and f orbitals of these metals require semi-empirical considerations or hybrid pseudopotentials, which often do not accurately describe the electronic and magnetic properties in practice. Furthermore, the demand for durable and faster components can be met by 2D materials like the MA2Z4 family, a promising alternative. However, M can represent any transition metal, and many studies have been published without these semi-empirical treatments. In this context, we analyze the correction of 3d orbitals in MnSi2N4 using the Hubbard method according to Dudarev’s formulation. 

We thank to CONACYT (grant No. 432), to DGSCA-UNAM Supercomputer Center (project 3-2023) and to LANCAD Supercomputer Center (project 23-2023) for valuable computer resources used in this research.

Análisis computacional de propiedades de fármacos en el tratamiento de la diabetes

– Jesús Pérez Aguilar – Benemérita Universidad Autónoma de México

Abstract

La diabetes mellitus es la segunda enfermedad con mayor prevalencia en la población mexicana, afectando aproximadamente al 10.3% de la población, lo que equivale a 14.1 millones de personas. En la actualidad, se han desarrollado tratamientos con péptidos que inhiben la hormona Glucagón-1 (GLP-1) y aumentan la producción de insulina. Utilizando métodos computacionales como la Dinámica Molecular (DM), es posible investigar aspectos microscópicos que complementan los estudios experimentales y contribuyen al desarrollo de fármacos más específicos. En este trabajo se presenta un estudio detallado de estructuras de interés en el tratamiento de la diabetes. Para el análisis, se emplearon estructuras cristalográficas obtenidas del Protein Data Bank, de las cuales se aislaron los péptidos de interés: semaglutida, liraglutida, tirzepatida y exenatida. Durante las simulaciones de DM, el agua se incluyó explícitamente utilizando el modelo TIP4P, conocido por su alta capacidad predictiva de las propiedades del agua como solvente. Las estructuras solvatadas se neutralizaron con iones monovalentes y se añadió sal a una concentración de 0.154M para emular condiciones fisiológicas, manteniendo una temperatura de 309.65 K y una presión de 1 bar. Se generaron dos tipos de sistemas para el estudio. El primer sistema consiste en el fármaco disuelto en agua bajo condiciones fisiológicas. El segundo sistema incluye el fármaco en presencia de glucosa e insulina, también en condiciones fisiológicas. Estas simulaciones permiten una comprensión más profunda de la interacción entre los péptidos y su entorno, proporcionando información valiosa para el diseño de tratamientos más eficaces para la diabetes.

Computational study of the TiO2-surface LP gas detection mechanisms

– Jonathan E. Rodriguez Hueso – Universidad Nacional Autónoma de México

Abstract

Understanding and manipulating materials at the atomic scale has become a fundamental aspect of engineering the materials involved in high-performance devices. In the present work, we report the sensing behavior and structural properties of the titanium dioxide surface (TiO2) of the optimized structures and describe the structural and electronic properties of the interaction between the molecules that integrate the LP gas (butane, propane, and methanethiol) and the anatase TiO2 surface. The aim was to evaluate the feasibility of this material in a high-performance LP gas sensor device. Results demonstrate that the methanethiol of LP gas was the most reactive molecule to the TiO2 surface. In addition, the electrical properties calculated show the need to induce oxygen surface vacancies or a rearrangement of the (101) surface TiO2 anatase to make the interaction with methanethiol detectable. Our results are a step further in the design of LP gas sensing devices with modified TiO2 substrates.

DGAPA-UNAM IG101124, IA100624, IN101523, IG101623, and Conhacyt grants A1-S-9070 and A1-S-26789 of the Call of Proposals for Basic Scientific Research 2017–2018 for partial financial support. Calculations were performed in the DGCTIC-UNAM Supercomputing Center, projects LANCAD-UNAM-DGTIC-368, LANCAD-UNAM-DGTIC-051, LANCAD-UNAM-DGTIC-390, and LANCAD-UNAM-DGTIC-422 We thank Aldo Rodriguez-Guerrero; Rodrigo Ponce; J. I. Paez Ornelas and nanomaterials modeling department for technical support.

El uso de materiales topológicos en la reacción de evolución de Hidrógeno

– Jonathan E. Rodriguez Hueso – Universidad Nacional Autónoma de México

Abstract

La reacción de evolución de hidrógeno (HER, por sus siglas en inglés) es un proceso químico en el cual se produce gas hidrógeno (H2) a partir de protones (H+) y electrones (e-), típicamente en presencia de un catalizador [1]. Esta reacción tiene varias aplicaciones, y una de las más notables es la batería de hidrógeno, que permite un medio de almacenamiento de energía limpia que solo deja agua como producto residual. El problema es que el catalizador más eficiente para esta reacción es el platino, el cual es aún menos abundante que el oro. Se están haciendo esfuerzos para encontrar una alternativa más económica para un catalizador para HER, y se ha encontrado un lugar prometedor en los materiales cuánticos topológicos (TQM), aquí presentaremos los resultados de la investigación bibliográfica sobre dicho tema. Estos materiales tienen propiedades eléctricas muy únicas que pueden explicarse estudiando su estructura electrónica utilizando conceptos matemáticos que pertenecen a la rama de la Topología. Exhiben estados superficiales que son robustos frente a perturbaciones e impurezas, así como una alta movilidad de carga, propiedades que les dan el potencial de tener una alta actividad catalítica para HER, similar o incluso mayor que la del Pt, proporcionando un catalizador efectivo sin la necesidad de metales preciosos.

Referencias
1. Yang, Q. (2021) The rise of topologically non-trivial materials for hydrogen
evolution electrocatalysis. Max-Planck-Institu für Chemische Physik fester
Stoffe.
2. Xie, R., Weng, H., Chai, G. (2022). Progress, Advantages and Challenges
of Topological Material Catalysts. Perspective. Small Science