Using first-principles calculations, we systematically study the adsorption behaviors of molecular CO on the Be (0001) surface. By calculating the potential energy surfaces, we find that CO molecularly adsorbs on the Be surface with small energy barriers. The most stable adsorption state is found to be the one at the surface fcc hollow site, and the one at the surface top site is the adsorption state that has the smallest energy barrier. Based on electronic structure analysis, we further reveal that during the molecular adsorption, the $5σ$ bonding and $2π$ antibonding orbitals of CO hybridize with $s$ and $p_z$ electronic states of Be, causing electrons to transfer from CO to Be.
The relationship between activated H2 bond length and adsorption distance on MXenes identified with graph neural network and resonating valence bond theory
Evaluating Blended Refrigerants for Thermochemical Energy Storage and Circular Refrigerant Recovery using Activated Carbons
Eindhoven University of Technology（埃因霍温理工大学）；Eindhoven Institute for Renewable Energy Systems (EIRES), Eindhoven University of Technology（埃因霍温理工大学可再生能源系统研究所）
Influence of Ultramicroporosity and Surface Chemistry on Dynamic CO2 Capture in Activated Carbons
Eindhoven University of Technology（埃因霍温理工大学）；IMDEA Energy Institute（IMDEA能源研究所）；Instituto de Catálisis y Petroleoquímica (ICP), CSIC（西班牙国家研究委员会催化与石油化工研究所）
We perform first-principles calculations of electronic and dielectric properties of bismuthene functionalized with small ligands using first-principle calculations. We show that all functionalized structures have topological insulating (TI) behavior with a sizeable gap by calculating the Z$_2$ topological invariant. Furthermore the adsorption of all groups induce a quasi-planar structure to the initially pristine bismuthene structure. Finally we show that the dielectric properties show a large anisotropy with two main in plane absorption peaks.
The adsorption kinetics of CO on PdAu bimetallic clusters, containing 140 $\pm$ 12 atoms and a composition varying between 0% and 55% of Pd atoms, is investigated by a pulsed molecular beam method (MBRS). The clusters are grown on a nanostructured ultrathin film of alumina on Ni3Al (111) playing the role of a template which gives a hexagonal array of bimetallic clusters having a sharp size distribution and a uniform composition. The surface concentration calculated, assuming segregation of gold to the surface, varies between 0 and 90% of Au atoms on the surface. From the adsorption-desorption …
Density functional theory $(DFT)$ studies show that doping of $3d TM$ atoms into $Mg_4^{0,+} (TMMg_3^{0,+})$ can alter the endothermic nature of molecular hydrogen adsorption on bare $Mg_4^{0,+}$. $H_2$ adsorption on $TMMg_3^{0,+}$ clusters depends on the $TM(3d)$ orbital contribution to the frontier molecular orbitals of the clusters. In $H_2TMMg_3^{0,+}$ complexes, $H_2$ is adsorbed through donation and back donation of electronic charges with $TMMg_3^{0,+}$ clusters. $H_2$ binding energy is the maximum for $NiMg_3$ (-0.76 eV) and $FeMg_3^+$ (-0.48 eV) among the neutral and cationic $TMMg_3$…
Understanding surface reactivity is crucial in many fields, going from heterogeneous catalysis to materials oxidation and corrosion. In order to decipher the surface reactions of ZrB2 exposed to the harsh environment of aerospace components, the chemical activity of both Zr- and B-surfaces is predicted and compared by using density functional theory and nudged elastic band methods. In particular the adsorption, dissociation and diffusion of O2, CO and H2O are extensively examined through the calculation of surface adsorption energies and reaction pathways. We find the dissociative adsorption o…
Only recently, the activation of oxygen molecules on clean defect-free transition metal oxide surfaces has been reported, for example on the CaO-terminated surface of the Ruddelsden-Popper perovskite \crosurf. In this work we show that oxygen molecules adsorb as an activated superoxo species on a clean SrO-terminated surface of \srosurf. At all coverages, the electrons activating the molecule originate from the subsurface RuO$_2$ layer. At low coverages, the presence of a Ca dopant in the terminating SrO layer slightly increases the adsorption energy. At high coverage, DFT predicts a flat pote…
We report the growth of the intrinsic magnetic topological system MnTe(Bi2Te3)n by molecular beam epitaxy. By mapping the temperature and the Bi:Mn flux ratio, it is shown that there is a narrow growth window for the n=1 phase MnBi2Te4 with 2.0<Bi:Mn<2.6 at 225 °C. Here the films are stoichiometric and excess Bi and Te is not incorporated. At higher flux ratios (Bi:Mn>4.5) it is found that the n = 2 MnBi4Te7 phase is stabilized. Transport measurements indicate that the MnBi2Te4 and MnBi4Te7 undergo magnetic transitions around 25 K, and 10 K, respectively, consistent with antiferromagnetic phas…
Surface adsorption is one of the fundamental processes in numerous fields, including catalysis, environment, energy and medicine. The development of an adsorption model which provides an effective prediction of binding energy in minutes has been a long term goal in surface and interface science. The solution has been elusive as identifying the intrinsic determinants of the adsorption energy for various compositions, structures and environments is non-trivial. We introduce a new and flexible model for predicting adsorption energies to metal substrates. The model is based on easily computed, int…
Molecular Adsorption of H2O on TiO2 and TiO2:Y Surfaces
S.U. Umarov Physical-Technical Institute of the National Academy of Science of Tajikistan（塔吉克斯坦国家科学院S.U.乌马尔物理技术研究所）；Osimi Tajik Technical University（塔吉克技术大学奥西米分校）；Joint Institute for Nuclear Research（苏联联合核子研究所）；Dubna State University（杜布纳国立大学）；Nanotechcenter LLC（纳米技术中心有限责任公司）；Lusófona University, IDEGI（卢索丰大学IDEGI）
The adsorption and diffusion of F2 molecules on pristine graphene have been studied using first-principles calculations. For the diffusion of F2 from molecular state in gas phase to the dissociative adsorption state on graphene surface, a kinetic barrier is identified, which explains the inertness of graphene in molecular F2 at room temperature, and its reactivity with F2 at higher temperatures. Studies on the diffusion of F2 molecules on graphene surface determine the energy barriers along the optimal diffusion pathways, which help to understand the high stability of fluorographene.
The structure of the double-layer formed at the surface of carbon electrodes is governed by the interactions between the electrode and the electrolyte species. However, carbon is notoriously difficult to simulate accurately, even with well-established methods such as electronic Density Functional Theory and Molecular Dynamics. Here we focus on the important case of a lithium ion in contact with the surface of graphite, and we perform a series of reference Quantum Monte Carlo calculations that allow us to benchmark various electronic Density Functional Theory functionals. We then fit an accurat…
We investigate the recovery of structures from large-area, low dose exposures that distribute the dose over many identical copies of an object. The reconstruction is done via a maximum likelihood approach that does neither require to identify nor align the individual particles. We also simulate small molecular adsorbates on graphene and demonstrate the retrieval of images with atomic resolution from \add{large area and} extremely low dose raw data. Doses as low as 5 $e^{-}/$Å$^{2}$ are sufficient if all symmetries (translations, rotations and mirrors) of the supporting membrane are exploited t…
Microporous organosilicas assembled from polysilsesquioxane (POSS) building blocks are promising materials that are yet to be explored in-depth. Here, we investigate the processing and molecular structure of bispropylurea bridged POSS (POSS-urea), synthesised through the acidic condensation of 1,3-bis(3-(triethoxysilyl)propyl)urea (BTPU). Experimentally, we show that POSS-urea has excellent functionality for molecular recognition toward acetonitrile with an adsorption level of 74 mmol/g, which compares favourably to MOFs and zeolites, with applications in volatile organic compounds (VOC). The …
Molecular adsorption at the surface of a 2D material poses numerous questions regarding the modification to the band structure and interfacial states, which of course deserve full attention. In line with this, first-principle density functional theory is employed on the graphene/ammonia system. We identify the effects on the band structure due to strain, charge transfer and presence of molecular orbitals (MOs) of NH3 for six adsorption configurations. The induced strain upon ammonia-adsorption opens the bandgap (Eg) of graphene due to the breaking of translational symmetry and shifts the equil…
We investigate the adsorption and diffusion behaviors of CO2, CH4, and N2 in interfacial systems composed of a polymer of intrinsic microporosity (PIM-1) and amorphous silica using grand canonical Monte Carlo (GCMC) and molecular dynamics (MD) simulations. We build model systems of mixed matrix membranes (MMMs) with PIM-1 chains sandwiched between silica surfaces. Gas adsorption analysis using GCMC simulations shows that gas molecules are preferentially adsorbed in microcavities distributed near silica surfaces, resulting in an increase in the solubility coefficients of CO2, CH4, and N2 compar…
MAD-SURF: a machine learning interatomic potential for molecular adsorption on coinage metal surfaces
Universidad Autónoma de Madrid（马德里自治大学）；Aalto University（阿尔托大学）；Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid（马德里自治大学凝聚态物理中心（IFIMAC））；Nano Life Science Institute (WPI-NanoLSI), Kanazawa University（金泽大学纳米生命科学研究院（WPI-NanoLSI））
The role of catalyst support and regioselectivity of molecular adsorption on a metal oxide surface is investigated for the NO reduction on a Cu/γ-alumina heterogeneous catalyst. For the solid surface, computational models of the γ-alumina surface are constructed based on the Step-by-Step Hydrogen Termination (SSHT) approach. Dangling bonds, which appear by cutting the crystal structure of a model, are terminated stepwise with H atoms until the model has an appropriate energy gap. The obtained SSHT models exhibit the realistic infrared (IR) and ultraviolet-visible (UV/Vis) spectra. Vibronic cou…
The large number of possible structures of metal-organic frameworks (MOFs) and their limitless potential applications has motivated molecular modelers and researchers to develop methods and models to efficiently assess MOF performance. Some of the techniques include large-scale high-throughput molecular simulations and machine learning models. Despite those advances, the number of possible materials and the potential conditions that could be used still pose a formidable challenge for model development requiring large data sets. Therefore, there is a clear need for algorithms that can efficient…
pH-Responsive Glyphosate Adsorption on Hydroxylated Carbon Nanotubes: From Electronic Structure to Molecular Dynamics
Universidade Federal de Alfenas - UNIFAL-MG（阿尔芬纳斯联邦大学）；Instituto de Ciências Exatas - ICEx（理学院）；Laboratório de Modelagem Computacional - La Model（计算建模实验室）；Institute of Science and Tecnology - ICT（科学技术研究所）
Organic adlayers on inorganic substrates often contain adatoms, which can be incorporated within the adsorbed molecular species, forming two-dimensional metal-organic frameworks at the substrate surface. The interplay between native adatoms and adsorbed molecules significantly changes various adlayer properties such as the adsorption geometry, the bond strength between the substrate and the adsorbed species, or the work function at the interface. Here we use dispersion-corrected density functional theory to gain insight into the energetics that drive the incorporation of native adatoms within …
Halogenated aromatic molecules assemble on surfaces forming both hydrogen and halogen bonds. Even though these systems have been intensively studied on flat metal surfaces, high-index vicinal surfaces remain challenging, as they may induce complex adsorbate structures. The adsorption of 2,6-dibromoanthraquinone (2,6-DBAQ) on flat and stepped gold surfaces is studied by means of van der Waals corrected density functional theory. Equilibrium geometries and corresponding adsorption energies are systematically investigated for various different adsorption configurations.~It is shown that bridge si…
