Calculation of the morphology of silica sodalite

Loades, Stephen D.; Carr, Stuart W.; Gay, David H.; Rohl, Andrew

doi:10.1039/c39940001369

Cited by 26 publications

(13 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, limited attention has been paid to the structure and defect redox chemistry of the La 2 NiO 4 surfaces, due in part to the difficulties concerned with obtaining high-quality experimental data for mixed-metal oxide surfaces at the atomic level. It is now well established that computer modelling techniques 20,21 have made widespread contributions to the study of defect, ion transport and surface properties of a wide variety of oxide compounds, including catalysts [22][23][24][25] and perovskite-type conductors. 26,27 Our previous simulation studies of La 2 NiO 4 have concentrated on bulk properties.…”

Section: Introductionmentioning

confidence: 99%

Surface structures and defect properties of pure and doped La2NiO4

et al. 2001

View full text Add to dashboard Cite

Computer modelling techniques are used to investigate the surface properties and defect chemistry of the La 2 NiO 4 material. Relaxed surface structures and energies are calculated for the low index planes which are used to predict the equilibrium crystal morphology. The {111} surface is calculated to dominate in the absence of impurities, water or surface irregularities, with significant contributions from the {100} and {001} surfaces. Isovalent doping of the Ni site by Fe and Cu is found to affect the crystal morphology by increasing the expression of the {001} surface, although Fe doping is predicted to create the {011} face which is not present in the undoped crystal. The Sr dopant at the La site is calculated to be the most soluble of the alkaline earth metals, in accord with observation. Charge compensation is predicted to occur via the formation of Ni(III), which is consistent with bulk calculations and catalytic models in which Ni(III) species are correlated to the observed catalytic activity.

show abstract

Section: Introductionmentioning

confidence: 99%

Surface structures and defect properties of pure and doped La2NiO4

et al. 2001

View full text Add to dashboard Cite

show abstract

“…5.5.1.5.3 Surface Structure of Framework Materials, and their Properties The earliest surface simulation studies in zeolite science were conducted during the mid-1990s by Loades et al [180], and separately by Baram and Parker [223], who both studied the surface structure of all-silica Sodalite. 5.5.1.5.3 Surface Structure of Framework Materials, and their Properties The earliest surface simulation studies in zeolite science were conducted during the mid-1990s by Loades et al [180], and separately by Baram and Parker [223], who both studied the surface structure of all-silica Sodalite.…”

Section: Surface Modeling Techniquesmentioning

confidence: 99%

Modeling of Structures and Reactivity of Solid Catalysts

Catlow

Bell

Slater

et al. 2008

Handbook of Heterogeneous Catalysis

View full text Add to dashboard Cite

IntroductionComputer modeling tools are now well established in modeling catalytic systems and processes. In particular, they allow us to model catalyst and active-site structures, as well as reaction intermediates and mechanisms. This chapter focuses on their application to inorganic catalytic materials, in particular microporous materials and metal oxides. Especially, modeling of the structure at the atomic level of catalytic materials and of their surfaces is emphasized. The challenging question of unraveling reaction mechanisms is also addressed. * Corresponding author.Basic methodological aspects and earlier applications are summarized in the following section, after which reviews are presented of the main contemporary techniques for structure modeling and prediction. A summary of techniques and applications for the modeling of surface structures and properties is also provided, with special emphasis on microporous materials, in view of their importance and wide-ranging application in catalysis and other technologies. Metal oxides and other inorganic materials are also considered, and techniques and approaches applicable to the general modeling of structures and surfaces and reactions, both in and on solids, are described. Solid-State Modeling Techniques: Energy Calculations BasicsComputer modeling at the atomic and molecular level uses a wide range of methods, including those based on interatomic potentials (or forcefields) and quantum mechanical techniques. Use of the latter is essential when considering processes (such as reaction mechanisms) that depend on bond-breaking and making; they are considered later in this section and in Chapter 5.1.2. Our initial focus is, however, on modeling the structural properties of solids and their surfaces, where forcefield methods have been widely used.The complex and fascinating range of crystal structures adopted by inorganic materials has provided a powerful incentive for the development of effective tools for modeling and, more ambitiously, predicting their structures. These methods may be used to assist structure determination, to classify existing structures, and to explore and predict new topologies and corresponding structures. The field has a long history, with one of the most fruitful areas of application having been in zeolite science, where the early studies of Smith and coworkers [1, 2] (and vide infra) pioneered the application of principles based on network topologies. Techniques based on lattice energy minimization were developed and refined during the 1980s and 1990s and applied to many classes of solid; these approaches have subsequently been combined with simulated annealing and genetic algorithm techniques in order to provide powerful structure prediction tools as discussed later in this chapter. Lattice energy calculations have also been used to assess the viability of new hypothetical structures which have been generated by systematic topological enumeration methods; while new structures have additionally been generated by applications of simulate...

show abstract

“…Previous work on morphology studies has involved studying both organic1–6 and inorganic systems 7–12. A recent study of the polymorphs of paracetamol13 has combined polymorph prediction, morphology prediction, and calculation of mechanical properties.…”

Section: Introductionmentioning

confidence: 99%