Home Physical Sciences DFT+U investigation of the catalytic properties of ferruginous clay
Article
Licensed
Unlicensed Requires Authentication

DFT+U investigation of the catalytic properties of ferruginous clay

  • Dawn L. Geatches EMAIL logo , Stewart J. Clark and Hugh C. Greenwell
Published/Copyright: March 7, 2015
Become an author with De Gruyter Brill

Abstract

The formation of fossil oil within clay minerals i.e., mineral-catalyzed decarboxylation, is a mechanism awaiting a thorough chemical explanation. To contribute to such an explanation, the study presented here investigates this mechanism at the level of first-principles, electronic structure computations, employing density functional theory (DFT plus Hubbard-U), planewaves, pseudopotentials, and periodic cells of two types of ferruginous clay minerals, specifically two types of nontronite [Fe2 (Si,Al)4O10(OH)2]. The formation of the fossil oil is modeled as a decarboxylation pathway, converting the fatty acid propionic acid, C2H5COOH to an alkane, C2H6 and the intermediate stages along this conversion pathway are represented by five configurations of interlayer species within the clay minerals. In this study, we test both the effect of the presence of iron on the theoretical stages of decarboxylation, together with the effect of two different density functionals: with and without strong correlations of the d-orbital electrons of iron. We have found that inclusion of the d-orbital electron correlations in the guise of a Hubbard parameter results in the introduction of three new intermediate configurations (one of which is potentially a new transition state), alters the location of the occupied Fermi level orbitals, and changes the band gaps of the clay mineral/interlayer species composites, all of which serves to inform the chemical interpretation of mineral-catalyzed decarboxylation.

Received: 2012-4-22
Accepted: 2012-8-15
Published Online: 2015-3-7
Published in Print: 2013-1-1

© 2015 by Walter de Gruyter Berlin/Boston

Articles in the same Issue

  1. H/D isotope effects in brucite at low temperatures
  2. Coupled H and Nb, Cr, and V trace element behavior in synthetic rutile at 600 °C, 400 MPa and possible geological application
  3. Dissolution-reprecipitation vs. solid-state diffusion: Mechanism of mineral transformations in sylvanite, (AuAg)2Te4, under hydrothermal conditions
  4. Compression and structure of brucite to 31 GPa from synchrotron X-ray diffraction and infrared spectroscopy studies
  5. Full analysis of feldspar texture and crystal structure by combining X-ray and electron techniques
  6. Correlating planar microstructures in shocked zircon from the Vredefort Dome at multiple scales: Crystallographic modeling, external and internal imaging, and EBSD structural analysis
  7. A spectroscopic and carbon-isotope study of mixed-habit diamonds: Impurity characteristics and growth environment
  8. Thermal infrared and Raman microspectroscopy of moganite-bearing rocks
  9. Mineralogical characterization and formation of Fe-Si oxyhydroxide deposits from modern seafloor hydrothermal vents
  10. Cathodoluminescence properties of quartz eyes from porphyry-type deposits: Implications for the origin of quartz
  11. Microbeam X-ray analysis of Ce3+/Ce4+ in Ti-rich minerals: A case study with titanite (sphene) with implications for multivalent trace element substitution in minerals
  12. Aluminum ordering and clustering in Al-rich synthetic phlogopite: The influence of fluorine investigated by {19F/1H} 29Si CPMAS NMR spectroscopy
  13. DFT+U investigation of the catalytic properties of ferruginous clay
  14. A thermodynamic model for silica and aluminum in alkaline solutions with high ionic strength at elevated temperatures up to 100 °C: Applications to zeolites
  15. Nanopores in hematite (α-Fe2O3) nanocrystals observed by electron tomography
  16. Berthierine-like mineral formation and stability during the interaction of kaolinite with metallic iron at 90 °C under anoxic and oxic conditions
  17. An X-ray diffraction study of the pressure-induced hydration in cordierite at 4–5 GPa
  18. Natural occurrence of keatite precipitates in UHP clinopyroxene from the Kokchetav Massif: A TEM investigation
  19. High-pressure Raman spectroscopy, vibrational mode calculation, and heat capacity calculation of calcium ferrite-type MgAl2O4 and CaAl2O4
  20. First-principles study on the high-pressure phase transition and elasticity of KAlSi3O8 hollandite
  21. Zircon growth and recrystallization during progressive metamorphism, Barrovian zones, Scotland
  22. Saltonseaite, K3NaMn2+Cl6, the Mn analogue of rinneite from the Salton Sea, California
  23. Rongibbsite, Pb2(Si4Al)O11(OH), a new zeolitic aluminosilicate mineral with an interrupted framework from Maricopa County, Arizona, U.S.A.
  24. Quadratite, AgCdAsS3: Chemical composition, crystal structure, and OD character
  25. Crystal chemistry of layered Pb oxychloride minerals with PbO-related structures: Part I. Crystal structure of hereroite, [Pb32O20(O,⃞)](AsO4)2[(Si,As,V,Mo)O4]2Cl10
  26. Crystal chemistry of layered Pb oxychloride minerals with PbO-related structures: Part II. Crystal structure of vladkrivovichevite, [Pb32O18][Pb4Mn2O]Cl14(BO3)8·2H2O
  27. Amorphous materials: Properties, structure, and durability: Acceleration and inhibition effects of phosphate on phase transformation of amorphous calcium carbonate into vaterite
  28. Letter: Implications of equilibrium and disequilibrium among crystal phases in the Bishop Tuff
  29. Letter: Actinides in Geology, Energy, and the Environment: Chemistry and radiation effects of davidite
Downloaded on 13.2.2026 from https://www.degruyterbrill.com/document/doi/10.2138/am.2013.4204/html
Scroll to top button