Models for the estimation of thermodynamic properties of layered double hydroxides: application to the study of their anion exchange characteristics

Abstract

Several models for the estimation of thermodynamic properties of layered double hydroxides (LDHs) are presented. The predicted thermodynamic quantities calculated by the proposed models agree with experimental thermodynamic data. A thermodynamic study of the anion exchange process on LDHs is also made using the described models. Tables for the prediction of monovalent anion exchange selectivities on LDHs are provided. Reasonable agreement is found between the predicted and the experimental monovalent anion exchange selectivities

Fullerene as a Photoelectron Transfer Promoter Enabling Stable TiO2‐Protected Sb2Se3 Photocathodes for Photo‐Electrochemical Water Splitting

“…It should be noted that this accumulated electron‐induced reduction occurs only at the surface of TiO 2 , where the latter meets the acidic electrolyte. The Φ red of TiO 2 based on Equation is −0.6 V versus RHE, calculated from the change in its Gibbs free energy, which is located above the CBM of TiO 2 (−0.2 V vs RHE). A Φ red located higher than the CBM indicates that TiO 2 is inherently stable under PEC conditions because the energy of a photoelectron in the CBM is insufficient to drive the self‐reduction of TiO 2 .…”

Characterization of hyperalkaline fluids produced by low‐temperature serpentinization of mantle peridotites in the Oman and Ligurian ophiolites

“…[64] Lastly, Anraku et al [2010] report the formation of hydrotalcite, Mg 6 Al 2 (CO 3 )(OH) 16 4(H 2 O), a mineral of the layered double hydroxides (LDH) family [Bravo-Suarez et al, 2004;Goh et al, 2008] in the mixing zone between the wadi waters and the high-pH fluids. Although occurring in trace quantities [Anraku et al, 2010], hydrotalcite may indeed control the Mg concentration of the waters, but also on their carbonate content.…”

Halide Exchange on Mg(II)–Al(III) Layered Double Hydroxides: Exploring Affinities and Electrostatic Predictive Models

“…This behavior indicates that the LDH's Mg(II) to Al(III) ratio, which governs the charge density, proportionally affects the free energy of a given anionic exchange process; certain general thermochemical stability models based on mechanical mixtures of parent single hydroxides suggest this trend. 47 Electrostatic Models To Predict Halide Exchange Reaction Free Energy. In the following, a first microscopic attempt to understand the observed results as well as the inferred ones will be analyzed in terms of the simplest ionic exchange model, originally developed by Barrer and Townsend, 48,49 for cationic exchange reactions developed by clays (see detailed equations in the Supporting Information).…”