Electronic‐Structure Calculations of Cation‐Ordered II‐III Layered Double Hydroxides: Origin of the Distortion of the Metal‐Coordination Symmetry

Abstract

Cation ordering brings down the crystal symmetry and introduces distortion into the coordination polyhedra around the divalent cations. In particular, edge sharing of the differently sized [M(OH)6] polyhedra causes a non‐uniform distension of the array of hydroxy ions. The question arises as to whether this distortion has its origin in the Jahn–Teller distortion of metal coordination or a 2D “Peierls”‐type distortion of the array of hydroxy ions. To address this question, DFT calculations were performed on the sulfate‐intercalated [Cu–Cr], [Zn–Cr], and [Zn–Al] layered double hydroxides (LDHs). An analysis of the density of states shows that the distortion of the Cu2+ coordination polyhedron is due to the Jahn–Teller effect, whereas the Zn2+ coordination polyhedron in [Zn–Al] LDH likely suffers a “Peierls”‐type distortion. In the [Zn–Cr] LDH, electronic‐structure calculations do not predict any distortion in the metal coordination, which is in agreement with experimental results that show only a slight departure from ideal symmetry.

Visible light photoreforming of greenhouse gases by nano Cu–Al LDH intercalated with urea-derived anions

“…37 The weakening of the (110) plane is due to the presence of transition metal (Cu 2+ ), that disrupts the octahedral cation coordination and, consequently, leads to poor long-range ordering (known as the Jahn–Teller distortion effect). 27,39 It was observed that the intensity of the (110) plan decreased as the urea content decreased (Fig. 1), reflecting the role of urea percentage on the cation ordering within the layered structure.…”

Effect of Anions on the Delithiation of [Li–Al] Layered Double Hydroxides: Thermodynamic Insights

“…Unlike II–III LDHs ,− where structural information for SO 4 -LDHs is well established, there are limited reports on I–III LDHs. In this work, the SO 4 -LDH ( d spacing 10.6 Å) exhibits turbostratic disorder, resulting in diminished hkl reflections, which yield little structural information.…”

Theoretical study of the mechanism for photocatalytic CO2 reduction to methanol over layered double hydroxides

“…In previous literature, the Jahn-Teller effect of Cu-based LDHs has been widely reported. 75 In general, the selectivity of CH 3 OH for photocatalytic CO 2 reduction over LDHs should be evaluated by considering both DG PDS for CO 2 reduction to CH 3 OH* and DG for the further reduction of CH 3 OH*.…”