Oxidation of Cyclohexanol on Phosphotungstic Acid Anion Intercalated Layered Double Hydroxides With Aqueous H2o2 as Oxidant

Abstract

The layered double hydroxides (LDH) of Mg 2 AlNi and Mg 3 Al pillared by Keggin-type phosphotungstic acid anion (POM), i.e. Mg 2 AlNi-POM LDH and Mg 3 Al-POM LDH were synthesized by an ion-exchange method. The synthesized POM intercalated LDH compounds were characterized using various techniques such as FTIR, XRD, TGA and BET. The observed results show that the obtained catalysts retain the layer structure of LDH. Compared with the binary Mg 3 Al-POM LDH, the ternary Mg 2 AlNi-POM LDH catalyst indicated a higher thermal and chemical stability. The catalytic activity of the resulting LDH-POM was also assessed in the green oxidation of cyclohexanol with aqueous H 2 O 2 as an oxidant. The Mg 2 AlNi-POM LDH showed a much higher conversion and selectivity for cyclohexanone than the corresponding Mg 3 Al-POM LDH catalyst.

Polyoxometalate-Intercalated Tremella-Like CoNi-LDH Nanocomposites for Electrocatalytic Nitrite–Ammonia Conversion

“…It is noteworthy that the position of the (003) diffraction peak moves from the original 10.79° of CoNi-LDH to a lower 2θ diffraction angle of 6.06°. According to Bragg’s equation (2 d sin θ = n λ, where d represents the layer spacing, n = 1, λ = 0.15406 nm), , the layer spacings of pristine NO 3 – intercalated CoNi-LDH and P 8 W 48 /CoNi-LDH can be calculated as 0.82 and 1.46 nm, respectively. The gallery height value of 0.98 nm can be obtained by subtracting the thickness of the host layer (0.48 nm) from the d -spacing value of P 8 W 48 /CoNi-LDH, which is almost equivalent to the theoretical diameter of the short axis of P 8 W 48 determined from the crystallographic data (1.0 nm) .…”

“…The lattice fringes with the interplanar distance of 2.56 Å corresponds to the (012) facet of P 8 W 48 /CoNi-LDH can be observed in the high-resolution (HR) TEM image (Figure 1g). 52 The scanning transmission electron microscopy (STEM) mapping results exhibited in Figure 1h 47,53 the layer spacings of pristine NO 3 − intercalated CoNi-LDH and P 8 W 48 /CoNi-LDH can be calculated as 0.82 and 1.46 nm, respectively. The gallery height value of 0.98 nm can be obtained by subtracting the thickness of the host layer (0.48 nm) from the d-spacing value of P 8 W 48 /CoNi-LDH, which is almost equivalent to the theoretical diameter of the short axis of P 8 W 48 determined from the crystallographic data (1.0 nm).…”