Topotactic preparation of copper-cobalt oxide spinels by thermal decomposition of double-layered oxide hydroxide nitrate mixed crystals

DFT‐Based Simulation and Experimental Validation of the Topotactic Transformation of MgAl Layered Double Hydroxides

“…[12,13] The topotactic transformation of LDHs occurring upon the calcination under reducing conditions plays ak ey role in the fabrication of supported metal nanocatalysts with specific surfaces tructure and high dispersion. [13][14][15][16] Although much effort has been focusedo nt he preparation of nanocatalysts through the LDH precursor approach,s tructurale volution (including metal migration, the dehydration process of host layers,and the formation mechanism of metal oxides) during the LDH thermald ecomposition process is still not revealed clearly, [17][18][19][20] which limits the furtherdevelopment of LDH-based high-performance nanocatalysts. Therefore, ad etailed understanding of the topotactic transformation of LDHs is essential andr emains achallenging goal.…”

“…Several experimental studies on topotactic structural evolution in the thermald ecompositiono fL DHs have been performed; [16,21] these show that the decomposition process involvesf our main stages:the first step corresponds to the evaporation of weakly adsorbed surface and interlayer water,t he second one is due to the removal of intercalated anions, the third one involves the dehydroxylation and collapse of the layered structure, and the final step is usuallya ttributed to the formation of mixed-metal oxides( MMOs). [19,22,23] Petrov and Markov proposed "similar crystallographic correlations"b etween LDHs and the as-obtained metal oxidest od efine the topotactic decomposition of LDHs, and believed thatm etal distribution in the crystal lattice was ak ey issue in understanding the topotactic process.…”

“…[19,22,23] Petrov and Markov proposed "similar crystallographic correlations"b etween LDHs and the as-obtained metal oxidest od efine the topotactic decomposition of LDHs, and believed thatm etal distribution in the crystal lattice was ak ey issue in understanding the topotactic process. [16] Recently,s ome researchers deduced that the stacking of cationss howed the largestd ensity (compared with other facets) on the (00l)p lane of LDH;t herefore, during the topotactic decomposition of LDHs, oxide nucleationo nt he (00l)f acet gave the lowest nucleation energy and led to the formation of the (111)-oriented metal oxides. [21] The thermal topotactic transformation mechanism of MgAl layered double hydroxides (LDHs) is investigated by ac ombined theoreticala nd experimental study.T hermogravimetric differential thermala nalysis( TG-DTA) results reveal that the LDH phase undergoes four key endothermic events at 230, 330, 450, and 800 8C.…”

Synthesis, characterisation and sustained release properties of layered zinc hydroxide intercalated with amoxicillin trihydrate

“…[6] Different methods are there for the synthesis of layered zinc hydroxide; hydrolysis of salts and oxides, [7] urea hydrolysis, [8] precipitation with alkaline solutions, [9,10] solid state reactions. [11] The advantages of the LZH for the drug delivery includes improved delivery of poorly water-soluble drugs, [12] lowered systemic toxicity of drug, [13] and the ability to optimise drug release rate. [14] LZH nanocarriers are unstable in low pH medium when dissolved in liposomes at pH 4.5À5, zinc anions released and become part of the nutrient cycle.…”

NO decomposition, storage and reduction over novel mixed oxide catalysts derived from hydrotalcite-like compounds

“…The superlattice formation in the brucite-like layers enables us to finely tune the catalytic properties of HTlcs and derived mixed oxides by carefully selecting the combination of the catalytic metal elements. In the derived mixed oxides, the uniform cationic distribution could be kept when the calcination temperature is lower than 600 • C, or even 800 • C since the transformation from HTlcs to the mixed oxides follows a topotactic process [37][38][39][40]. Therefore, the derived mixed oxides could have higher surface area, good dispersion of the active components in space, and relatively higher hydrothermal stability, which are all good properties for the design of efficient NSR catalysts as either the catalyst supports or the direct catalysts.…”