Influence of Molar Ratio of Zn/Al/Tyr on the Formation of Tyr/Zn‐Al‐LDH Nanohybrids

Abstract

The intercalation of amphoteric amino acid tyrosine (Tyr) into LDH by co-precipitation method was systematically studied. The influence of initial molar ratios (R) of LDH to Tyr has also been examined. Powder X-ray diffraction, Fourier transform infrared spectroscopy, specific surface areas and pore size distributions, and thermal analysis have been employed for the characterization of the nanocomposites. The nanohybrids were found to have an expanded layered structure except the samples prepared with low R values, indicating that the biomolecules were intercalated into the gallery as anions. The intercalation of amino acids resulted in the increase of the surface areas and pore volumes, and the value of surface areas and pore volumes increased with enhancement of biomolecules intercalated. TEM analysis revealed that with increasing biomolecules into the gallery, the nanohybrids were changed from hexagonal particles to spherical ones. Moreover, the configuration of Tyr anions was varied under different R values, changed from monolayer to bilayers with more biomolecules intercalating into the gallery.

Hydrothermal synthesis, crystal structure and spectroscopic properties of a novel 3D chromium(III) complex

“…The decomposition of the ligand began at 380°C and ended at 490°C to form the second loss step with the lost weight of 33.99% (calculated value 33.55%). Weight loss sequence is consistent with previous reports [27][28][29].…”

Organic-Inorganic Nanohybrids of Biologically Important Molecules and Layered Double Hydroxides

“…Anions of L-tyrosine [21][22][23][24][25][26][27][28][29][30][31], glycine [24,[32][33][34], L-alanine [24,32], L-leucine [24,32], L-phenylalanine [21-25, 32, 34-37], L-serine [24,32], L-tryptophan [24,32], Llysine [24], L-arginine [24], L-histidine [24,32], L-aspartic acid [20,24,32,[38][39][40][41][42], L-glutamic acid [20,24,32,41], L-asparagine [24,32], L-glutamine [24,32], L-proline [32,42,43], L-glutamic acid [32,44], L-cysteine …”

“…The L-tyrosine anion could be intercalated by direct anion exchange [21][22][23] as well as the co-precipitation method [26][27][28][29][30][31]. The host materials were MgAl-LDH [26,29], ZnAl-LDH [26][27][28]30] and NiAl-LDH [26,29].…”

“…For the ZnAl-LDH/Tyr system it was established that the interlayer distance, consequently, the interlayer arrangement of the amino acid carboxylate ion depended on the pH of co-precipitation [26] -it increased with the decrease of the pH -, the molar ratio of the amino to the LDH [27] -it increased with the increase of the ratio -, the aging time [30] -it had an optimum if achieving the maximum interlayer distance was the goal -and the temperature of calcination [31] -it decreased with increasing temperature. Between the layers of ZnAl-LDH, the intercalated anions either formed a monolayer with the longest axis perpendicular or bilayer with axis tilted with a high angle to the layers of the ZnAl-LDH host, depending on the synthesis conditions or the treatments thereafter [26][27][28][29][30][31]. A detailed modeling study indicated bilayer arrangement with the two guest layers immersing to each other through stacking interactions [25].…”