Figure 2. (A) Schematic diagram of preparation process of monolayer LDH nanosheets; (B) Schematic diagram of LDH modification by TA; (C) FTIR spectra of LDH and TA@LDH; (D) Partial magnification of FTIR spectra.
Single-layer LDH nanosheets rich in hydroxyl groups were obtained by delaminating MgAl(NO3)-LDH in formamide (Figure 2A). Then, the surface of the monolayer LDH nanosheets was modified by TA (Figure 2B). Upon irradiation by a red laser, the LDH and TA@LDH suspensions both show clear Tyndall effect, indicating their homogeneity (Figure S3 A and B, Supporting information). The interaction between TA and LDH was investigated by FTIR spectra (Figure 2C). The LDH and TA@LDH both display obvious absorption peaks at 3500 cm−1 and 1642 cm−1, which are ascribed to stretching and bending vibration absorption of O−H. For LDH sample, a strong sharp absorption peak at 1384 cm−1 is attributed to the antisymmetric stretching vibration of NO3. Bending vibration of M−O−M appears at 837 cm−1, which shifts to 880 cm−1 after hybridization with TA. The blue shift of M−O−M absorption band for the TA@LDH sample suggests the formation of hydrogen bonds between TA and LDH.