**3. Preparation and catalytic properties of some functionalized gold nanocomposites**

In this section, many examples have been investigated, including the synthesis of gold nanoparticles by some compounds with hydrophilic spacers and aromatic headgroups at different interface. The obtained experimental data indicated that various gold nanostructures could be prepared by controlling different substituted headgroups in template compounds. In addition, the photocatalytic capacities of as-prepared gold nanoparticles on the degradation of organic dyes were also demonstrated.

**Figure 12.** UV–Vis spectra and AFM images of organized LB films containing gold nanoparticles.

**Figure 11.** N2 adsorption–desorption isotherms (a) and pore size distributions of samples (b).

1s region, (c) Ca 2p region, and (d) Mn 2p region.

258 Advanced Catalytic Materials - Photocatalysis and Other Current Trends

**Figure 10.** XPS spectrum of La0.6Ca0.4MnO3–graphene composite. (a) Overall spectrum, high-resolution curves of (b) O

Firstly, the effect of gemini compounds on in situ self-assembly and fabrication of gold nanoparticles in organized molecular films have been demonstrated [42]. In comparison with traditional compounds, gemini molecules demonstrated well the capacity to fix chloroaurate ions onto various solid substrates, suggesting an important route to prepare metallic nano‐ particles in organized films by chemical reduction method. In addition, gemini compounds could produce a 2D confined environment in LB films to accommodate the formed gold nanoparticles. Thus, the size, shape, and interparticle distances can be regulated by changing various reducing methods. Various nanostructures could be fabricated, such as nanoparticles, nanowires, and the tree-branched domains. Based on the obtained experimental results, different gold nanostructures could be synthesized by regulating various reductants or reducing processes. Moreover, we tried to control gold nanostructures by optical method. The obtained composite film was irradiated with UV light and then reduced by AuCl4 ions with hydroquinone, as seen in Figure 12. The present research work provided the new clue for the synthesis of metallic particles in films from special compounds, showing important explora‐ tion in designing various gold nanostructures.

In addition, we presented a facile synthetic method to the gold nanostructures using a series of gemini amphiphiles through liquid–liquid biphase method [43]. The gemini amphiphiles themselves could serve as both capping and reducing agents. The spacer and concentration of the gemini amphiphiles played an important role in the formation of gold nanoprisms. It is predicted that gold and other novel metal nanostructures may be produced by gemini amphiphiles whose properties can be well controlled by designing different headgroups, spacers, or alkyl chains. In order to make clear the gold nanostructures, the chloroform solution was cast onto copper grid for TEM measurement, as shown in Figure 13. For gold nanostruc‐ tures generated by GN1, a few polygon gold nanoparticles were found. In contrast, uniform gold nanoparticles with a size of 11.4 ± 1.2 nm were observed in GN2 chloroform solution. Interestingly, in GN3 chloroform solution, triangular nanoplates and nanoparticles were both observed. The obvious difference suggests that the spacer has an influence on the shapes of gold nanostructures. On the other hand, no gold nanoparticle can be observed in aqueous phase no matter how long the reaction proceeded.

Considering the above research background, we have prepared new kinds of gold nanopar‐ ticles via some bolaform Schiff base compounds with hydrophilic spacers and aromatic headgroups in molecular skeletons [44]. By stirring the mixed solution of aqueous AuCl4 − ions with chloroform solution of used Schiff base molecules, the metal ions shifted to the chloroform phase and reduced to the formation of different gold nanoparticles. The data indicated that different gold nanostructures could be obtained by regulating the molecular skeletons of used bolaform compounds, including spacers and headgroups, as well as the relative ratios of compounds to metal ions. In addition, the characterization of morphologies and spectra indicated that the present designed bolaform amphiphilic compounds could act as both capping agents and reducing agents. So the UV–Vis spectra in different conditions are demonstrated, as seen in Figure 14. From the obtained UV–Vis data, it clearly indicated that the spacer and azomethine segments in bolaform molecules could be positively charged at interface in transferred process. In addition, the photocatalytic capacity of the obtained gold nanoparticles on dye degradation was demonstrated in Figure 15, showing the influence of molecular skeletons in the used compounds on the regulation of prepared gold nanoparticles and next catalytic behaviors. The present obtained data suggested that various gold nano‐ structures could be designed and synthesized by changing substituted skeletons in used template compounds

nanowires, and the tree-branched domains. Based on the obtained experimental results, different gold nanostructures could be synthesized by regulating various reductants or reducing processes. Moreover, we tried to control gold nanostructures by optical method. The

hydroquinone, as seen in Figure 12. The present research work provided the new clue for the synthesis of metallic particles in films from special compounds, showing important explora‐

In addition, we presented a facile synthetic method to the gold nanostructures using a series of gemini amphiphiles through liquid–liquid biphase method [43]. The gemini amphiphiles themselves could serve as both capping and reducing agents. The spacer and concentration of the gemini amphiphiles played an important role in the formation of gold nanoprisms. It is predicted that gold and other novel metal nanostructures may be produced by gemini amphiphiles whose properties can be well controlled by designing different headgroups, spacers, or alkyl chains. In order to make clear the gold nanostructures, the chloroform solution was cast onto copper grid for TEM measurement, as shown in Figure 13. For gold nanostruc‐ tures generated by GN1, a few polygon gold nanoparticles were found. In contrast, uniform gold nanoparticles with a size of 11.4 ± 1.2 nm were observed in GN2 chloroform solution. Interestingly, in GN3 chloroform solution, triangular nanoplates and nanoparticles were both observed. The obvious difference suggests that the spacer has an influence on the shapes of gold nanostructures. On the other hand, no gold nanoparticle can be observed in aqueous

Considering the above research background, we have prepared new kinds of gold nanopar‐ ticles via some bolaform Schiff base compounds with hydrophilic spacers and aromatic headgroups in molecular skeletons [44]. By stirring the mixed solution of aqueous AuCl4

with chloroform solution of used Schiff base molecules, the metal ions shifted to the chloroform phase and reduced to the formation of different gold nanoparticles. The data indicated that different gold nanostructures could be obtained by regulating the molecular skeletons of used bolaform compounds, including spacers and headgroups, as well as the relative ratios of compounds to metal ions. In addition, the characterization of morphologies and spectra indicated that the present designed bolaform amphiphilic compounds could act as both capping agents and reducing agents. So the UV–Vis spectra in different conditions are demonstrated, as seen in Figure 14. From the obtained UV–Vis data, it clearly indicated that the spacer and azomethine segments in bolaform molecules could be positively charged at interface in transferred process. In addition, the photocatalytic capacity of the obtained gold nanoparticles on dye degradation was demonstrated in Figure 15, showing the influence of molecular skeletons in the used compounds on the regulation of prepared gold nanoparticles and next catalytic behaviors. The present obtained data suggested that various gold nano‐ structures could be designed and synthesized by changing substituted skeletons in used


ions with

− ions

obtained composite film was irradiated with UV light and then reduced by AuCl4

tion in designing various gold nanostructures.

260 Advanced Catalytic Materials - Photocatalysis and Other Current Trends

phase no matter how long the reaction proceeded.

template compounds

**Figure 13.** TEM images of reduced gold in GN1 (a), GN2 (b), and GN3 (c) chloroform solution after 36 h of reaction respectively.

**Figure 14.** UV–Vis spectra of 0.1 mM AuCl4 ions and prepared gold nanostructures in aqueous solution.

**Figure 15.** AFM images of height and 3D surface plot view with depth histogram of gold nanoparticles on mica pre‐ pared from instant ultrasonic ethanol solution with SN2 to chloroaurate ion ratio of 2:1 after 35 h of reaction.

In addition, some other gold nanoparticles were synthesized by two bolaform cholesteryl imide derivatives with different lengths of ethyleneamine spacers at a liquid–liquid interface [45]. Spectral and morphological measurements indicated that both bolaform amphiphiles could act as both capping agents and reducing agents. To further characterize the prepared gold nanostructures, TEM measurements have been demonstrated, as seen Figure 16. The images indicated that the size distribution of obtained gold nanostructures could be regulated by changing various spacers in used molecular skeletons. In addition, the effect of molar ratio of the template compound to AuCl4 – ions was also investigated in details. The experimental data indicated that various nanostructures, such as hexagonal, polygon nanoparticles, and nanoplates, could be synthesized. Moreover, the photocatalytic capacity of prepared gold nanostructures on dye degradation was also characterized, suggesting the importance of compounds' skeletons in regulating the formation of gold nanoparticles and changing relative catalytic properties, as demonstrated in Figure 17. The obtained research data would give new clue for the preparation of gold nanostructures by designing special template compounds.

**Figure 16.** TEM images of gold nanoparticles by using different compounds to chloroaurate ion ratio.
