*3.2.1 FE-SEM analysis*

for 24 h. Later, the autoclave was cooled down naturally. Finally, the obtained solution was centrifuged and washed with DDW water and dried at 80°C for

A certain amount of g-C3N4 was dispersed into 20 ml of DDW and ultrasonicated for 30 min. Subsequently, the ZnO\Mg-Al precursor solution was prepared and mixed with ultrasonicated g-C3N4 nanosheets. Again, the mixture was ultrasonicated for 30 min in a beaker to form a homogeneous suspension. After that, the reaction mixture was transferred into a 100 ml Teflon liner stainless-steel autoclave, followed by heating in an oven under 180°C for 24 h. After that, the autoclave was cooled down naturally to ambient temperature. Finally, the sample was centrifuged and washed with DDW water and dried at 80°C for overnight to obtain the final product. **Figure 2** shows the formation of g-C3N4\ZnO\Mg-Al LDH

The photocatalytic activities mostly depend on the material nature, specific surface area, and light energy utilization ratio [35] etc., and for these reasons the crystallinity, functional group, surface area morphology and photophysical properties of the as-prepared samples were systematically investigated by various analyt-

The crystalline phases have a significant influence on the photocatalytic activities [36]. So the phase purity and crystallite size of the synthesized samples were evaluated by X-ray diffractometer using Riguku MiniFlux-II diffractometer using

Cu Kα radiation (λ = 1.540 46 Å). The crystalline nature of the prepared

samples were investigated through XRD analysis and **Figure 3** displays the XRD pattern of Mg-Al LDH, gC3N4, ZnO and g-C3N4\ZnO\Mg-Al LDH ternary

The XRD pattern of the Mg-Al LDH and g-C3N4, sample is in good agreement with the JCPDS card no: 35-0965 [37] and 87-1526 [38], respectively. The diffraction peaks indexed to (003), (006), (012), (015), (018), and (110) are the plane reflections of a typical hydrotalcite-like phase screening, sharp and symmetric basal (00 l) reflection of LDH. The XRD pattern of ternary nanocomposite consists of g-C3N4, ZnO and Mg-Al LDH diffraction peaks indicate the formation of the

overnight to obtain the final product.

*Assorted Dimensional Reconfigurable Materials*

**2.4 Preparation of 2D\2D hybrid**

**3. Characterization details**

i. Structural investigation

iv. Photophysical investigation

v. Surface area investigation

ii. Morphology analysis

iii. Elemental analysis

**3.1 Structural investigation**

nanocomposite.

composite.

**108**

2D\2D hybrid.

ical techniques.

The surface morphology of the prepared samples was investigated by using FESEM and HRTEM analyses, respectively. The FE-SEM images were obtained by using Zeiss SUPRA-25 and the particle size and morphology of the prepared samples were analyzed by using HR-TEM – Jeol/JEM 2100, with LaB6 source.

**Figure 4** shows the FESEM images of (a) Mg-Al LDH, (b) g-C3N4, (c) ZnO and (d) gC3N4\ZnO\Mg-Al LDH ternary nanocomposite samples. The Mg-Al LDH consists of plenty of two-dimensionally structured hexagonal LDHs matrix with a layer by layer assembly. The size of the hexagonal nanoflakes is approximately 200 nm, which indicate the successful exfoliation of a 2D layer.

#### *3.2.2 HRTEM analysis*

Furthermore, the hexagonal formed hydrotalcite-like particles were seen from the HRTEM analysis (**Figure 4d** and **e**) and it concurs well with the morphology

#### **Figure 3.**

*XRD pattern of (a) Mg-Al LDH, (b) gC3N4, (c) ZnO and (d) g-C3N4\ZnO\Mg-Al LDH ternary nanocomposite [34].*

acquired from FE-SEM investigation. Some dull spots showed up on the outside of the LDH, demonstrating that the ZnO nanoparticles are well attached on the LDH surfaces. Some dark spots appeared on the surface of the LDH, indicating that the ZnO nanoparticles are well attached to the surface of the as-prepared LDH. The 2D\2D ternary nanocomposites assembly was successfully obtained, and by arresting the ZnO\Mg-Al LDH sheets with g-C3N4 sheets, the formation of the 2D\2D ternary nanocomposite was possible. Surprisingly, after the formation of the ternary nanocomposite, the LDH loose its horizontal stacking arrangements and started aligning vertically on the surface of the g-C3N4 nanosheets. These types of arrangements provide a more active surface for the prepared photocatalysts.
