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Exfoliated polystyrene/layered double hydroxide (PS/LDH) nanocomposites were prepared by direct intercalation of PS into MgAl LDH at 60 o C. The MgAl LDH as nanofiller was modified via the precipitation of the salt mixture of magnesium and aluminum metals by sodium dodecyl sulfate (SDS). Various techniques, Fourier Transformed Infrared Spectroscopy (FTIR), X-Raydiffraction (XRD), Filed Emission Transmission Electron Microscopy (FETE) and Thermo gravimetric analyses (TGA) were employed for structural properties and thermal stability of the nanocomposites. FTIR spectra indicated the presence of both functional groups of SDS-LDH and PS. XRD patterns and TEM images indicated the formation of amorphous dispersed and exfoliated nanocomposites. Increase in thermal stability with SDS-MgAl LDH content was observed by TGA and DTG through the T 0.5 (T 0.5 the degradation temperature at 50%) and T max (T max the maximum rate of change) with a maximum obtained for a loading of 2 and 4 wt%.13 samples were disorderly dispersed and exfoliated into the PS matrix with some aggregated regions, which is in a good agreement with previous studies. 46, 48 Therefore, TEM results confirmed the results of XRD patterns, where the images of TEM showed that all nanocomposite samples prepared by this method were disorderly dispersed and exfoliated into the PS matrix. Fig.5. depicts the schematic diagram of the synthesis mechanism of the MgAl LDH, SDS-MgAl LDH via co-precipitation method and PS/SDS-MgAl-LDH nanocomposites via direct intercalation method depending on the obtained results from XRD and TEM.

Developing green, cheap technology for large‐scale production of photocatalysts in colloidal dispersion form enables the fabrication of efficient sunlight‐responsive immobilized photocatalytic systems to address current environmental issues. It is reported for the first time, a cost‐effective, energy‐efficient, green, single‐step approach for solar‐driven fixation of bismuth oxybromideiodied solid solution (BiOBr0.75 I0.25 SS) on reduced graphene oxide (rGO) sheets by solar light irradiation of BiOBr0.75I0.25‐graphene oxide (GO) dispersion in ethanol medium. Upon solar irradiation, GO is photocatalytically reduced by BiOBr0.75I0.25, resulting in uniform fixation of BiOBr0.75I0.25 SS on rGO to yield high‐purity BiOBr0.75I0.25‐rGO heterojunction (BiOBr0.75I0.25‐rGO HJ) in colloidal dispersion form. The solar‐driven fixation of BiOBr0.75I0.25 SS on rGO brings many favorable characteristics for BiOBr0.75I0.25‐rGO HJ as sunlight‐responsive photocatalyst over the pristine BiOBr0.75I0.25, including high absorption of light in the visible region, high electron‐hole separation efficiency, and super adhesive property. As a result, BiOBr0.75I0.25‐rGO HJ films exhibit super durability and outstanding photocatalytic performance for water decontamination over BiOBr0.75I0.25 films under the same conditions. This study is an establishment of a green strategy for the large‐scale production of rGO‐based bismuth oxyhalides HJs.

the photoinduced charge carriers. [8][9][10] Besides, it is highly desirable to achieve these goals using earth-abundant materials and a cost-effective, energy-efficient, and scalable preparation strategy for large-scale photocatalytic systems.Recently, bismuth oxyhalides (BiOXs, X = Cl, Br, and I) have demonstrated excellent photocatalytic activity under sunlight irradiation due to their distinct characteristics such as indirect bandgap, excellent electronic configuration, unique layered structures, high dipole moment, powerful oxidation ability, and high separation rate of photogenerated electron-hole pairs. [11][12][13][14] Despite the distinct optical and structural characteristics of BiOXs, they show some drawbacks that limit their practical application. For instance, BiOBr has a narrow bandgap energy ≈2.7-2.8 eV absorbing the visible light component of the solar spectrum; however, its photocatalytic performance is relatively poor due to its low separation rate of charge carriers and weak oxidation ability. [8,15] On the other hand, BiOCl possesses a more powerful oxidation ability but with a wide bandgap energy (≈3.3 eV), thus responding to only UV light, which represents a small percentage (≈5%) of the solar spectrum, and reducing its chance for scalable remediation of environmental pollution. [16,17] Consequently, the integration of the desired characteristics of individual BiOXs in one photocatalytic compound is an effective strategy to produce more efficient BiOXs-based photocatalytic systems. For example, alloyed compounds (i.e., solid solutions) of BiOXs which contain more than one halogen atom in the compound through changes in the molar ratios of halogen atoms such as BiOCl x Br 1−x , [18,19] BiOCl x I 1−x , [20,21] and BiOBr x I 1−x . [22,23] have the same layered atomic structure, leading to the easy arrangement of different halogen atoms into the lattice of solid solutions using a low-energy fabrication process. Based on this fact, the solid solutions strategy is one of the most effective ways to improve the photocatalytic performance of BiOXs by reaching the best balance between the visible light absorption and reduction-oxidation (redox) abilities. [19,20,23] Among the different solid solutions of BiOXs, flower-like BiOCl x Br 1−x solid solutions (i.e., engineering BiOCl by introducing different molar ratios of Br) demonstrate superior photocatalytic performance compared to their counterparts. In previous studies, BiOCl x Br 1−x solid solutions were prepared by following two typical strategies, either by introducing organic salts (cetyltrimethylammonium bromide (CTAB) and cetyltrimethylammonium chloride (CTAC)) as a source for halogen with different molar ratios using multistep methods at ambient conditions [19,24,25] or by using simple salts (KCl and KBr) as a source for halogen ions using the hydrothermal or solvothermal methods. [26][27][28] In fact, the first strategy is a lengthy process that requires expensive and complex organic materials as halogen sources and indisposable surfactants, ...

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