Photo-responsive behavior of γ-Fe2O3 NPs embedded into ZnAlFe-LDH matrices and their catalytic efficiency in wastewater remediation

• Nanocomposites of coupled γ-Fe2O3 nanoparticles(NPs)/LDHs matrices.
• Novel photocatalytic systems for wastewater remediation.
• Highly efficient catalysts for phenol, 2-nitrophenol and 2,4-dinitrophenol photodegradation.

We present here a fast, facile and cost-effective route to design efficient semiconductor/LDHs heterojunction photocatalysts based on γ-Fe2O3 nanoparticles (NPs)/ZnAlFe-LDHs matrices and their use as novel photocatalytic systems for wastewater remediation. Different compositions of ZnAlFe-LDHs were tailored by controlling the isomorphous substitution of Al3+ with Fe3+ as well as by the modulation of the Zn2+/(Al + Fe)3+ cationic ratio within the layers of the hydrotalcite-like matrix. The lowered band gap of the γ-Fe2O3NPs/ZnAlFe-LDHs enhanced the electron–hole pair formation under light illumination and increased the photocatalysts performances. The photodegradation studies on aqueous media containing several phenolic compounds (phenol, 4-nitrophenol and 2,4-dinitrophenol) revealed that the γ-Fe2O3NPs/LDHs assemblies show high catalytic efficiency producing the total degradation of the toxic organic compounds in short times. Further, this study provides new insights into the photodegradation mechanism of the phenolic compounds in aqueous media.

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