Synthesis of Fe2O3–NiO–Cr2O3 composites from NiFe-layered double hydroxide for degrading methylene blue under visible light

•NiFe-layered double hydroxide with dichromate was used to prepare Fe2O3–NiO2–CrO3.•The Fe2O3–NiO2–CrO3 composites' absorption edge intensely extended up to ca. 700 nm•The Fe2O3–NiO2–CrO3 composite showed high catalysis under the visible light.•Very high methylene blue degradation of 91.2% was achieved with composite in H2O2.

To develop a low-cost and highly efficient photocatalyst under the visible illumination, Ni3Fe–CO3–LDH (referred to hereafter as NiFe-layered double hydroxide or NiFe–LDH) was used as a precursor to synthesize Fe2O3–NiO–Cr2O3 composite. The NiFe–LDH was prepared by co-precipitation and then it was exchanged with dichromate. After calcining at 600 °C, the Fe2O3–NiO–Cr2O3 composite was obtained. The composites' absorption edge intensely extended up to ca. 700 nm covering the full visible light spectrum and showed high catalytic activity at natural pH under the visible light illumination. A very high methylene blue degradation of 91.2% was achieved with the aid of H2O2 in 120 min with no detectable Cr in solution.

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