Indulgent of the physiochemical features of MgCr-LDH nanosheets towards photodegradation process of methylene blue

In the present work, we report the preparatory strategy of MgCr-layered double hydroxide (LDH) nanosheets with 90% degree of delamination by employing a formamide-assisted co-precipitation and mild hydrothermal route for the degradation of methylene blue (MB) under solar light exposure. The as-synthesized MgCr-LDH nanosheets were characterized by assorted characterization techniques such as powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), Raman, thermogravimetric analysis (TGA), N-2 adsorption-desorption measurement, X-ray photoelectron spectroscopy (XPS) and UV-Visible diffused reflectance spectroscopy (UV-DRS). The XRD pattern of MgCr-LDH nanosheets quantified the strain (epsilon) and dislocation density (delta) of 1.371 lines(-2) m(-4) and 0.5723 lines m(-2) related to the (11 0) plane with d-spacing value of 1.6169 angstrom. With a minimum band gap of similar to 2.63 eV, the as-synthesized MgCr-LDH nanosheets displayed 90.6% MB photodegradation under the experimental protocols such as catalyst dosage of 30 mg/L, initial MB concentrations of 20 ppm, pH of 7 and time duration of 2 h under solar light exposure. Further, the recyclability test of the photocatalyst signifies material stability up to four successive cycles with 90% retention of MB degradation under sunlight exposure. The superior catalytic performances of the MgCr-LDH nanosheets could be ascertained to the suppression of excitonic recombination and effective light harvestation properties, synergistically contributed by the porous structural aspects via associatio n of uni/multi-lamellar nanosheets, surface defect sites and photoactive Cr3+ cations. Additionally, the surface -OH groups of LDH contributed towards the generation of (OH)-O-center dot radicals for triggering the catalytic performances. This type of work advances the novel ideas for establishing highly potent photocatalysts via synergizing structural and surface properties, paving towards effective wastewater treatment. (c) 2022 Elsevier Inc. All rights reserved.

Automated summary

The 90% delaminated MgCr-layered double hydroxide (LDH) nanosheets were prepared via a formamide-assisted co-precipitation and mild hydrothermal route for the degradation of methylene blue (MB) under solar light exposure. The as-synthesized MgCr-LDH nanosheets displayed a band gap of approximately 2.63 eV and achieved 90.6% MB photodegradation under specific experimental conditions. The superior catalytic performances were attributed to the suppression of excitonic recombination, effective light harvestation properties, and the contribution of porous structural aspects, surface defect sites, and photoactive Cr3+ cations.