Tuning the structural, magnetic, and optical properties of ZnO/NiFe2O4 heterojunction photocatalyst for simultaneous photodegradation of Rhodamine B and Methylene Blue under natural sunlight

Abstract

The magnetic nanocomposites of ZnO/NiFe2O4 were synthesized using a hydrothermal method in organic solvent-free media for application as a heterojunction photocatalyst. XRD measurements confirmed the formation of the required phases of nanocomposites with no impurity phases observed. The SEM and TEM analysis confirmed the morphology and shape of composite as being spherical and square-like grain. The magnetic properties of composites measured using vibrating sampler magnetometer (VSM) under an applied field of ±2 T showed a soft ferromagnetism. Band gap energy of the ZnO/NiFe2O4 sample was found to be lower than the pure ZnO nanoparticles. The photocatalytic activity of samples was evaluated by monitoring the simultaneous degradation of the mixed dye model of Rhodamine B and Methylene Blue under visible-light irradiation. Compared with pure ZnO, the nanocomposites exhibited a better photocatalytic performance with a degradation percentage of 98% for Rhodamine B and 97% for Methylene Blue in mix solution after 3 h of irradiation.

Introduction and Advancements in Room-Temperature Ferromagnetic Metal Oxide Semiconductors for Enhanced Photocatalytic Performance

“…The increase in ferromagnetic character and photocatalytic efficiency for metal oxide semiconductors can arise from shared material properties, such as electronic band structure, defects, and charge carrier behavior [252][253][254][255]. However, it is important to evaluate each material system individually, as the correlations among these properties can vary based on specific conditions and material characteristics.…”

Introduction and Advancements in Room Temperature Ferromagnetic Metal Oxide Semiconductors for Enhanced Photocatalytic Performance

“…Complex Interplay: The relationship between magnetic character and photocatalytic efficiency is complex and not always linear. It's possible for these properties to be enhanced in tandem due to shared underlying mechanisms, but they can also exhibit opposing behaviours depending on factors such as material composition, crystal structure, and external conditions [161][162][163] The increase in ferromagnetic character and photocatalytic efficiency for metal oxide semiconductors can arise from shared material properties, such as electronic band structure, defects, and charge carrier behaviour [164][165][166][167]. However, it's important to evaluate each material system individually, as the correlation between these properties can vary based on specific conditions and material characteristics.…”

High performance Co3O4/Sn-ZnO nanocomposite photocatalyst for removal of methylene blue dye

“…Moreover, ZnO synthesized using simple template-free precipitation techniques showed 24.9% photocatalysis efficiency of MB dye under visible light irradiation [16]. This inherent poor photocatalytic properties of ZnO nanoparticles in visible light region can be modified using common strategies such as doping [17,20], making a composite [21,22], and construction of heterojunction [23,24], and combinations of the above strategies at the same time [25,26].…”

“…For instance, the photocatalytic degradation efficiency of methylene blue using ZnO was enhanced by doping such as Sb-ZnO synthesized by sonochemical-assisted precipitation and achieved an efficiency of 91% using 300 mg L −1 catalyst under solar irradiation due to reduction of band gap to visible region [17], Ag-ZnO synthesized by co-precipitation route exhibited an enhanced efficiency of 95% for MB dye removal using 500 W halogen lamp [18], Sn-ZnO synthesized by ultrasonication aided co-precipitation method completely removed MB dye under UV light irradiation [19] and hydrothermally synthesized Cu-ZnO showed 90% efficiency of MB dye degradation under UV light [20].The heterojunction of ZnO/NiO shows enhanced photocatalytic MB dye degradation efficiency of 70% compared to pure ZnO (53%), and NiO (2%) due to enhanced charge separation [23]. Furthermore, hydrothermally synthesized ZnO/NiFe 2 O 4 heterojunction degrades MB (97%) and Rhodamine B (98%) under visible light irradiation for 3 h due to reduction of the band gap and effectively reducing the recombination rate of e-h pairs [24].…”