MnFe2O4 decorated reduced graphene oxide heterostructures: Nanophotocatalyst for methylene blue dye degradation. (March 2020)

• Record Type: Journal Article
• Authors: Mandal, Bidisha; Panda, Jnanranjan; Paul, Pabitra Kumar; Sarkar, Ratan; Tudu, Bharati
• Is Part Of: Vacuum. Volume 173(2020)
• Publication Date: 2020-03
• Subjects: Manganese ferrite -- Graphene oxide -- Heterostructures -- Photocatalysis -- Degradation -- Methylene blue; Vacuum -- Periodicals; 621.55
• DOI: 10.1016/j.vacuum.2019.109150
• Languages: English
• ISSNs: 0042-207X

Abstract

Abstract: The photocatalytic degradation of methylene blue dye (MB) has been investigated using bare manganese ferrite (MnFe2 O4 ) nanoparticles and MnFe2 O4 nanoparticles-decorated reduced graphene oxide heterostructures (MnFe2 O4 /rGO) under ultra-violet irradiation. The MnFe2 O4 nanoparticles prepared using a facile co-precipitation method showed single-phase cubic spinel structure and superparamagnetic property. The MnFe2 O4 /rGO heterostructures showed the formation of sphere-like MnFe2 O4 nanoparticles well-attached on rGO nanosheets with reduced agglomeration. The photocatalysis study shows that MnFe2 O4 /rGO had higher photocatalytic activity compared to bare MnFe2 O4 nanoparticles. MB degraded by 84% in presence of MnFe2 O4 after UV irradiation of 290 min, while 97% of it degraded in merely 60 min in case of MnFe2 O4 /rGO heterostructures. This is further confirmed by the well-fitted Langmuir-Hinshelwood Kinetics equation. This improvement in the photocatalytic activity of the heterostructure is attributed mainly to the retardation of the recombination process of photo-generated charge carriers. Hydroxyl radicals play the crucial role in the MnFe2 O4 -graphene system for MB photodegradation. Thus, MnFe2 O4 nanoparticles-decorated reduced graphene oxide heterostructures can act as potential photocatalyst for degradation of hazardous organic dyes present in water. Graphical abstract: Image 1 Highlights: MnFe2 O4 and MnFe2 O4 /rGO nanophotocatalysts were successfully synthesized. MnFe2 O4 /rGO exhibits improved photocatalytic efficiency for Methylene Blue degradation. Hydroxyl radicals play important role in the MnFe2 O4 /rGO system for the photodegradation. Kinetic rate constant of MnFe2 O4 /rGO is about 10 times higher than that of MnFe2 O4 . Possible mechanism of photocatalytic degradation of Methylene Blue is proposed.