Enhanced Photocatalytic Degradation of Methylene Blue Using <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:mrow><mml:msub><mml:mrow><mml:mtext>ZnFe</mml:mtext></mml:mrow><mml:mtext>2</mml:mtext></mml:msub><mml:msub><mml:mtext>O</mml:mtext><mml:mtext>4</mml:mtext></mml:msub></mml:mrow></mml:math>/MWCNT Composite Synthesized by Hydrothermal Method

Abstract

Multiwalled carbon nanotubes (MWCNTs) were synthesized using arc discharge method at a magnetic field of 430 G and purified using HNO 3 /H 2 O 2 . Transmission electron micrographs revealed that MWCNTs had inner and outer diameter of ~ 2 nm and ~ 4 nm, respectively. Raman spectroscopy confirmed formation of MWCNTs showing G-band at 1577 cm −1 . ZnFe 2 O 4 and ZnFe 2 O 4 /MWCNT were produced using one step hydrothermal method. Powder X-ray diffraction (XRD) confirmed the formation of cubic spinel ZnFe 2 O 4 as well as incorporation of MWCNT into ZnFe 2 O 4 . Visible light photocatalytic degradation of methylene blue (MB) was studied using pure ZnFe 2 O 4 and ZnFe 2 O 4 /MWCNT. The results showed that ZnFe 2 O 4 /MWCNT composite had higher photocatalytic activity as compared to pure ZnFe 2 O 4 . After irradiation for 5 hours in the visible light, MB was almost 84% degraded in the presence of ZnFe 2 O 4 photocatalyst, while 99% degradation was observed in case of ZnFe 2 O 4 /MWCNT composite. This enhancement in the photocatalytic activity of composite may be attributed to the inhibition of recombination of photogenerated charge carriers.