Sanmitra Barman

Sanmitra Barman1 | Bipin Singh1 | Arijit Bag2 | Arun Singh Patel3 | Anirban Chakraborti1 | Abhimanyu Rana1
In this paper, a novel composite photocatalyst, ferric oxide–bismuth oxyhalide
(Fe2O3-BiOCl0.5Br0.5) has been synthesized, characterized, and used for the
degradation of methyl orange through advanced oxidation process under ambient
conditions (sunlight, pH 7.0, and temperature 25
C). The catalyst has been
characterized by using UV-Vis spectrophotometer, Fourier transform infrared
(FTIR) spectroscopy, Raman spectrometer, scanning electron microscopy
(SEM), energy dispersive X-ray analysis (EDX), and X-ray diffractometer
(XRD) techniques. The catalyst shows appreciable activities under natural sunlight
conditions. From the XRD patterns and SEM images, it is observed that
the elongation along the z axis in the crystal lattice of BiOCl0.5Br0.5 in the catalyst
can lead to a lattice distortion induced internal electric field which can
help in charge carrier separation and transport. The Fe2O3-BiOCl0.5Br0.5 catalyst
shows more than 90% photodegradation efficiency of methyl orange in
90 min of sunlight exposure. The presence of magnetic ferric oxide in the composite
photocatalyst helps to isolate the catalyst from the reaction mixture by
using an external magnet, and thus, the Fe2O3-BiOCl0.5Br0.5 catalyst can be
reused repeatedly, towards degradation of organic pollutants.

Waseem Ashrafa, Shikha Bansala, Vikrant Singhb, Sanmitra Barmanb and Manika KhanujaORCID logo*a
This report presents the superior visible-light-driven photocatalytic response of novel 2D/2D BiOCl/WS2 (BWX) hybrid nanosheet heterojunctions prepared by a simple solution based sonochemical technique. These BWX hybrid nanosheets are composed of 2D transition metal dichalcogenide material WS2 and BiOCl nanosheets. The comparative study of photocatalytic activity of BiOCl and BiOCl/WS2 hybrid nanosheets is carried out via photodegradation of Malachite Green (MG) and photoreduction of heavy metal ion Cr(VI) under visible light irradiation. The quantum efficiency of the samples is estimated in terms of the incident photon to electron conversion efficiency (IPCE) measurements. Nearly 98.4% of the MG degradation was achieved over BiOCl/WS2 (2%) photocatalyst in 45 min of irradiation. BiOCl/WS2 (2%) hybrid nanosheet catalyst showed the highest external quantum efficiency (EQE) in both the UV and visible regimes. This accomplishment demonstrated the promise of commercial application of the 2D/2D BiOCl/WS2 (2%) hybrid nanosheet photocatalyst.