A Comparative Study of ZnS–ZnO Nanocomposite Assembly for Photocatalytic Removal of Crystal Violet Dye

Abstract

Herein, the effect of composition on the optical and photocatalytic performance of ZnS–ZnO composite is described. The composite samples are synthesized by chemical precipitation method using (NaOH + Na2S) mixture as the precipitating agent. The chemical composition of precipitating agent results in in situ formation of ZnO and ZnS. Lower content of NaOH in precipitating agent solution (1:3 by volume) exhibits the formation of ZnS, while, its higher concentration induces the phase separation with higher volume fraction of ZnO as observed from X‐ray diffraction patterns. Optical studies suggest the enhancement of visible absorption along with redshift in the absorption edge of composites as compared with bare ZnS nanoparticles (NPs). Moreover, the incorporation of ZnO with ZnS is also supported by optical emission spectra in which intense emission around 507 nm is associated with S‐species. ZnO encapsulation on ZnS NPs exhibits higher emission associated with O‐ defects as compared to S‐species. Since both are near‐UV excited semiconductors, both contribute toward the generation of charge carriers to produce radicals and hence photo‐oxidation of crystal violet dye. Further, little concentration of ZnO with ZnS NPs exhibits comparable photocatalytic efficiency (≈88%) that is observed with other ZnS–ZnO nanocomposite samples.

Synthesis of multi-phases MoO3-MoS2-Mo2S3 nanostructure catalyst for degradation of methylene blue, rhodamine B, and crystal violet dyes

“…This process is intrinsically linked to the size of the photocatalyst, the concentration of OH ). The absorption spectra of these dyes feature characteristic peaks at wavelengths of 665 nm, 557 nm, and 590 nm for MB, RhB, and CV dyes, respectively [3,28,88]. The absorption intensity at each peak reduced from ∼2.45 a.u.…”

“…Particularly noteworthy is its enhanced affinity for CV dye molecules, which exhibit a more positive charge, and its capacity to capture CV dye efficiently, thereby elevating catalyst activity via oxidation/reduction reactions. [1,88,91]. The inherent wide bandgap energy of molybdenum oxides (MoO 3, MoO 2 ) serves as the shell layer and suppression layer, inducing the quantum confinement effect and effectively inhibiting the tunable electronic effect.…”

ZnSe-rGO nanocomposites as photocatalysts for purification of textile dye contaminated water: A green approach to use wastewater for maize cultivation

“…(where CV = Crystal Violet, MV = Methyl violet, MB = Methylene Blue). Photocatalyst Dye Light source Time (min) Degradation (%) Reference CuCo 2 O 4 MV Sunlight 60 93 [ 56 ] GO/NiS CV Sunlight 80 91.01 [ 57 ] SnO 2 MV Sunlight 120 80 [ 58 ] Mg-doped ZrO 2 MV UV 70 92 [ 59 ] Co(II) based coordinate polymer MV UV 50 86.1 [ 60 ] NiO/Cr 2 O 3 CV Sun light 180 88.47 [ 61 ] ZnS–ZnO NC CV UV 180 88.36 [ 62 ] ZnS QD MV UV 120 91.4 [ 63 ] MgFe ...…”