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Abstract
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The Zn 2 SnO 4 /MWCNTs (ZSC) nanocomposite was synthesized by a facile two-step process. The as-
prepared
nanocomposite was characterized by Powder X-ray diffraction, scanning electron microscopy,
Transition
electron microscopy, UV–vis diffuse reflectance spectroscopy and photoluminescence spectra
analysis.
The ZSC nanocomposite exhibits much higher photocatalytic activity (94% removal in 120 min) in
comparison
with bare Zinc stannate (ZS) (17% removal in 120 min) under UV-A irradiation, toward degra-
dation
of Basic Red 46. The role of the MWCNTs on the observed enhancement in photocatalytic activity
was
revealed by investigating the effect of radical scavengers on degradation efficiency. The addition of
BQ
had no effect on photocatalytic efficiency and t-buthanol decreased the photocatalytic activity to some
extent.
However, the addition of iodide ion, as a hole scavenger, inhabited completely the photocatalytic
degradation
of BR46, indicating that the degradation of the BR46 occurs mostly by direct oxidation on
photogenerated
holes. Based on the results of experiments, DRS and PL spectra, two possible mechanisms
were
proposed. Moreover, a new kinetic model was developed based on the intrinsic elementary reac-
tions
and the proposed mechanism. The correlation coefficient (R 2 ) and root-mean-square-error (RMSE)
of
0.990 and 7.12 × 10 −4 indicates the good agreement between the calculated apparent rate constants
and
experimental ones.
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