Fast recombination
of photoinduced charge carriers is a major problem
in the case of semiconductor based photocatalysts, which must be solved
for their potential application in photocatalysis. In this work, photostable
CdS QDs/BiOI composites have been successfully fabricated by a two-step
precipitation–deposition method. The prepared samples were
characterized by X-ray diffraction (XRD), UV–vis diffuse reflection
spectroscopy (UV–vis DRS), photoluminescence (PL) spectroscopy,
transmission electron microscopy (TEM), X-ray photoelectron spectroscopy
(XPS), Mott–Schottky, and electrochemical impedance analysis.
The potential applications of CdS QDs/BiOI composite materials have
been tested toward decolorization of rhodamine B (RhB) solution and
hydrogen generation under solar light and visible light irradiation,
respectively. It has been observed that hydroxyl radicals, electrons,
and holes played a major role in decolorization of RhB solution. Among
all prepared photocatalysts, 4% CdS QDs/BiOI composite was able to
decolorize 82% of RhB solution in 1 h and 203 μmol/h of H2 under solar light and visible light irradiation, respectively.
The highest activity has been ascribed to optimal loading of CdS QDs,
good formation of composites, and the lowest recombination of charge
carriers.
In
this work, CdS quantum dots (QDs)-sensitized self-doped Bi
2
MoO
6
has been
synthesized using glucose as reducing agent by hydrothermal method,
followed by in situ deposition of the QDs. The synthesized catalyst
has been employed to reduce toxic Cr(VI) and degrade phenol from the
aqueous solution. The structural, optical,
and electrochemical characterizations are performed using X-ray diffraction,
UV–vis diffuse reflection, photoluminescence (PL), scanning
electron microscopy, transmission electron microscopy (TEM), Fourier
transform infrared spectroscopy, and electrochemical impedance spectroscopy.
The optical properties were precisely investigated by calculating
the Urbach energy, PL, and photoluminescence excitation spectra. The
orderly distribution of QDs is confirmed from the correlation between
full width at half-maximum of PL spectra, Urbach energy, and TEM analysis.
The versatile photocatalytic activity has been tested toward Cr(VI)
reduction and degradation of phenol. 3% CdS QDs-sensitized self-doped
Bi
2
MoO
6
showed highest activity, i.e., 97 and
47.5% toward reduction of Cr(VI) and degradation of phenol under solar
light. The reduction of Cr(VI) by the catalyst is supported by the
kinetics and determination of the pH
PZC
value. In addition
to this, the photostability and reusability test showed that the catalyst
can be reused up to five cycles without diminishing its activity.
ZnFe2O4 was fabricated by a simple solution-combustion method. The structural, optical and electronic properties are investigated by XRD, TEM, FESEM, UV–vis DRS, PL, FTIR and photocurrent measurements. The photocatalytic activity of the prepared material is studied with regard to the degradation of rhodamine B (Rh B) and Congo red under solar irradiation. The kinetic study showed that the material exhibits zeroth and first order reaction kinetics for the degradation of Rh B and Congo red, respectively. The photocatalytic behaviour of ZnFe2O4 was systematically studied as a function of the activation temperature. ZnFe2O4 prepared at 500 °C showed the highest activity in degrading Rh B and Congo red. The highest activity of ZnFe2O4-500 °C correlates well with the lowest PL intensity, highest photocurrent and lowest particle size.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.