Sulfur-and nitrogen-incorporated mesoporous TiO 2 (SNT) nanocomposites have been synthesized by a template-free homogeneous coprecipitation technique. The above nanocomposites have been thoroughly characterized by physicochemical and spectroscopy methods to explore the structural, electronic, and optical properties. The photocatalytic activities of the catalysts were evaluated for the degradation of methyl orange and phenol under direct solar light. SNT shows about a 2-fold higher photocatalytic activity than singly N-doped or S-doped mesoporous TiO 2 and 3-fold higher than Degussa P25. The higher activity might be attributed to the synergetic interaction of sulfate and nitrogen with the TiO 2 lattice. N-Ti-O and O-Ti-N-O environments are responsible for a red shift, and the sulfate group on TiO 2 acts as a cocatalyst, for increasing surface acidity as well as for sustaining the redox cycles for high stability.
During in situ thermal co-polymerization of melamine using boric acid and thiourea as the dopant, graphitic carbon nitride (g-C 3 N 4 ) co-doped with boron and sulfur has been successfully synthesized. The crystallographic, morphological, and spectroscopic data of synthesized materials were characterized through powder X-ray diffraction, transmission electron microsopy, elemental mapping, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, photoluminescence (PL), time-resolved PL (TRPL), and UV−vis diffuse reflectance spectroscopy techniques. The boron and sulfur doping in carbon nitride lattice enhance light absorption, charge separation, and migration and increase the effective surface area, constructing it to be the best photocatalyst among the bulk g-C 3 N 4 as well as singly doped C 3 N 4 counterparts for the generation of hydrogen. The introduction of dopants into the g-C 3 N 4 framework could tune the electronic property, suppress the recombination of photogenerated charge carriers, and trap photoinduced electrons by the defects created by the dopants. The bielemental doped C 3 N 4 shows excellent photocurrent response and a decrease in carrier recombination as suggested by linear sweep voltammetry, electrochemical impedance spectroscopy, and TRPL studies. The photocatalyst shows 11-and 8.5fold current enhancement in cathodic and anodic directions, respectively, as compared to the bulk g-C 3 N 4 which indicates both p and n type character in a single material. The synergistic effect contributed by boron and sulfur is responsible for achieving a high hydrogen evolution rate of about 53.2 μmol h −1 that is 8 times higher than that of bulk g-C 3 N 4 (6.6 μmol h −1 ). Density functional theory calculations have been performed to explore the HOMO−LUMO gap of synthesized materials.
In terms of solar hydrogen production, semiconductor-based
photocatalysts via p–n heterojunctions play a key role in enhancing future hydrogen reservoir.
The present work focuses on the successful synthesis and characterization
of a novel p-MoS
2
/n-CeO
2
heterojunction photocatalyst
for excellent performance toward solar hydrogen production. The synthesis
involves a simple in situ hydrothermal process by varying the wt %
of MoS
2
. The various characterization techniques support
the uniform distribution of CeO
2
on the surface of crumpled
MoS
2
nanosheets, and the formation of p–n heterojunction
is further confirmed by transmission electron microscopy and Mott–Schottky
analysis. Throughout the experiment, it is demonstrated that 2 wt
% MoS
2
in the MoS
2
/CeO
2
heterojunction
photocatalyst exhibits the highest rate of hydrogen evolution with
a photocurrent density of 721 μA cm
–2
. The
enhanced photocatalytic activity is ascribed to the formation of the
p–n heterojunction that provides an internal electric field
to facilitate the photogenerated charge separation and transfer.
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