Abstract:
Persistent organic pollutants have been a global threat. The need for a cost-effective and
environmentally benign method for the degradation of these contaminants has led to tremendous
research in photocatalysis. Bismuth based semiconductors have emerged as very promising visible
light-activated catalysts. In this thesis, we introduce a method to control the heterostructure
of Cu2O/BiOBr via a low-temperature hydrothermal procedure. Controlling the reaction
conditions via in situ and sequential approaches enabled the preparation of wellinterfaced Cu2O nano cubes over BiOBr nanosheets. The size, composition, morphology, and
structure of the material were characterized by transmission electron microscope (TEM), scanning
electron microscope (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and
X-ray photoelectron spectroscopy (XPS). The TEM and SEM illustrated the well-formed cubic
shape of the Cu2O nanoparticles as well as the tetragonal structure of BiOBr nano material. XRD
patterns that showed the crystal phase of the composite was obtained and the EDS showed that Bi,
Cu, and Pd were present in the composite. XPS spectra showed the surface chemical composition
and the chemical states of BiOBr/Cu2O matching those of literature. The activity and stability of
the photocatalysts and the role of scavengers were evaluated in the degradation of rhodamine B
and methyl orange organic dyes. Tuning the composition of the heterostructured photocatalysts
led to substantial increase in in the photocatalytic degradation of both cationic and anionic organic
contaminants. BiOBr/Cu2O photocatalyst was employed in the photocatalytic degradation of
glyphosate, a widely used herbicide that has shown adverse effects on human health and its toxic
by-product α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA). The composite
photocatalyst demonstrated complete degradation of glyphosate within 10 minutes of light
irradiation with a rate constant of 0.3674 min-1
using sequential synthesis route. Palladium
nanodomains were anchored selectively on the surface of Cu2O via a light-activated deposition
approach. The multicomponent Pd/BiOBr/Cu2O photocatalyst demonstrated diminished
photocatalytic degradation activity compared to the bare material. The stability of the BiOBr/Cu2O
photocatalyst was evaluated by following the degradation of rhodamine B for 4 consecutive cycles.
There was high activity and substantial stability of the BiOBr/Cu2O photocatalyst in the
degradation of Rhodamine B under simulated sunlight.
