1 research outputs found
Sonochemical-Assisted In Situ Electrochemical Synthesis of Ag/α-Fe<sub>2</sub>O<sub>3</sub>/TiO<sub>2</sub> Nanoarrays to Harness Energy from Photoelectrochemical Water Splitting
Numerous protocols
in heterostructure engineering hold promise
for effectively improving the optical properties of nanomaterials
for energy-harvesting applications. In this work, we successfully
fabricated Ag/α-Fe<sub>2</sub>O<sub>3</sub>/TiO<sub>2</sub> heterostructures
via electrochemical anodization assisted by pulse sonication. The
morphological features of the silver (Ag) deposited on α-Fe<sub>2</sub>O<sub>3</sub>/TiO<sub>2</sub> showed a layered distribution
of the α-Fe<sub>2</sub>O<sub>3</sub> nanoparticles (NPs) over
the TiO<sub>2</sub> nanotube arrays (NTAs), whereas Ag existed in
a pseudocubical form. X-ray diffraction (XRD) patterns and X-ray photoelectron
spectrometer (XPS) analysis validated the formation of α-Fe<sub>2</sub>O<sub>3</sub> and anatase TiO<sub>2</sub> crystalline phases
and Ag/α-Fe<sub>2</sub>O<sub>3</sub>/TiO<sub>2</sub> heterostructure.
The diffuse reflectance spectroscopy (DRS) UV–vis spectroscopy
results displayed a gradual decrease in the band gap with enhanced
absorption in the visible region of the spectrum due to optically
active heterostructure formation in the order Ag/α-Fe<sub>2</sub>O<sub>3</sub>/TiO<sub>2</sub> (470 nm) > α-Fe<sub>2</sub>O<sub>3</sub>/TiO<sub>2</sub> (424 nm) > TiO<sub>2</sub> (386
nm). The DRS absorption spectrum of Ag/α-Fe<sub>2</sub>O<sub>3</sub>/TiO<sub>2</sub> also exhibits a characteristic plasmon shoulder
of Ag at ∼420 nm. The photocurrent density of Ag/α-Fe<sub>2</sub>O<sub>3</sub>/TiO<sub>2</sub> (2.59 mA/cm<sup>2</sup>) is
almost 2.5- and 5-fold higher than that of α-Fe<sub>2</sub>O<sub>3</sub>/TiO<sub>2</sub> (1.05 mA/cm<sup>2</sup>) and pristine TiO<sub>2</sub> (0.54 mA/cm<sup>2</sup>), respectively, which can be related
with the plasmonic behavior of Ag and lower band gap of α-Fe<sub>2</sub>O<sub>3</sub>. The results of electron impedance spectroscopy
(EIS) analysis also showed facile charge transfer in the same order
observed using UV–vis spectroscopy. These results demonstrate
the effectiveness of the in situ electrochemical protocol to fabricate
tunable heterostructures for efficient solar-driven water splitting