To investigate the formation of one-dimensional CdS nanowires, we synthesized them by a solvothermal
method in ethylenediamine as a single solvent at different temperatures and times. The sample synthesized
at 160 °C for 72 h had an average diameter of ca. 50 nm and a length of ca. 3−4 μm and hexagonal phase
with high crystallinity. It was revealed that the formation of CdS nanowires followed three-step processes
during the solvothermal synthesis; the seed formation process yielded nanosheets emanating from a mirosphere
followed by the nanorod formation and growth of nanorods to nanowires. The CdS nanowires with higher
crystallinity showed a higher rate of photocatalytic hydrogen production from water containing 0.1 M Na2S
and 0.0 2M Na2SO3 as sacrificial reagents under visible light irradiation (λ ≥ 420 nm). A high and stable
photocurrent generation was also observed from the CdS nanowire film under visible light.
A simple microwave synthesis procedure has been developed for the single-crystalline perovskite nanocubes composed of bismuth ferrite (BiFeO3). Typical nanocubes had sizes ranging from 50to200nm. The single-crystalline nature of nanocubes was confirmed by high resolution transmission electron microscopy and selected area electron diffraction pattern. X-ray diffraction pattern showed the rhombohedral phase with R3c space group. The material showed photoinduced water oxidation activity in both photoelectrochemical and photocatalytic modes. It could become a useful material for photoelectrode and photocatalytic applications.
A new p-type CuNb3O8 polycrystalline photoelectrode was investigated and was determined to have indirect and direct bandgap sizes of 1.26 and 1.47 eV, respectively. The p-type polycrystalline film could be prepared on fluorine-doped tin oxide glass and yielded a cathodic photocurrent under visible-light irradiation (λ > 420 nm) with incident photon-to-current efficiencies of up to ∼6-7% and concomitant hydrogen evolution. A Mott-Schottky analysis yielded a flat band potential of +0.35 V versus RHE (pH = 6.3) and a calculated p-type dopant concentration of ∼7.2 × 10(15) cm(-3). The conduction band energies are found to be negative enough for the reduction of water under visible light irradiation. A hole mobility of ∼145 cm(2)/V·s was obtained from J(I)-V(2) measurements using the Mott-Gurney relation, which is ∼50% higher than that typically found for p-type Cu2O. DFT-based electronic structure calculations were used to probe the atomic and structural origins of the band gap transitions and carrier mobility. Thus, a new p-type semiconductor is discovered for potential applications in solar energy conversion.
The rising significance of producing useful chemical fuels from sunlight has motivated an upsurge of photochemical research, as shown by the growing diversity of chromophores, redox catalysts, and reactivity studies. However, their synergistic integration within artificial photosynthetic systems requires shareable platforms. Early transition-metal oxides have exhibited effective chromophoric/electronic properties across many systems, which has enabled outstanding photocatalytic water splitting efficiencies, but only under ultraviolet irradiation. Semiconducting modifications of these oxides have been investigated that both extend their absorption deep into the visible region and also closely bracket the redox potentials for water splitting and carbon dioxide reduction. Their coupling to surface-anchored molecular catalysts in order to lower kinetic barriers and provide product selectivity is anticipated to lead to studies involving the dynamic interplay of photons, charge carriers, and catalyst turnover.
Barium titanate nanowires synthesized with a surfactant-free hydrothermal method have been characterized by various techniques such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), synchrotron X-ray diffraction, X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. The TEM and SEM analyses show the uniform cylindrical nanowires. The Rietveld refinement with synchrotron X-ray powder diffraction showed that the lattice parameters of cubic and tetragonal phases were a (= b = c) = 4.0134 A and a (= b) = 3.9998 A, c = 4.0303 A, respectively. The final weighted R-factor, R(wp), was 6.75% and the goodness of fit indicator was 1.30. The mass fraction of tetragonal and cubic phases based on the refined scale factor for the two phases were 98.4% and 1.6%, respectively, which clearly show the nanowires are tetragonal. The XPS analysis has shown that as-obtained BaTiO3 nanowires were phase pure. The Raman spectra confirm the tetragonal phase of the BaTiO3 nanowires. The dielectric constant measurement shows the shift in the transition temperature (Tc = 105 degrees C) compared to the bulk transition temperature (Tc = 132 degrees C). The dielectric constant at Tc was 174 measured at 1 kHz frequency.
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.