The behavior of hydrothermally synthesized hematite nanorods prepared on spin coated seed layers

Herein we report on the effect of varied spin-coated seed layer concentrations of Iron (III) chloride hexahydrate (FeCl3.6H2O) on the photoelectrochemical performance of hydrothermally synthesized hematite nanorods. The seed layers were prepared from 0.05, 0.07, 0.09, 0.11, and 0.13 M concentrations of FeCl3.6H2O. The nanorods were vertically aligned with slight inclinations over the seed layers with the two lowest molar concentrations (0.05 and 0.07 M) of FeCl3.6H2O. A further increase in seed layer concentrations transformed the nanorods as they grew over others and agglomerated into clusters. Structural analysis using X-ray diffraction (XRD) and Raman spectroscopy demonstrated uniform hematite crystalline peaks for all the samples. All samples absorbed highly in the visible region within an onset absorption edge wavelength ranging from 624 to 675 nm. Overall, the nanorods synthesized over the lowest seed layer concentration of 0.05 M of FeCl3.6H2O exhibited the highest photocurrent density of 0.077 mA/cm2 at 1.5 V vs. reversible hydrogen electrode. The results obtained provide important information about the structural, optical, and photoelectrochemical properties of hematite nanorods synthesized over varied seed layer concentrations. This is a key contribution in understanding and enhancing the hematite nanorods performance for photocatalytic applications.

Preparation and Electrochemical Performance of Three-Dimensional Vertically Aligned Graphene by Unidirectional Freezing Method

Three-dimensional vertically aligned graphene (3DVAG) was prepared by a unidirectional freezing method, and its electrochemical performances were evaluated as electrode materials for zinc−ion hybrid supercapacitors (ZHSCs). The prepared 3DVAG has a vertically ordered channel structure with a diameter of about 20−30 μm and a length stretching about hundreds of microns. Compared with the random structure of reduced graphene oxide (3DrGO), the vertical structure of 3DVAG in a three−electrode system showed higher specific capacitance, faster ion diffusion, and better rate performance. The specific capacitance of 3DVAG reached 66.6 F·g−1 and the rate performance reached 92.2%. The constructed 3DVAG zinc−ion hybrid supercapacitor also showed excellent electrochemical performance. It showed good capacitance retention up to 94.6% after 3000 cycles at the current density of 2 A·g−1.

High-permeability vacuum membrane distillation utilizing mechanically compressed carbon nanotube membranes

High-permeable vacuum membrane distillation by applying vertically aligned carbon nanotube for the first time.

DEVELOPMENT OF A BROADBAND ELECTROMAGNETIC RADIATION ABSORBER BASED ON MULTIWALL CARBON NANOTUBES AND ITS APPLICATION IN BOLOMETRIC RECEIVERS

This work is devoted to the development of a technique for obtaining an array of multi-walled vertically aligned carbon nanotubes (VACNT) with a thickness of up to 120 μm on Si/Al2O3/Fe substrates and to the study of their absorbing properties in the THz spectral region, as well as to the assessment of their prospects as a broadband THz radiation absorber based on calculations of the spectral dependence of absorption coefficient for traditional and inverted-type bolometric devices. It is shown that the absorption of the VACNT array transferred onto the Revalpha polymer substrate reaches 70–80% in the wavelength range of 40–200 µm. Calculations show that traditional bolometers with an absorber based on VACNT have the best sensitivity at wavelengths less than 100 μm, and inverted bolometers also having a VACNT layer have the best sensitivity at wavelengths exceeding 50 μm, which makes them complementary to each other.