6 research outputs found
Three-Dimensional CdS-Sensitized Sea Urchin Like TiO<sub>2</sub>‑Ordered Arrays as Efficient Photoelectrochemical Anodes
We demonstrate the fabrication of
a 3D ordered sea urchin like
TiO<sub>2</sub> structure by combining colloidal spheres template,
atomic layer deposition (ALD), and hydrothermal growth method. The
3D sea urchin like TiO<sub>2</sub> arrays as photoanode present improved
photoelectrochemical performance in contrast to 2D TiO<sub>2</sub> hollow microspheres and 1D TiO<sub>2</sub> nanowires arrays. With
CdS quantum dots sensitization, the sea urchin like TiO<sub>2</sub> array photoanode yields a photocurrent of 5.4 mA cm<sup>–2</sup> at 0 V vs Ag/AgCl. The performance improvement is attributed to
the increased specific surface area and porosity, light trapping effect
by multiscattering of the hierarchical structure, as well as direct
charge transportation paths from the nanorods to the microspheres
Density, Viscosity, Refractive Index, and Surface Tension for Six Binary Systems of Adamantane Derivatives with 1‑Heptanol and Cyclohexylmethanol
Measurements
on densities (ρ), viscosities (η), and
refractive indices (<i>n</i><sub>D</sub>) from (293.15 to
333.15) K and at 0.1 MPa along with the surface tensions (γ)
at 298.15 K and 0.1 MPa for binary mixtures of 1,3-dimethyladamantane
(1,3-DMA), 1-ethyladamantane (1-EA), and 1,3,5-trimethyladamantane
(1,3,5-TMA) with 1-heptanol or cyclohexylmethanol have been carried
out over the entire composition range. The experimental data are used
to calculate the excess molar volumes (<i>V</i><sub>m</sub><sup>E</sup>), viscosity deviations (Δη), molar refraction
deviations (Δ<sub>Φ</sub><i>R</i>), and surface
tension deviations (Δγ). The <i>V</i><sub>m</sub><sup>E</sup>, Δη, Δ<sub>Φ</sub><i>R</i>, and Δγ values have been fitted to the Redlich–Kister
polynomial equation. From these excess or deviation functions, the
molecular interactions and nonideality of the binary systems are discussed.
The results are expected to provide fundamental data for understanding
the properties of adamantane derivatives as potential components and
the composition optimization of new high energy-density hydrocarbon
fuels
Thermal Stability and Decomposition Kinetics of 1,3-Dimethyladamantane
For
a comprehensive understanding of the properties of 1,3-dimethyladamantane
(1,3-DMA) as a candidate of high energy-density hydrocarbon fuels,
thermal stability of 1,3-DMA under different conditions is investigated.
The thermal decomposition kinetics in the batch reactor between 693
and 743 K has been determined, with the rate constants ranging from
4.00 × 10<sup>–7</sup> s<sup>–1</sup> at 693 K
to 35.19 × 10<sup>–7</sup> s<sup>–1</sup> at 743
K, along with the Arrhenius parameters of <i>A</i> = 2.39
× 10<sup>7</sup> s<sup>–1</sup> and activation energy <i>E</i><sub>a</sub> = 183 kJ·mol<sup>–1</sup>. The
rate constants for the thermal decomposition of 1,3-DMA are observed
to be smaller than those of some typical model fuels, decalin, propylcyclohexane,
butylcylohexane, and <i>n</i>-dodecane, demonstrating that
the thermal stability of 1,3-DMA is satisfactory. The thermal decomposition
of 1,3-DMA in the flowing reactor at temperatures from 873 to 973
K and pressures from 0.1 to 5.0 MPa is further performed. It can be
observed that the conversion of 1,3-DMA and the yield of gaseous products
increase clearly with the rise of temperature or pressure. The residence
time is the main factor for the change of decomposition depth. Methane
and hydrogen are the major gaseous products that are produced through
demethylation and dehydrogenation. In the liquid residues, toluene
and xylene are observed and quantified by GC-MS, HPLC, and NMR as
the main aromatics produced. On the basis of component analysis, a
hypothetical mechanism of thermal decomposition of 1,3-DMA is proposed
to explain the product distribution. It is shown that the different
products are mainly obtained through a combination of isomerization,
hydrogen transfer, β-scission, and dehydrogenation. The results
are expected to provide experimental information for the search of
new high energy-density hydrocarbon fuels
Density, Viscosity, Surface Tension, and Refractive Index for Binary Mixtures of 1,3-Dimethyladamantane with Four C<sub>10</sub> Alkanes
For
a comprehensive understanding of the properties of 1,3-dimethyladamantane
(1,3-DMA) as a new potential candidate of high energy-density hydrocarbon
fuels, densities, viscosities, surface tensions, and refractive indices
for binary mixtures of 1,3-DMA with each of four C<sub>10</sub> alkanes, <i>n</i>-decane, butylcyclohexane, decalin, and <i>exo</i>-tetrahydrodicyclopentadiene (JP-10), are determined over the whole
composition range at different temperatures ranging from (293.15 to
363.15) K and atmospheric pressure (0.1 MPa). The excess molar volume
(<i>V</i><sub>m</sub><sup>E</sup>), the viscosity deviation
(Δη), the surface tension deviation (Δγ),
and the refractive index deviation (Δ<i>n</i><sub>D</sub>) for these binary systems are calculated. All of the <i>V</i><sub>m</sub><sup>E</sup> values are negative over the whole
composition range for these systems, and they show slight changes
against the temperature. The Δη values for the systems
except 1,3-DMA + JP-10 are negative, and the absolute values decrease
obviously with rising temperature. The Δγ gives clearly
negative values for the system of 1,3-DMA + <i>n</i>-decane
and shows small values near zero for the other systems. Negligible
values of Δ<i>n</i><sub>D</sub> indicate that the
refractive indices show nearly linear additions from those of two
components for the binary mixtures. The results could provide important
reference information for the development and performance of new high
energy-density hydrocarbon fuels
Thermal Decomposition Kinetics and Mechanism of 1,1′-Bicyclohexyl
Thermal
decomposition of 1,1′-bicyclohexyl, a potential
surrogate component of high-density hydrocarbon fuels, was performed
in a batch-type reactor to investigate its thermal stability. A first-order
kinetic equation is supposed to correlate the decomposition process,
and the apparent rate constants, ranging from 0.0223 h<sup>–1</sup> at 683 K to 0.1979 h<sup>–1</sup> at 713 K, are determined.
The Arrhenius parameters are determined with the pre-exponential factor <i>A</i> = 6.22 × 10<sup>20</sup> h<sup>–1</sup> and
the activation energy <i>E</i><sub>a</sub> = 293 kJ·mol<sup>–1</sup>. Compared with four typical hydrocarbon compounds,
the thermal stability trend is observed in the order of <i>n</i>-dodecane ≈ 1,3,5-triisopropylcyclohexane > bicyclohexyl
> <i>n</i>-propylcyclohexane > decalin. Cyclohexane
and cyclohexene
are found to be the primary products due to the relatively low energy
of the C–C bond connecting the two cyclohexyl rings. Bicyclohexyl
decomposes into cyclohexane and cyclohexene equivalently at the beginning
of the reaction. A probable mechanism on the basis of quantum calculation
and GC-MS analyses for the decomposition of bicyclohexyl is proposed
to explain the product distribution. It is shown that the formation
of decomposition products is mainly obtained through hydrogen transfer, β-scission,
isomerization, or dehydrogenation
DataSheet1_Direct preparation of solid carbon dots by pyrolysis of collagen waste and their applications in fluorescent sensing and imaging.DOCX
The fluorescent carbon dots (CDs) have found their extensive applications in sensing, bioimaging, and photoelectronic devices. In general terms, the synthesis of CDs is straight-forward, though their subsequent purification can be laborious. Therefore, there is a need for easier ways to generate solid CDs with a high conversion yield. Herein, we used collagen waste as a carbon source in producing solid CDs through a calcination procedure without additional chemical decomposition treatment of the raw material. Considering a mass of acid has destroyed the original protein macromolecules into the assembled structure with amino acids and peptide chains in the commercial extraction procedure of collagen product. The residual tissues were assembled with weak intermolecular interactions, which would easily undergo dehydration, polymerization, and carbonization during the heat treatment to produce solid CDs directly. The calcination parameters were surveyed to give the highest conversion yield at 78%, which occurred at 300°C for 2 h. N and S atomic doping CDs (N-CDs and S-CDs) were synthesized at a similar process except for immersion of the collagen waste in sulfuric acid or nitric acid in advance. Further experiments suggested the prepared CDs can serve as an excellent sensor platform for Fe3+ in an acid medium with high anti-interference. The cytotoxicity assays confirmed the biosafety and biocompatibility of the CDs, suggesting potential applications in bioimaging. This work provides a new avenue for preparing solid CDs with high conversion yield.</p