Three-Dimensional CdS-Sensitized Sea Urchin Like TiO₂‑Ordered Arrays as Efficient Photoelectrochemical Anodes

We demonstrate the fabrication of a 3D ordered sea urchin like TiO₂ structure by combining colloidal spheres template, atomic layer deposition (ALD), and hydrothermal growth method. The 3D sea urchin like TiO₂ arrays as photoanode present improved photoelectrochemical performance in contrast to 2D TiO₂ hollow microspheres and 1D TiO₂ nanowires arrays. With CdS quantum dots sensitization, the sea urchin like TiO₂ array photoanode yields a photocurrent of 5.4 mA cm^–2 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>_D) 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>_m^E), viscosity deviations (Δη), molar refraction deviations (Δ_Φ<i>R</i>), and surface tension deviations (Δγ). The <i>V</i>_m^E, Δη, Δ_Φ<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^–7 s^–1 at 693 K to 35.19 × 10^–7 s^–1 at 743 K, along with the Arrhenius parameters of <i>A</i> = 2.39 × 10⁷ s^–1 and activation energy <i>E</i>_a = 183 kJ·mol^–1. 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 C₁₀ 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 C₁₀ 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>_m^E), the viscosity deviation (Δη), the surface tension deviation (Δγ), and the refractive index deviation (Δ<i>n</i>_D) for these binary systems are calculated. All of the <i>V</i>_m^E 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>_D 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^–1 at 683 K to 0.1979 h^–1 at 713 K, are determined. The Arrhenius parameters are determined with the pre-exponential factor <i>A</i> = 6.22 × 10²⁰ h^–1 and the activation energy <i>E</i>_a = 293 kJ·mol^–1. 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