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Comonomers vinylimidazole, methyl acrylate, and acrylic acid were added to acrylonitrile to synthesize two polymers, poly(acrylonitrile-co-1-vinylimidazole) and poly(acrylonitrile-co-N-vinylimidazole-co-methyl acrylate-co-acrylic acid), with the goal of enhancing their melt processability for their use as carbon fibers. The two polymers were melt-extruded, but the as-spun filaments were brittle. Therefore, glycerol was mixed with the polymers to improve their spinnability and drawability. The addition of glycerol to the polyacrylonitrile copolymer and tetrapolymer reduced their melt viscosity, enhanced their melt spinnability, and improved their drawability. When 15 % (w/w) glycerol was added, the melt viscosity of the two polymers was reduced to below 1000 Pa·s at a shear rate of 100 s-1, and the tensile strength of the resulting filaments was high enough for them to be used as precursor filaments for carbon fibers. Furthermore, a draw ratio of over 5.5 was achieved for the melt spun filaments of mixtures of the copolymer and tetrapolymer with 15 % glycerol (w/w) at a temperature of 150 °C.

Zero-dimensional-two-dimensional (0D-2D) hybrid optoelectronic devices have demonstrated high sensitivity and high performance due to the high absorption coefficient of 0D materials with a tunable detection range and a high carrier transport property of 2D materials. However, the reported 0D-2D hybrid devices employ toxic nanomaterials as sensitizing layers, which can limit the practical applications. In this study, we first fabricated the 0D-2D hybrid photodetector using nontoxic InP quantum dots (QDs) as a light-absorbing layer and black phosphorus (BP) as a transport layer. The surface treatment using 1,2-ethanedithiol and thermal treatment were carried out to remove the surface long ligands of colloidal QDs, which can accelerate the charge injection of the photogenerated carriers through the interfaces between InP QDs and BP. The InP QDs/BP hybrid photodetector demonstrates a high responsivity of 1 × 109 A/W and detectivity of 4.5 × 1016 Jones at 0.05 μW cm-2 under 405 nm illumination. The results show that 0D-2D hybrid photodetectors based on III-V semiconducting QD materials can be optimized for high-performance photodetectors.

The synergetic effects of Co oxides on the Ni/CoAl (NCA) catalysts were observed at an optimal molar ratio of Al/Co = 2 (NCA(2)) due to the partial formations of thermally stable spinel CoAl2O4 phases for the steam reforming of propane (SRP). The optimal content of the spinel CoAl2O4 phases on the NCA(2) was responsible for the formation of the relatively active oxophilic metallic Co nanoparticles with a smaller amount of less active NiAl2O4 on the surfaces by preserving the relative amount of metallic Co of 68% and 52% in the reduced and used catalysts, which enhanced the catalytic activity and stability with the largest specific rate of 1.37 C3H8/(Ni + Co)h&minus, 1 among the tested NCA catalysts. The larger or smaller amounts of Co metal on the less active NCA mainly caused the preferential formation of larger aggregated Ni nanoparticles ~16 nm in size due to their weaker interactions, or induced the smaller formations of active metal phases by selectively forming the spinel NiAl2O4 phases with ~60% in the NCA(4), resulting in a fast deactivation.

Four new compounds, phomalichenones A-D (1-4), and seven known compounds (5-11) were isolated from the cultures of an endolichenic fungus Phoma sp. EL002650. Their structures were determined by the analysis of their spectroscopic data (NMR and MS). Compounds 1 and 6 inhibited nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. In addition, compound 1 diminished the protein expression levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), and decreased the mRNA expression levels of pro-inflammatory cytokines, such as tumor necrosis factor-α (TNF-α), interleukin(IL)-1β, and IL-6.

Recently, black phosphorus (BP) with direct band gap exhibited excellent potential for optoelectronic applications because of its high charge carrier mobility and low dark current as well as the variable band gap of 0.3-1.5 eV depending on the number of layers. However, few-layer BP-based phototransistors (photo-FETs) have been limited in sensitivity and wavelength selectivity. To overcome the drawback of these photo-FETs, we studied hybrid photo-FETs combined with the novel properties of the two materials between the channel and sensitizer layers. By combining a strong absorbance of a quantum dot (QD) layer and a two-dimensional layer material with high carrier mobility, the hybrid photo-FETs are expected to produce high-performance photodetectors that can effectively control the responsivity, detectivity, and response time. In this study, we demonstrate that the photogenerated carriers formed from QD sensitizer layers migrate to the BP transport layer with high charge mobility and not only improve the photodetector performance but also enhance the photodoping effect of the BP transport layer with an ambipolar characteristic by electrons transferred from n-type CdSe QDs or holes injected from p-type PbS QDs. The responsivity and detectivity of hybrid BP/0D photo-FETs exhibit 1.16 × 109 A W-1 and 7.53 × 1016 Jones for the BP/CdSe QD photo-FET and 5.36 × 108 A W-1 and 1.89 × 1016 Jones for the BP/PbS QD photo-FET, respectively. The photocurrent rise (τrise) and decay (τdecay) times were τrise = 0.406 s and τdecay = 0.815 s for BP/CdSe QD photo-FET and τrise = 0.576 s and τdecay = 0.773 s for BP/PbS QD photo-FET, respectively.

Effects of the crystalline tungsten carbide (WxC) phases on an ordered mesoporous bimetallic Rh-Mn/WxC, which were prepared by changing carbon source to tungsten (C/W) ratios of the WxC support using a hard-template of an ordered mesoporous SBA-15, were investigated for a direct synthesis of mixed alcohols by CO hydrogenation from syngas. The C/W ratios on the mesoporous Rh-Mn/WxC showed a significantly different catalytic activity, especially on the C 1 - C 3 alcohol productivity. The Rh-Mn/WxC prepared at C/W molar ratio of 10 having a metastable W 2 C main phase (Rh-Mn/WxC(10)) revealed a higher CO conversion of 8.1% and selectivity to higher alcohols of 54.4% compared to other catalysts having a main crystalline phases of WO 3 or WC. The enhanced catalytic activity and selectivity to mixed alcohols on the Rh-Mn/WxC(10) were attributed to the largely exposed smaller active Rh nanoparticles with its stronger interactions with the metastable W 2 C phases. The superior activity was originated from the intimate interactions of Rh nanoparticles with Mn promoter by maintaining proper oxidation states confirmed by surface ratios of the metallic Rh to oxidized Rh n+ species. The stable preservation of the ordered mesoporous structures of the W 2 C phase in the amorphous carbon matrixes significantly altered the chemical states of the small Rh nanoparticles below 2 nm in size by preferentially existing on the outer surfaces of the W 2 C support, which resulted in showing an enhanced productivity of higher C 1 –C 3 alcohols with 171.8 g/(kg cat ·h).

The reduction-oxidation characteristics and proper kinetic models of three different iron ores having respective main phases of FeOOH, Fe 3 O 4 , and Fe 2 O 3 were investigated using an isothermal method. A proposed kinetic model was well satisfied to explain the experimental data for CO 2 activation to CO with a high accuracy. The kinetic data of the different phases of iron ores for its reduction by H 2 and for the oxidation by CO 2 were relatively well described by a simple three-dimensional diffusion model of Jander equation. Activation energies of three different iron ores with the phase of FeOOH, Fe 2 O 3 , and Fe 3 O 4 for the oxidation by CO 2 were found to be 42, 25, and 12 kJ/mol, respectively. Iron ore having a FeOOH phase exhibited a higher redox property by showing a large amount of CO generation through CO 2 activation with an activation energy of 42 kJ/mol and a rate constant of 0.0065 min –1 . The superior activities on the FeOOH were mainly attributed to a large surface area with medium grain size of FeOOH crystallites by forming a thermodynamically stable Fe 3 O 4 phase on the outer surfaces even under the reduction-oxidation reaction cycle.

Heterojunction structures using 2D materials are promising building blocks for electronic and optoelectronic devices. The limitations of conventional silicon photodetectors and energy devices are able to be overcome by exploiting quantum tunneling and adjusting charge balance in 2D p–n and n–n junctions. Enhanced photoresponsivity in 2D heterojunction devices can be obtained with WSe2 and BP as p‐type semiconductors and MoS2 and WS2 as n‐type semiconductors. In this study, the relationship between photocurrent and the charge balance of electrons and holes in van der Waals heterojunctions is investigated. To observe this phenomenon, a p‐WSe2/n‐WS2/n‐MoS2 heterojunction device with both p–n and n–n junctions is fabricated. The device can modulate the charge carrier balance between heterojunction layers to generate photocurrent upon illumination by selectively applying electrostatic doping to a specific layer. Using photocurrent mapping, the operating transition zones for the device is demonstrated, allowing to accurately identify the locations where photocurrent generates. Finally, the origins of flicker and shot noise at the different semiconductor interfaces are analyzed to understand their effect on the photoresponsivity and detectivity of unit active area (2.5 µm2, λ = 405 nm) in the p‐WSe2/n‐WS2/n‐MoS2 heterojunction device.

Prototype FeOx/TiO2 was applied for dehydrogenation of ethane to ethylene and successive CO2 activation to CO for further chemical looping (CL) application. The Fe(5)/TiO2 exhibited a facile redox cyclic activity with an insignificant coke formation and comparable CO2 activation through reduction-oxidation reaction cycles. During the oxidative dehydrogenation of chemical looping (CL-ODH), the Fe nanoparticles (Fe2O3) on the rutile TiO2 were partially transformed to the thermally stable FeTiO3 phases with its lower oxidation state (Fe2+) below 700 °C. However, the formations of Fe2TiO5 phases were found to be less active than the smaller sizes of iron oxides (Fe3+). The thermally stable iron phases with their reversible redox natures between FeTiO3 and Fe2O3 phases were responsible for a stable reduction-oxidation activity. The robust preservation of the partially reduced surface Fe2+ sites with the copresence of the larger Fe2O3 hematite crystallites on the TiO2 was responsible for improving the redox activity and stability.

Two new α-pyrones, dothideopyrones E (1) and F (2), were isolated from a culture of the endolichenic fungus Dothideomycetes sp. EL003334. Their structures were elucidated by spectroscopic data analysis. Their absolute configurations were established by the modified Mosher’s method. Compound 2 inhibited nitric oxide (NO) production with IC50 values of 15.0 ± 2.8 μM in lipopolysaccharide (LPS)-induced BV2 cells. Compound 2 diminished the protein expression levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). Additionally, 2 decreased the mRNA expression levels of pro-inflammatory cytokines, such as tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6.

Synthesized magnetite (Fe3O4) nanoparticles, with an average crystallite size of 8 and 22 nm, were investigated for Fischer–Tropsch synthesis reaction to clarify the effects of iron crystallite size and a potassium promoter. The larger crystallite size of Fe3O4 without the potassium promoter showed an increased CO conversion with a lower selectivity of C5+ and olefinic hydrocarbons. This was mainly attributed to the enhanced reduction degree and an abundance of active edge sites of cube-like morphology. However, a modification of Fe3O4 nanoparticles with the potassium promoter significantly changed the product distribution by increasing C5+ and olefinic hydrocarbons with much higher CO conversions. The enhanced activity on the large crystallite size of K-modified Fe3O4 was mainly attributed to an enhanced secondary reaction of olefins formed on the active iron carbide sites. The positive effect of the potassium promoter was much significant on the larger Fe3O4 nanoparticles due to an abundant presence of potassium promoter on the outer surface of the large Fe3O4 nanoparticles with a bigger inter-particular pore diameter for an easy mass transport.

Two-dimensional black phosphorus (BP) has attracted much attention recently because of its applicability in high-performance electronic and optoelectronic devices. BP field-effect transistors (FETs) with a tunable band gap (0.3-1.5 eV) have demonstrated a high on-off current ratio and a high hole mobility with an ambipolar behavior in global-gated devices. However, local-gated BP FETs for integrated circuits have been reported with only p-type behaviors and a low on-current compared with global-gated BP FETs. Furthermore, BP, which is not stable in air, forms sharp spikes on its surface when exposed to humid air. This phenomenon plays a role in accelerating the degradation of the electrical properties of BP devices, which can occur even within a day. In this paper, we first demonstrate the origin of transport limitations of local-gated BP FETs by comparing the transport properties of hexagonal boron nitride (h-BN)-based device architectures with those of a bottom-gated BP FET on a Si/SiO2 substrate. By using h-BN as passivation and dielectric layers, BP FETs with a low gate operating voltage were fabricated with two different transistor geometries: top-gated and bottom-gated FETs. The highest mobility extracted from the global-gated BP FETs was 249 cm2 V-1 s-1 with a subthreshold swing of 848 mV dec-1.

Black phosphorus (BP) has drawn enormous attention for both intriguing material characteristics and electronic and optoelectronic applications. In spite of excellent advantages for semiconductor device applications, the performance of BP devices is hampered by the formation of phosphorus oxide on the BP surface under ambient conditions. It is thus necessary to resolve the oxygen-induced degradation on the surface of BP to recover the characteristics and stability of the devices. To solve this problem, it is demonstrated that a 1,2-ethanedithiol (EDT) treatment is a simple and effective way to remove the bubbles formed on the BP surface. The device characteristics of the degraded BP field-effect transistor (FET) are completely recovered to the level of the pristine cases by the EDT treatment. The underlying principle of bubble elimination on the BP surface by the EDT treatment is systematically analyzed by density functional theory calculation, atomic force microscopy, and X-ray photoelectron spectroscopy analysis. In addition, the performance of the hexagonal boron nitride-protected BP FET is completely retained without changing device characteristics even when exposed to 30 d or more in air. The EDT-induced recovering effect will allow a new route for the optimization of electronic and optoelectronic devices based on BP.