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Ru and Mo bimetallic catalysts supported on active carbon modified by Phosphotungstic acid (PW) were designed and applied in glycerol hydrogenolysis reaction. The physicochemical properties of the catalysts were characterized and the presence of active sites was investigated from the perspective of the glycerol hydrogenolysis performance. The MoOx is highly selective for the C-O bond cleavage of glycerol molecules, which can reasonably regulate the strong C-C bond cleavage activity of Ru nanoparticles. By using sequential deposition of Ru and Mo supported on mesoporous PW-C, the characterization results show that the combination of isolated low-valence MoOx with metal Ru particles can form “MoOx-Ru-PW”, which provides highly catalytic activity toward C-O bond cleavage, selectively producing more C3 alcohols (mainly 1,2(3)-propanediol). The glycerol conversion of 1 % Mo/Ru/PW-C catalyst was 59.6 %, the selectivity of C3 alcohol was 96.1 %, and the selectivity of propanediol (1,2(3)-propanediol) was 94.9 %. It is noteworthy that the selectivity of 1,3-propanediol reached 20.7 % when the PW was 21.07 % (mass). This study provides experimental evidence for the tandem dehydration and hydrogenation mechanism of the multifunctional Mo/Ru/PW-C catalyst.

Efficient, low-cost methods are required to produce impurity-free bio-oils with minimal nutrient depletion. This study investigated the effect of extraction and pretreatment conditions on the quality of rice bran oil extracted with CO2-expanded hexane. The extraction conditions considered were temperature (20–30 °C), CO2 mole fraction (0.76–0.94), and pressure (4.2–7.0 MPa). The effectiveness of rice bran hot air drying at 80–100 °C for 0.5, 1, 3, and 5 h for lipase inactivation was also studied. The rice bran oil yield and the content of free fatty acids did not depend significantly on the extraction temperature or pressure. The oil solubility increased significantly (p 2 mole fraction of 0.82 at 5.1 MPa and 20 °C, CO2 mole fraction of 0.87 at 5.0 MPa and 25 °C, and CO2 mole fraction of 0.92 at 5.1 MPa and 30 °C, respectively. The most effective pretreatment conditions for rice bran before storage for 10 weeks were 100 °C for 1 h. In addition, the phosphorus concentration of rice bran oil extracted with CO2-expanded hexane at a CO2 mole fraction of 0.88, 5.1 MPa, and 25 °C was ≤ 7.00 ppm, regardless of the pretreatment conditions. Therefore, CO2-expanded hexane extraction can be potentially used to produce impurity-free rice bran oil from both treated and untreated rice bran without refining.

Recently, NiSx based catalysts are promising electrocatalysts for Hydrogen Evolution Reaction (HER) via water electrolysis. In particular, the S/Ni ratio is crucial to improve catalytic activity of NiSx based catalysts. Herein, we synthesized NiSx based catalysts (Ni/S/C) with a tuned S/Ni molar ratio using Ni2+ ions exchange resin. We succeeded in synthesizing Ni/S/C with different S/Ni molar ratio in the range of 0.33–1.72 by changing Ni2+ ions exchange degree. The combination of NiSx and conductive carbon support contributes to high catalytic activity of Ni/S/C on HER. Additionally, Ni/S/C with the S/Ni molar ratio of 0.6 showed the highest onset potential; Ni3S2 is the most active catalyst for HER in NiSx species. Our synthesis method can easily tune the ratio of S/transition metal. This work provides a new direction for the catalyst design of transition metal sulfides and expands their utilization in sustainable catalytic reaction processes.

Mesoporous TiO2 nanospheres that were co-doped with Zn and Sr were synthesized via a simple hydrothermal method. These materials were used as the photoanode in dye-sensitized solar cells (DSSCs). Field-emission electron microscopy showed that the nanospheres were monodisperse and interconnected, while transmission electron microscopy (TEM) showed that the nanospheres were composed of different nanostructures (nanotubes, diamond and sheet-like structures). Scanning TEM showed a homogeneous distribution of Sr, Ti, Zn and O throughout the nanospheres. When the Zn, Sr co-doped mesoporous TiO2 nanospheres were incorporated into DSSCs, a device efficiency of 4.6%, a short circuit photocurrent density of 8.63 mA cm−2 and an open circuit voltage 0.72 V were achieved. The efficiencies of these devices were higher than that of a comparison device (2.9%) that contained TiO2 (P25).

Transparent thin two-dimensional nitrogen-doped graphene (NG) nanosheets coated with Ni- and Cu-doped MoS2 nanosheets (denoted as Ni-Mo-S@NG and Cu-Mo-S@NG, respectively) were synthesized by a simple hydrothermal process. The synthesized samples were coated by a simple spray pyrolysis technique onto fluorine-doped tin oxide substrates. Scanning transmission electron microscopy analysis showed that square-like Ni-Mo-S and hexagonal-like Cu-Mo-S nanosheets were anchored on the surface of NG without aggregation in Ni-Mo-S@NG and Cu-Mo-S@NG, respectively. Raman analysis confirmed the presence of graphene in both samples because of the high G-band intensity. Cyclic voltammetry analysis indicated that Ni-Mo-S@NG possessed superior catalytic activity to Cu-Mo-S@NG as an electrode in dye-sensitized solar cells; the separation between its oxidation and reduction peak currents (Epp) of about 382 mV was smaller than that of a platinum electrode (450 mV). A solar cell with Ni-Mo-S@NG showed a higher open circuit voltage (0.72 ± 0.02 V) and fill factor (0.57 ± 0.04) than those of solar cells with Cu-Mo-S@NG and Pt counter electrodes. The solar cell with Cu-Mo-S@NG showed higher current density and lower Epp (421 mV) than those of an equivalent cell with Pt. The solar cells with Ni-Mo-S@NG and Cu-Mo-S@NG showed power conversion efficiencies of 2.85% and 2.62%, respectively, which were equivalent to that of a cell with a Pt counter electrode (2.41%).

High-capacitance electrochemical supercapacitors are promising devices due to their long-term stability and simple device construction. Unlike available reports on biomass-derived carbon as supercapacitor electrodes, in this paper, we report novel few-layer graphene-like microporous carbon nanosheets obtained from a single biomass precursor, which yield very high specific capacitance. A simple, ultra-low cost, one-step activation-free approach yields few-layer graphene-like microporous carbon nanosheets in the presence of heteroatoms by using ginger root as a biomass precursor. Suitable heteroatom content combined with porous graphene-like carbon nanosheet structure enhances the specific capacitance. The as-prepared carbon nanosheets from ginger roots possessing few-layer graphene-like structures are confirmed by X-ray diffraction and transmission electron microscopy, and the presence of few heteroatoms is confirmed by energy dispersive spectroscopy. The electrochemical measurements reveal that the ginger root-derived carbon electrode exhibits very high specific capacitance of 390 F g−1 at 1 A g−1 of current density. The ginger-derived carbon electrode also has 93.3% capacitance retention until 3500 charge/discharge cycles. This approach indicates great potential to achieve sustainable, low-cost, simple and large-scale production of renewable biomass-derived carbon materials for efficient energy storage applications in the future.

Propane dehydrogenation (PDH) is one of the most promising candidates for the propylene production process to meet the growing demand of propylene for the future. There is an urgent need to develop catalysts for PDH. In this work, we have synthesized high silica Ga-Beta as a new candidate for a catalyst from dealuminated zeolite using the dry gel conversion method. A high silica Ga-Beta catalyst with a Si/Ga ratio of up to 177 can be synthesized. In the PDH reaction, the synthesized Ga-Beta showed the highest propane conversion and the highest propylene yield amongst the Ga-based zeolites. The combination of the Ga species being incorporated into zeolite frameworks, its large microporosity and Bronsted acidity is likely to lead to the excellent catalytic performance of Ga-Beta. Moreover, Ga-Beta with a higher Si/Ga ratio shows a longer catalyst lifetime for the PDH reaction, since the coke deposition rate decreased with the decrease in the amount of acid. This work provides new insights for the PDH reaction over Ga-based zeolite catalysts, and contributes to the progress in the activation and transformation of light alkenes to value-added chemicals.

Ethane dehydroaromatization (EDA) reaction is one of the promising processes to meet the growing demand of aromatics in the future. Zn ion exchanged MFI type aluminosilicate zeolite (Zn/[Al]-MFI) shows high activity on EDA reaction. Zn ion and Bronsted acid derived from Al sites contribute to the high activity on EDA reaction, but excess strong acid sites promote coke formation, leading to rapid deactivation. Herein, we have developed a new synthesis method for Zn ion exchanged MFI type galloaluminosilicate zeolite (Zn/[Ga,Al]-MFI). The coke formation was suppressed by partially substituting Al with Ga since acidity derived from Ga sites are weaker than that derived from Al sites. Zn/[Ga,Al]-MFI was the ideal catalyst to achieve both high catalytic activity and stability on EDA reaction. Our work provides a new design direction of zeolite catalysts on EDA reaction, which can contribute to the progress on the transformation of light alkanes to value-added chemicals.

The infinite dilution binary diffusion coefficients (D12) of acetylferrocene and 1,1′-diacetylferrocene were measured in supercritical carbon dioxide (scCO2) at (313, 353, 363 and 373) K and at pressures from (11 to 26) MPa using the chromatographic impulse response method, and in atmospheric-pressure liquid organic solvents such as acetone at 303 K, methanol at (313, 323, and 333) K and ethanol at (323 and 333) K using the Taylor dispersion method. The D12 values for both solutes were approximately consistent under all of the investigated measurement conditions and were well represented by the hydrodynamic equation, in which D12/T is expressed as a function of solvent viscosity, over almost the entire range of investigated viscosities ranging from the viscosities of liquid organic solvents to that of scCO2. At 313 K and 11 MPa, the D12 values for both the organometallic solutes deviated from the correlation of the D12 values with the solute molecular mass for nonmetallic organic compounds reported in the literature.

In this study, we demonstrate for the first time, a novel and facile one-pot microwave-assisted synthesis of prGO at shorter time period and lower temperature employing hydrochloric acid as an etching agent. Modified porous reduced graphene oxide (prGO) not only avoids the restacking of prGO layers, but also the existence of pores promotes improvement of material transport efficiency. Herein, physical and chemical characterization confirms the presence of macro/mesopores in the obtained prGO without any restacking issue, unlike reported rGO studies. The synergistic effect of the interconnected macro/mesopores provides facile ion transport pathways with the favorable electrolyte contact when compared to the reported rGO studies. In addition, the presence of macropores can shorten the transfer path distance of electrons/ions to the electroactive sites thereby enhancing specific capacitance. As a result, the synthesized prGO shows excellent specific capacitance of 568.5 F g−1 at 1 A g−1 with a remarkable capacity retention after longer charge/discharge cycles. The proposed synthesis approach can be employed to develop prGO based electrode material for various supercapacitor devices.

Zeolite-templated carbons (ZTCs) composed of curved and single-layer graphene frameworks have uniform micropores (ca. 1.2 nm) and high surface areas (~4,000 m2/g). Owing to their outstanding properties originating from the porous structures, ZTCs have been used in many applications. In this work, we synthesized Co/N-doped ZTC (Co/N-ZTC) by complexing Co ion with 2-methylimidazole in Y zeolite to expand further utilization of ZTCs. The obtained Co/N-ZTC has a high surface area (ca. 2,000 m2/g) and single atomic Co species in CoNx moieties, which actually contributes to its excellent catalytic performance on oxygen reduction reaction. This synthetic concept is beneficial to fabricate single atomic transition metals coordinated with heteroatoms in ZTCs, which contributes to the progress of material design of single atomic catalyst–supported porous materials. A part of this work was supported by “Advanced Characterization Nanotechnology Platform, Nanotechnology Platform Program of the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan, Grant Number JPMXP09A20OS0024 at the Research Center for Ultra-High Voltage Electron Microscopy (Nanotechnology Open Facilities) in Osaka University. In particular, Scanning Transmission Electron Microscope measurement was supported by Dr. Kazuhisa Sato.

The diffusion coefficients of chromium(III) acetylacetonate (Cr(acac)3) were measured at infinite dilution in supercritical carbon dioxide and in liquid ethanol. The diffusion measurements in supercritical carbon dioxide were carried out at five different temperatures varying from T = (308.15 to 343.15) K and at pressures up to 40.00 MPa by using the chromatographic impulse response (CIR) method. And the measurements in liquid ethanol were also made by the Taylor dispersion method at five temperatures in the range from T = (299.15 to 333.15) K and 0.10 MPa. The determined diffusion activation energies in supercritical carbon dioxide were Ea = (22.9–11.2) kJ·mol−1 at p = (13.00–35.00) MPa, respectively, and that in liquid ethanol was 15.9 kJ·mol−1 at 0.10 MPa. All the diffusion coefficients of Cr(acac)3 in supercritical and in liquid states can be correlated by the hydrodynamic equation as a function of temperature and fluid viscosity with average absolute relative deviation (AARD) of 4.6% over a wide viscosity range from η = (3.036·10−5 to 1.113·10−3) Pa·s for 85 data points.

This chapter discusses the techniques for determining the diffusion coefficients in Supercritical Fluids. It explains measurement methods, their advantages and disadvantages and the theories of frequent experimental techniques in detail. The Chromatographic Impulse Response (CIR) method is widely used to measure the solubility, retention factor, partial molar volume and diffusion coefficient for gas, liquid and supercritical fluid chromatographies. Lai and Tan have also employed the CIR method with the moment technique to measure the infinite dilution binary diffusion coefficients of ethyl acetate, toluene, phenol and caffeine in supercritical CO2 (SCO2). The Solid Dissolution technique employs a diffusion cell in which the solid solute compressed into a tablet structure. While Nuclear Magnetic Resonance has long been employed for diffusion study, it became truly practical only after recent developments in hardware, pulse sequences and data analysis. This method is employed to measure the diffusion coefficients over a wide range of temperatures and pressures.

Herein, we report a novel, one-step solvothermal assisted thermal decomposition synthesis of nanoflake-nanorod tungsten disulphide (WS

There is an urgent need to develop low cost electrochemical sensors wherein the sensor can be disposed after recording data, thereby eliminating the issue of inaccuracy arising from repeated sensing measurements, which plagues most conventional electrochemical sensors. This work is the first demonstration of a NiSe

The infinite dilution binary diffusion coefficients D12 for aluminum acetylacetonate in supercritical CO2 were determined at 308.15–333.15 K and at 7.80–40.00 MPa by the chromatographic impulse response (CIR) method. And, the diffusion measurements in liquid ethanol were carried out at 300.15–333.15 K and at 0.10 and 30.00 MPa by the Taylor dispersion method. It was found that the D12 values measured in supercritical CO2 show slowing down in the region of near critical point. The determined activation energies of diffusion were 23.0, 13.7, 12.0, 11.3 kJ/mol at 12.00, 20.00, 25.00, 35.00 MPa in supercritical CO2 and 19.1 kJ/mol at 0.10 MPa in liquid ethanol, respectively. All determined 90 diffusion data in this study can be correlated with the equation of D12 [m2/s] = 1.558 × 10−14 T [K] η [Pa s]−0.761 with average absolute relative deviation (AARD) of 5.6% over a wide fluid viscosity range from 2.462 × 10−5 to 1.258 × 10−3 Pa s.

Infinite dilution binary diffusion coefficients (D12) of two dyestuffs, disperse blue 14 (DB14) and disperse orange 11 (DO11), were measured in supercritical CO2 at 310–330 K and up to 35 MPa by the chromatographic impulse response (CIR) method and in liquid methanol and ethanol at 308–328 K and atmospheric pressure by the Taylor dispersion method. The retention factors (k) were also measured by the CIR method. The diffusion coefficients were well represented by a hydrodynamic equation, as a function of temperature and solvent viscosity, over a wide range of solvent viscosity from scCO2 to liquid solvents with average absolute relative deviations (AARDs) of 1.7% and 2.6% for 63 and 93 data points of DB14 and DO11, respectively. The solubility data for the two dyestuffs reported in the literature were well correlated with solute retention factor measured in the present study and solvent density with AARD of 7.05% for DB 14 of 109 data points and that of 15.4% for DO11 of 43 data points.

In this study, we have developed a new method to synthesize mesoporous titanium silicalite-1 (TS-1) with a higher content of active titanium in the framework (more than 5%) than that obtained from the conventional hydrothermal synthesis. The new method combines two methods as follows: (1) a sol-gel method in tetrahydrofuran for the synthesis of TiO2–SiO2 composite with highly dispersed Ti species and (2) a dry gel conversion method for the crystallization to TS-1. This investigation revealed that the dispersion of Ti in the starting materials was quite important to synthesize mesoporous TS-1 with high content of Ti besides dry conversion method. The obtained mesoporous TS-1 with a high content of titanium showed higher catalytic activity in 1-hexene epoxidation than conventional TS-1. This high activity is likely to originate from the high content of titanium in the framework.

The diffusion coefficients of ibuprofen in both liquid and supercritical fluids are presented for the first time. The diffusion values in liquid ethanol were measured by the Taylor dispersion method at temperatures from 298.15 K to 333.15 K and pressures from 0.10 MPa to 30.00 MPa. Those in supercritical CO2 were carried out by the chromatographic impulse response method at 308.15 K–353.15 K and up to 40.00 MPa. The determined diffusion activation energies in supercritical CO2 were Ea =18.6 kJ/mol to 11.0 kJ/mol at P = 15.00 MPa to 35.00 MPa, and those in liquid ethanol were Ea =16.3 kJ/mol to 15.1 kJ/mol at P = 0.10 MPa to 30.00 MPa, respectively. All the diffusion data of ibuprofen in liquid ethanol and in supercritical CO2 were well correlated by the hydrodynamic equation proposed in this study, with an average absolute relative deviation of 2.2 % for 115 data points.

Herein, we report a novel, one-step solvothermal assisted thermal decomposition synthesis of nanoflake-nanorod tungsten disulphide (WS2) nanomaterial and its application for non-enzymatic electrochemical sensing of uric acid (UA) and quercetin. The as-synthesised WS2 was characterized using X-ray diffraction (XRD), Raman spectrometer, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM). SEM analysis revealed the growth of 2D-1D nanoflake-nanorod hybrid nanostructure of 2H phase WS2 with greater defects and metal edges. Under optimized conditions, the WS2 modified glassy carbon electrode (WS2/GCE) facilitated the effective sensing of UA and quercetin which was measured using differential pulse voltammetry (DPV) technique. The sensor exhibited a low limit of detection (LoD) of 1.2 μM, the sensitivity of 312 nA/μM.cm2 for the dynamic range from 5 μM to 1 mM towards UA while an even lower of 2.4 nM and sensitivity of 258 nA/nM cm2 in the dynamic range of 10 nM–50 μM for quercetin. The enhanced sensing ability of the sensor attributed towards the synergetic effect of 2D-1D hybrid structure of WS2, wherein the 2D nanoflakes enhance the electrocatalytic property of WS2 with shorter diffusion length and 1D nanorods offer large surface area which provides greater number of active sites for sensing. Further, the sensor showed a remarkable selectivity towards UA and quercetin in the presence of ascorbic acid (AA), dopamine (DA), sodium (Na+), chloride (Cl-), calcium (Ca2+) and glucose. The sensor was further employed in successful detection of UA and quercetin in the simulated blood serum sample with excellent recovery percentages. The proposed synthesis route can be used to develop WS2 based electrochemical sensing platforms useful for various bioanalytical applications.

Novel 2D Co-Mo-S anchored on nitrogen-doped graphene (NG) nanosheets was synthesized by simple and cost effective one step hydrothermal method. The effect of ethylenediamine (ETA) on morphology and catalytic activity of Co-Mo-S@NG was studied. Transmission electron microscopy image showed that morphology of Co-Mo-S nanorods and nanosheets changed into flower-like nanostructures composed of numerous sheets by ETA. Scanning transmission microscope showed the formation of Co-Mo-S nanoflower on the surface of NG. X-ray photoelectron spectra analysis confirmed the effective doping of nitrogen in graphene and Co-Mo-S. Counter electrode of dye sensitized solar cell was fabricated by simple spray pyrolysis method at 150 °C. Co-Mo-S@NG with ETA showed lower value of separation between anodic peak and cathodic peak (Epp), higher stability and higher current density compared with pure Cu-Mo-S@NG counter electrodes (CE). Co-Mo-S@NG with ETA showed 1.12% efficiency and current value (Jsc) of 7.22 ± 0.5 mA.

Here is presented the first experimental data for the infinite dilution partial molar volumes of ibuprofen in supercritical carbon dioxide. The measurements were carried out by supercritical fluid chromatography using chemically bonded polyethylene glycol and carbon dioxide as stationary and mobile phases, respectively. The chromatographic retentions of ibuprofen at infinite dilution in supercritical carbon dioxide were measured at six supercritical isotherms of 308.15, 313.15, 323.15, 333.15, 343.15 and 353.15 K and at a pressure range of 8.50–40.00 MPa. The partial molar volumes were determined from the partial derivatives of the retention factors with respect to the densities and were in the range of −2.364 × 10−3 to 1.680 × 10−4 m3/mol. A reverse behaviour was observed, where the partial molar volumes decreased monotonically with decreasing pressure from positive to negative values in all temperature regions investigated. It was also found that the infinite dilution partial molar volumes showed a sharp decrease near the critical point of carbon dioxide. The experimental partial molar volumes were correlated with isothermal compressibilities and densities of carbon dioxide. The correlation proposed in this study could predict the experimental data with an average absolute relative deviation of 4.6% for 80 data points, which is better than that previously reported in the literature.

The infinite dilution binary diffusion coefficients D12 of lithium acetylacetonate were measured in supercritical carbon dioxide by the chromatographic impulse response (CIR) method at 308.15–333.15 K and pressures up to 36.00 MPa. The D12 values were also measured in liquid ethanol at 298.15–333.15 K, and at 0.10, 10.00 and 30.00 MPa by the Taylor dispersion method. The effects of temperature, pressure and density of fluid on D12 values were studied. The D12 data increased from 1.140 × 10−9 m2 s−1 in liquid ethanol at 298.15 K and 30.00 MPa to 2.218 × 10−8 m2 s−1 in supercritical carbon dioxide at 333.15 K and 14.00 MPa. It was observed that the D12 data in supercritical carbon dioxide at 15.00, 20.00 and 30.00 MPa can be well correlated as a function of temperature using an Arrhenius type equation, which provided the diffusion activation energies of 17.5, 13.4 and 11.0 kJ mol−1; that in liquid ethanol at 0.10, 10.00, 30.00 MPa gave the diffusion activation energies of 14.0, 14.2 and 13.8 kJ mol−1, respectively. It was found that the proposed correlation based on hydrodynamic approach can well represent all the measured D12 data of lithium acetylacetonate in supercritical carbon dioxide and in liquid ethanol with the average absolute relative deviation (AARD) of 1.7% for 88 data points.

Retention factors for two enantiomers of trans-stilbene oxide, k1 and k2, were measured with a chiral AD-H column using two syringe pumps to feed CO2 and methanol as a co-solvent at various temperatures, pressures and co-solvent mole fractions to determine the effects of these operating conditions on the retention factors. The retention factors k1 and k2 are for the (R,R)- and (S,S)-forms, respectively. When the isothermal compressibilities of a mixture of CO2 and MeOH were lower than 0.01, far from the critical locus of the CO2 and methanol mixture, both retention factors were well expressed with the solvent density and temperature with an average absolute relative deviation of 1-2%. In the vicinity of the critical locus, however, where the isothermal compressibilities were much larger than 0.01, the relationship between retention factor and density was complicated. Both retention factors were proportional to the isothermal compressibility, irrespective of methanol mole fraction at each temperature.

The effects of temperature and density on retention of platinum(II) 2,4-pentanedionate in supercritical fluid chromatography were investigated at temperatures of 308.15-343.15K and pressure range from 8 to 40MPa by the chromatographic impulse response method with curve fitting. The retention factors were utilized to derive the infinite dilution partial molar volumes of platinum(II) 2,4-pentanedionate in supercritical carbon dioxide. The determined partial molar volumes were small and positive at high pressures but exhibited very large and negative values in the highly compressible near critical region of carbon dioxide.

A green method to synthesize the reduced graphene oxide using supercritical fluid has been developed, which is an environmentally friendly and efficient route. The reduced graphene oxide has been examined by X-ray diffraction, Raman spectroscopy. We have also studied the effects of reduction temperatures and supercritical fluids on the electrical properties of reduced graphene oxide. It was found that ethanol has higher reducing capability than CO2at all temperatures (200 - 400°C) examined in this study for graphene oxide reduction. As a result, reduced graphene oxide (6300 S/m) from supercritical ethanol treatment has 5 times as high conductivity as that from supercritical CO2treatment at the reduction temperature of 400°C. This green process is applicable for large scale production of reduced graphene oxides for various practical applications.

Zeolites have been applied in various chemical processes due to their multi-functionality. In practical use of zeolites, their hydrothermal stability is one of the important factors. We focused on the coating with hydrophobic silicalite-1, which is all silica MFI zeolite. In this work, we investigated the hydrothermal stability of ZSM-5 (MFI type aluminosilicate zeolite) coated with silicalite-1 (all silica MFI zeolite) by the combination of steam treatment and NH3 temperature programed desorption (NH3-TPD). The peak area at higher temperature (h-peak area) in NH3-TPD profiles for core-shell MFI zeolite (ZSM-5/s-1) was unchanged even after steam treatment for 8 h in contrast to uncoated ZSM-5. These results strongly indicate that extremely high Si/Al ratio on the external surface coated with silicalite-1 is highly effective for improving the hydrothermal stability; the hydrophobicity of silicalite-1 probably prevents the penetration of steam into Al sites of ZSM-5. This work opens up a new function of the silicalite-1 layer on ZSM-5 other than improvement of shape selectivity.

There is an urgent need to develop low cost electrochemical sensors wherein the sensor can be disposed after recording data, thereby eliminating the issue of inaccuracy arising from repeated sensing measurements, which plagues most conventional electrochemical sensors. This work is the first demonstration of a NiSe2 based disposable, one time use electrochemical glucose sensor in bio-mimicking real samples wherein NiSe2 was hydrothermally grown NiSe2 on a biodegradable cellulose paper. Both physicochemical (x-ray diffraction, x-ray photoelectron spectroscopy, field emission scanning electron microscope) and electrochemical (impedance spectroscopy and cyclic voltammetry (CV)) characterization techniques confirmed the growth and presence of NiSe2 on a cellulose paper. Electrochemical techniques like CV and amperometric (i-t) were utilized for the selective and sensitive oxidation of glucose. The results suggests that the proposed NiSe2 sensor is effective in a linear range of 0.1-1 mM with fast response time (3.9 s), low detection limit (24.8 ± 0.1 μM) and high sensitivity (0.25 A M-1 cm-2) at a potential applied (E app = 0.55 V versus Ag∣AgCl). Prior to the real sample analyses i.e. glucose detection in human urine, the fabricated NiSe2 sensor was tested for selectivity towards glucose in co-existing interferences (dopamine, ascorbic acid, uric acid, urea, sodium chloride, fructose, lactose and cysteine). Finally, glucose in artificial blood serum and urine samples was demonstrated with the fabricated NiSe2 sensor and the results are comparable to the conventional laboratory methods. The present methodology presents a novel possibility towards the design of next generation, affordable point-of-care devices for a broad range of clinical diagnostics.

Binary diffusion coefficients (D12) and retention factors (k) of platinum(II) acetylacetonate at infinitesimal concentration in supercritical (sc) carbon dioxide (CO2) were measured by the chromatographic impulse response method with a poly(ethylene glycol) coated capillary column at temperatures from (308.15 to 343.15) K and pressures from (8.5 to 40.0) MPa, and D12 in liquid ethanol at temperatures from (298.15 to 333.15) K and atmospheric pressure by the Taylor dispersion method. As has been seen for our previously reported data on other metal complexes measured in sc CO2 and organic solvents, the D12 data in sc CO2 and liquid ethanol were represented by a function of temperature and solvent viscosity. The D12 values for metal complexes were not related to the solute molecular weights. The k values in sc CO2 were expressed by a function of temperature and CO2 density.

The optical properties of graphene-based nanomaterials have attracted much recent attention. This article provides an overview of recent advances in the study of linear and nonlinear optical transitions associated mostly with tailored energy bandgaps. In particular, the optical absorption characteristics and photoluminescence emissions due to various induced bandgaps and, in some cases, the formation of graphene quantum dots are highlighted. Nonlinear optical properties of these materials are reviewed with an emphasis on optical limiting through both nonlinear absorption and scattering mechanisms.

The use of chromatographic impulse response (CIR) method with a coated open tubular capillary column has potential advantages in supercritical fluid chromatography. In this review, applications of the CIR method to measuring the thermodynamic properties such as diffusion coefficients, solubilities and partial molar volumes are presented. This survey gives the theoretical backgrounds for the CIR method with linear adsorption and nonlinear adsorption models. Furthermore, the brief theoretical backgrounds for using retention factors to determine solubilities and partial molar volumes are also provided. In addition, the data sources for the diffusion coefficients with an emphasis on the results published after 2004 and for the partial molar volumes in supercritical carbon dioxide are presented.

Polymeric nanocomposites of high thermal conductivities are developed for their significant potential applications in modern electronics, transportation, and space technologies. Among widely studied nanoscale fillers are carbon nanomaterials of superior thermal transport characteristics, whose incorporation into polymeric matrices may result in nanocomposites that exhibit a good combination of processability and thermal conductivity. In this work we prepared specifically exfoliated few-layer graphene nanosheets (GNs), and dispersed them into two different polymeric matrices, the poly(ethylene-vinyl acetate) copolymer (PEVA) and polyimide (PI). The GNs, generally less than 10 nm in thickness according to X-ray and microscopy characterization results, were found to substantially enhance the thermal transport properties in the resulting polymeric nanocomposite films. The same enhancement was also found in the devices fabricated from the nanocomposites, specifically tubes from melt-extrusion, suggesting significant application potentials of the polymeric/GN nanocomposite materials. The ability for the GNs to impart electrical conductivity into the nanocomposite films was also determined, with the results correlated in terms of the percolation theory. The relative enhancement effects of the GNs at different loadings in the nanocomposite films on thermal and electrical transports are highlighted and discussed.

In the preparation of graphene sheets for various studies and applications, the indirect route through the reduction of graphene oxides (GOs) has been widely pursued. Exfoliated GOs are shown to be mostly single-layer sheets in aqueous solution, and they are also demonstrated for conversion to recover some of the properties intrinsic to graphene. Beyond the commonly used thermal annealing and chemical reduction methods, several environmentally friendly conversion strategies have been explored in the literature. Reported here is a method of annealing GOs in supercritical fluids (SCFs, including carbon dioxide and ethanol) at relatively lower temperatures (up to only 300 °C) for their conversion to reduced GOs (rGOs). The characteristic properties of SCFs include low densities (thus low viscosity/high diffusivity) and diminished surface tension, which have found successful applications in extraction and the cleaning of fragile electronic devices, and also found to enable lower-temperature crystallization of amorphous nanomaterials in a fluid-assisted calcination process. In this study the same principles for lower-temperature calcination in SCFs were applied to the conversion of GOs. The rGOs thus obtained were characterized, with their electrical and thermal conductive properties evaluated and correlated with the different processing conditions. The benefits and shortcomings of the SCF processing method are discussed.

Magnesium borate ball of wires, nanowires and petaliforms were prepared via calcination of magnesium borate hydroxide synthesized by hydrothermal route. Results of SEM characterization indicated that the morphology of magnesium borate hydroxide and magnesium borate could be talored via varying reaction temperature, reaction time and water's volume. And pure magnesium borate could be achieved when magnesium borate hydroxide was calcinated at 700°C.

Petaliform magnesium oxide nanomaterials were prepared by which the basic magnesium carbonate made from light burning powder of low grade magnesite were used as precursor. The XRD results indicated that aqueous magnesium carbonate changed to basic magnesium carbonate (4MgCO3•Mg(OH)2•4H2O) when heating temperature reached 95°C, the SEM confirmed that the morpholoZgy of basic magnesium carbonate (4MgCO3•Mg(OH)2•4H2O) were petaliform, after calcinations the magnesium oxide with the same morphologies as precursors’ were obtained, simultaneously , the products with high activity (iodine value of 197mgI2/g).

The solubilities of organometallic complexes in supercritical CO 2 were determined from retention factors measured by the chromatographic impulse response (CIR) method, in which a solute was pulse-injected into a supercritical CO 2 flowing in a polymer coated open capillary column, and the response curve, i.e. time change of solute concentration, was monitored at the exit of the column. The retention factor and binary diffusion coefficient were simultaneously obtained as two parameters so that the fitting error between response curves of solute species measured and calculated was minimized. The validities of the method and the apparatus employed in this study were verified by determining the solubilities of naphthalene, which have extensively been reported in the literature. Then, the solubilities of organometallic complexes such as ferrocene and cobalt (III) acetylacetonate in supercritical CO 2 were determined. The data determined in this study were in good agreement with the literature data. The solubilities were also correlated with the Chrastil equation including the three adjustable parameters.

Infinite dilution binary diffusion coefficients, D12, of ferrocene, 1,1′-dimethylferrocene and ethylferrocene in hexane, cyclohexane and ethanol at 313.2 K and pressures from 0.2 to 19 MPa, in acetonitrile at 298.2–333.2 K and 0.2 MPa, and various metallic acetylacetonate, acac, complexes such as Co(acac)3, Ru(acac)3, Rh(acac)3, Pd(acac)2 and Pt(acac)2 mainly in ethanol at 313.2 K and 0.2 MPa were measured by the Taylor dispersion method. The D12 values in m2 s−1 for the three ferrocenes in the present study and those of ferrocene and 1,1′-dimethylferrocene in supercritical carbon dioxide in our previous studies were represented by the modified hydrodynamic equation over a wide range of viscosity: M0.5D12/T = 1.435 × 10−13η−0.8446 with average absolute relative deviation of 2.40% for 316 data points, where M is the solute molecular weight, T is the temperature in K, η is the solvent viscosity in Pa s. Although the D12 values for the acac complexes were roughly represented by the above hydrodynamic equation, the accuracies were lower because they were dependent on not solute molecular weight but the number of acac ligand in the complex molecules.

Binary diffusion coefficients, D12, of the metal acetylacetonates, palladium(II) acetylacetonate and cobalt(III) acetylacetonate, were measured from 308.2 to 343.2 K over the pressure range from 9 to 40 MPa at infinite dilution in supercritical carbon dioxide using the chromatographic impulse response method. The effects of pressure, temperature, density, and viscosity on D12 values were examined. It was observed that the D12 values of palladium(II) acetylacetonate and cobalt(III) acetylacetonate were larger than those of lipids with similar molecular weights, such as arachidonic acid and monoolein, respectively. Furthermore, the measured D12 data of each metal acetylacetonate were well correlated by the hydrodynamic equation D12/T as a function of carbon dioxide viscosity.

Binary diffusion coefficients D12 and retention factors k of ferrocene and 1,1′-dimethylferrocene at infinite dilution in supercritical (sc) carbon dioxide were measured by the chromatographic impulse response (CIR) method at temperatures from (308.2 to 323.2) K over a pressure range from (8.0 to 40.3) MPa for ferrocene and from (8.2 to 40.1) MPa for 1,1′-dimethylferrocene. The D12 data for ferrocene were also measured by the Taylor dispersion method with two injection procedures of ferrocene: ferrocene dissolved both in sc CO2 and in liquid hexane. The D12 values of ferrocene were not affected by the injection methods and agreed with those measured by the CIR method. As has been seen for various organic compounds measured in our previous reports, the D12 data for both metal complexes were correlated with the hydrodynamic equation D12/T = αηβ, where η is the CO2 viscosity and α and β are the constants determined by each solute. The retention factors were also correlated with CO2 density.

The hydrodynamic equation D / T = αη β , where D is the infinite dilution binary diffusion or self-diffusion coefficient, T is the temperature, η is the fluid viscosity, and α and β are constants, were demonstrated to be effective for predicting both binary diffusion and self-diffusion coefficients in high density fluids, i.e. liquid and supercritical states. When a solute was specified, the correlation well represented both binary diffusion and self-diffusion coefficients, irrespective of solvent over a wide solvent viscosity range. The solute-dependent constants α and β were determined for 12 solutes with average absolute deviation of 6.2% for 1006 data points.