Amount Of H2 Gas Research Articles

Exploring the potential of surface-modified alginate beads for catalytic removal of environmental pollutants and hydrogen gas generation

In this study, hydrogel beads were fabricated using alginate (Algt) polymer containing dispersed nickel phthalocyanine (NTC) nanomaterial. The viscous solution of Algt and NTC was poured dropwise into a divalent Ca2+ ions, resulting in the formation of hydrogel beads known as NTC@Algt-BDs. The surface of the NTC@Algt-BDs was further modified by coating them with different types of metal ions, yielding metal-coated M+/NTC@Algt-BDs. The adsorbed metal ions i.e., Cu+2, Ag+, Ni+2, Co+2, and Fe+3 were subsequently reduced to zero-valent metal nanoparticles (M0) by NaBH4. The prepared beads were characterized using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Initially, M0/NTC@Algt-BDs were examined for the catalytic reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). Among them, Cu0/NTC@Algt-BDs catalyst exhibited the highest reduction rate and therefore, investigated for reduction of different nitrophenols (NPs) and dyes, including 2-nitrophenol (2-NP), 2,6-dinitrophenol (2,6-DNP), methyl orange (MO), potassium ferrocyanide (PFC), congo red (CR), and acridine orange (ArO). The highest reduction rates of 2.019 and 1.394 min−1 were observed for MO and 2-NP, respectively. Furthermore, the fabricated catalysts were employed for the efficient production of H2 gas by NaBH4 methanolysis. Among which the Ag0/NTC@Algt-BDs catalyst showed excellent catalytic production of H2 gas, exhibiting the lowest activation energy (Ea) of 25.169 kJ/mol at ambient temperature. Furthermore, the impact of NaBH4 amount, and catalyst dosage on the reduction of 2-NP and H2 gas production was conducted whereas the effect of temperature on methanolysis of NaBH4 for evolution of H2 gas was studied. The amount of H2 gas was confirmed by GC-TCD system. Additionally, the recyclability of the catalyst was investigated, as it garnered significant research interest.

Effect of Heat Treatment on Structure of Carbon Shell-Encapsulated Pt Nanoparticles for Fuel Cells.

Polymer electrolyte membrane fuel cells (PEMFCs) have attracted much attention as highly efficient, eco-friendly energy conversion devices. However, carbon-supported Pt (Pt/C) catalysts for PEMFCs still have several problems, such as low long-term stability, to be widely commercialized in fuel cell applications. To address the stability issues of Pt/C such as the dissolution, detachment, and agglomeration of Pt nanoparticles under harsh operating conditions, we design an interesting fabrication process to produce a highly active and durable Pt catalyst by introducing a robust carbon shell on the Pt surface. Furthermore, this approach provides insights into how to regulate the carbon shell layer for fuel cell applications. Through the application of an appropriate amount of H2 gas during heat treatment, the carbon shell pores, which are integral to the structure, can be systematically modulated to facilitate oxygen adsorption for the oxygen reduction reaction. Simultaneously, the carbon shell functions as a protective barrier, preventing catalyst degradation. In this regard, we investigate an in-depth analysis of the effects of critical parameters including H2 content and the flow rate of H2/N2 mixed gas during heat treatment to prepare better catalysts.

Effects of CO-dark Gas on Measurements of Molecular Cloud Stability and the Size–Linewidth Relationship

Stars form within molecular clouds, so characterizing the physical states of molecular clouds is key to understanding the process of star formation. Cloud structure and stability are frequently assessed using metrics including the virial parameter and Larson scaling relationships between cloud radius, velocity dispersion, and surface density. Departures from the typical Galactic relationships between these quantities have been observed in low-metallicity environments. The amount of H2 gas in cloud envelopes without corresponding CO emission is expected to be high under these conditions; therefore, this CO-dark gas could plausibly be responsible for the observed variations in cloud properties. We derive simple corrections that can be applied to empirical clump properties (mass, radius, velocity dispersion, surface density, and virial parameter) to account for CO-dark gas in clumps following power-law and Plummer mass density profiles. We find that CO-dark gas is not likely to be the cause of departures from Larson’s relationships in low-metallicity regions, but that virial parameters may be systematically overestimated. We demonstrate that correcting for CO-dark gas is critical for accurately comparing the dynamical state and evolution of molecular clouds across diverse environments.

Growing Properties of Carbon Nanowalls According to the Hydrogen Gas Ratio.

In this study, the growth characteristics of carbon nanowalls (CNWs), which are applied to many devices because of their high aspect ratio and excellent electrical characteristics thanks to their two-dimensional structure, were confirmed by changing the ratio of methane (CH₄) and hydrogen (H₂) therein. In many studies, CNWs were grown using various chemical vapor deposition (CVD) or sputtering methods, with a mixture of CH₄ and H₂ or argon (Ar) gas. To find the suitable rate, 25 sccm CH₄, which is used as the source gas, was first injected into the chamber, and the characteristics were confirmed by changing the amount of H₂ gas from 0 to 50 sccm. Ultrasonically cleaned Si wafer was used as the substrate, and the CNW was grown for 10 minutes at microwave power (1300 W, 600°C) using microwave-plasma-enhanced CVD (MPECVD).

Aqueous lithium-ion battery of Li4Ti5O12/LiMn2O4 using a lithium-ion conductive solid electrolytes separator

This study investigated the electrochemical properties and performance of an aqueous lithium-ion battery of Li4Ti5O12/LiMn2O4 (LTO/LMO) using a lithium-ion conductive solid electrolyte (SE) composed of NASICON-type Li–Al–Ti–P–O glass ceramic as a separator and a high concentration LiCl-based aqueous electrolyte in order to enhance charge-discharge and cycle life performance. The evolution of H2 gas at the LTO anode during charging was found to be kinetically suppressed by using the SE separator and Zn coating on the LTO anode. As a result, the amount of H2 gas was less than 2.6% that of the porous separator. The SE separator enabled the aqueous electrolyte on the LMO cathode and LTO anode sides to maintain an acidic and a basic solution, respectively, which widened the electrochemical window. Aqueous LTO/LMO batteries using the SE separator exhibited an average voltage of 2.4 V and a high anode capacity of 170 mAh g−1 during charge-discharge cycling test at a rate of 1 C between 2.1 and 2.6 V. It was demonstrated that the battery using a Li2SO4-based aqueous electrolyte in the LMO cathode had good cycle performance and maintained a high coulombic efficiency of 99% after 100cycles.

Lioh and Li2CO3 Removal By a Dry Process Using Atmospheric Pressure Plasma

LiOH and Li2CO3 are impurities remaining in NCM (Ni, Co, Mn Oxide) cathode powder in its manufacturing. As the sources of battery swelling, they need to be removed to a very low level from the cathode material. The existing technique for removing these impurities is wet washing with such as water. N2 and NF3 mixed gas from a multi layered DBD (Dielectric Barrier Discharge) plasma can remove the LiOH and Li2CO3 in dry environment. We monitored the reaction product gas coming from the conversion reaction by QMS residual gas analyzer. The O2 and CO2 concentration was increased in the conversion reaction of LiOH and Li2CO3 respectively. The addition of little amount of H2 gas into the mixed gas increased the dissociation rate of the NF3 molecule. In that condition, the O2 concentration was decreased in LiOH conversion whereas the CO2 concentration was steeply increased in Li2CO3 conversion. This plasma process could remove up to 80% of impurities of LiOH and Li2CO3 from 622 NCM powder in just one minute.

Reactivity with water vapor and hydrogen storage capacity of Be2Ti compound

Beryllium intermetallic compounds show a variety of excellent properties such as neutron multiplication, refractory function, hydrogen storage, and superconductivity. Be12M compounds (M = Ti, V, and Zr) have been investigated as neutron multipliers for fusion reactors, while Be17M2 compounds have been explored as refractory materials. Furthermore, Be2Ms are known to have Laves phases, which are characterized by an A2B type compound having high H2 gas storage potential. Because of its low density, the hydrogen properties of Be2Ms have attracted great interest from viewpoints of reactivity with H2O, trap site of hydrogen, and amount of H2 gas in this compound. However, few studies have dealt with Be2M, and its database remains unsatisfactory.Preliminary synthesis of a beryllium intermetallic compound (=Be2Ti) as a hydrogen storage material was conducted to clarify its reactivity with water vapor at high temperatures and high hydrogen storage capacity. X-ray diffraction profiles and electron-probe microanalysis results confirmed that the preliminary synthesis of single-phase Be2Ti by homogenization treatment and plasma sintering was successful. The hydrogen generation rate of Be2Ti by reaction with 1% H2O increased as the test temperature increased. High temperature exposure to H2O led to the formation of TiO2 on the surface. Furthermore, the hydrogen gas storage concentration of Be2Ti, evaluated using the pressure–concentration–temperature curve, was 0.56 wt.% (=0.125 H/M) at 298 K, which is relatively low considering that H2 pressure was increased up to 13 MPa. Based on additional pressure–composition–temperature measurements, it does not appear to have particle size dependence with regard to hydrogen capacity.A simulation based on first-principles calculation indicated the presence of two hydrogen trap sites, tetrahedral and center of triangle with solution energies of −0.52 and −0.05 eV, respectively, implying that the maximum trap site of hydrogen with 5.4 wt.%. This dissimilarity might be attributed to the fact that the Be2Ti sample contained a large fraction of surface oxide layer, which disturbed the surface penetration of hydrogen.

Hydrogen gas sensor based on long-range surface plasmons in lossy palladium film placed on photonic crystal stack

Nanostructured plasmonic H2 gas sensor has been designed and fabricated by palladium nanostructure onto one-dimensional photonic crystal. Our one dimensional photonic crystal has been designed and fabricated to have photonic band gap in visible spectrum and the palladium nanostructure has been designed and constructed as 11nm thin film onto the above mentioned photonic crystal. All of fabrication processes have been done in vacuum chamber by the aid of electron gun and sputtering deposition methods. The ability of the devise as a Hydrogen gas sensor has been examined by recording the long range surface Plasmon resonance in different injection of H2 gas and our results show that this sensor head can be used to sense very little amount of H2 gas in ambient at room temperature. A reversible red shift of the reflectance deep of long range surface Plasmon resonance make this sensor as a good and useful device in medical, safety and energy related materials.

The TEXES Survey for H2Emission from Protoplanetary Disks

We report the results of a search for pure rotational molecular hydrogen emission from the circumstellar environments of young stellar objects with disks using the Texas Echelon Cross Echelle Spectrograph (TEXES) on the NASA Infrared Telescope Facility and the Gemini North Observatory. We searched for mid-infrared H2 emission in the S(1), S(2), and S(4) transitions. Keck/NIRSPEC observations of the H2 S(9) transition were included for some sources as an additional constraint on the gas temperature. We detected H2 emission from 6 of 29 sources observed: AB Aur, DoAr 21, Elias 29, GSS 30 IRS 1, GV Tau N, and HL Tau. Four of the six targets with detected emission are class I sources that show evidence for surrounding material in an envelope in addition to a circumstellar disk. In these cases, we show that accretion shock heating is a plausible excitation mechanism. The detected emission lines are narrow (~10 km/s), centered at the stellar velocity, and spatially unresolved at scales of 0.4 arcsec, which is consistent with origin from a disk at radii 10-50 AU from the star. In cases where we detect multiple emission lines, we derive temperatures > 500 K from ~1 M_earth of gas. Our upper limits for the non-detections place upper limits on the amount of H2 gas with T > 500 K of less than a few Earth masses. Such warm gas temperatures are significantly higher than the equilibrium dust temperatures at these radii, suggesting that the gas is decoupled from the dust in the regions we are studying and that processes such as UV, X-ray, and accretion heating may be important.

Optimized method of producing washers of titanium hydride for plasma gun using occluded hydrogen gas

An optimized way of producing washers of titanium hydride for the application to a plasma gun using the occluded gas is presented. The amount of H2 gas (equivalently, gas pressure p) is entirely preadjusted in a gas reservoir of a simple instrument. The temperature T of a furnace is completely feedback controlled. Data show that when p is the order of 1atm, T needs to be higher than about 450°C in order to successfully produce washers of titanium hydride. Results on compressive strength of the loaded washers suggest that an appropriate ratio of atoms of hydrogen to titanium is less than H:Ti∼0.85:1.

Pulsed laser deposition of hydrogenated amorphous diamond-like carbon films from a polymer target

Hydrogenated amorphous diamond-like carbon (a-DLC:H) films have been prepared by pulsed laser ablation of a polymer target in the presence of hydrogen (H2) gas. The growth rate of these films was found to be highly dependent on the deposition temperature and the amount of H2 gas used during the deposition process. The optical band gap of these a-DLC:H films changed in a wide range (0.25–2.5 eV) with substrate temperature and H2 pressure, and was found to be highly correlated to the ratio of sp3/sp2 in the film. The gap reached a maximum in a temperature range between 100 and 200 °C and had small values at either lower or higher temperatures. With increasing H2 pressure, the band gap increased monotonically and saturated around 0.5 mbar. It was found that the refractive index and the imaginary part of dielectric constant of these a-DLC:H films monotonically increased with decreases in the wavelength of the probing beam. It was also found that these laser derived a-DLC:H films could be made either completely insulating [∼10−11 (Ω cm)−1] or conducting [∼1 (Ω cm)−1] by simply varying the deposition temperature and H2 pressure. Very little photoconduction has been observed in these a-DLC:H films.

Hydrogen-induced platelets in silicon studied by transmission electron microscopy

Abstract The structure of hydrogen-induced platelets (HIPs) in silicon has been examined with conventional transmission electron microscopy (CTEM) and high-resolution transmission electron microscopy (HRTEM). Hrtem was utilized to clarify the atomic structure in which hydrogen atoms are assumed to saturate the broken bonds between adjacent (111) planes. The structural model was refined by introducing a reliability factor in real space for quantitative comparison between experimental and simulated images. Some contrast variations in HRTEM images can be well explained by allowing for atomic ledges on the (111) plane with broken bonds. Furthermore it is found from the strain contrast in a CTEM image that a considerable amount of H2 gas is contained in the open space of the HIP, which results in an internal pressure as large as 1 GPa. The formation process of Hips is discussed.

Measurement of Occluded Gases Released from Uranium-Plutonium Mixed Carbide and Uranium Carbide Fuels

The release of the occluded gases in uranium-plutonium mixed carbide and uranium carbide pellets for irradiation tests were measured successfully using a multipurpose high temperature apparatus. A new type of gas line filter was set up in the gas exhausting line, where the filter could be exchanged easily without plutonium contamination and degassed by heating. The release of the occluded gases in the carbide fuels was measured at 1,473, 1,673 and 1,873 K. At 1,473 K, most of the gases evolved was H2 gas and above this temperature, the oxygen contained in the fuel was released continuously in the form of CO gas. It was shown that the H2 gas was generated by the reaction of the fuel with moisture adsorbed at the fuel surface during storage and the CO gas was released in proportion to its equilibrium pressure of the oxycarbide solid solution. The release of the gases from the fuels scarcely affects the increase of the inner gas pressure of fuel pins since the amount of H2 gas is small, about 100 μl·atm/g-fu...

Measurement of occluded gases released from uranium-plutonium mixed carbide and uranium carbide fuels.

The release of the occluded gases in uranium-plutonium mixed carbide and uranium carbide pellets for irradiation tests were measured successfully using a multipurpose high temperature apparatus. A new type of gas line filter was set up in the gas exhausting line, where the filter could be exchanged easily without plutonium contamination and degassed by heating. The release of the occluded gases in the carbide fuels was measured at 1,473, 1,673 and 1,873 K. At 1,473 K, most of the gases evolved was H2 gas and above this temperature, the oxygen contained in the fuel was released continuously in the form of CO gas. It was shown that the H2 gas was generated by the reaction of the fuel with moisture adsorbed at the fuel surface during storage and the CO gas was released in proportion to its equilibrium pressure of the oxycarbide solid solution. The release of the gases from the fuels scarcely affects the increase of the inner gas pressure of fuel pins since the amount of H2 gas is small, about 100 μl·atm/g-fuel corrected at 273 K and CO gas pressure equilibrated with carbided fuel is only several hundred Pascal.