Effect Of Air Exposure Research Articles

Selective Chemical Response of Transition Metal Dichalcogenides and Metal Dichalcogenides in Ambient Conditions.

To fabricate practical devices based on semiconducting two-dimensional (2D) materials, the source, channel, and drain materials are exposed to ambient air. However, the response of layered 2D materials to air has not been fully elucidated at the molecular level. In the present report, the effects of air exposure on transition metal dichalcogenides (TMD) and metal dichalcogenides (MD) are studied using ultrahigh-vacuum scanning tunneling microscopy (STM). The effects of a 1-day ambient air exposure on MBE-grown WSe2, chemical vapor deposition (CVD)-grown MoS2, and MBE SnSe2 are compared. Both MBE-grown WSe2 and CVD-grown MoS2 display a selective air exposure response at the step edges, consistent with oxidation on WSe2 and adsorption of hydrocarbon on MoS2, while the terraces and domain/grain boundaries of both TMDs are nearly inert to ambient air. Conversely, MBE-grown SnSe2, an MD, is not stable in ambient air. After exposure in ambient air for 1 day, the entire surface of SnSe2 is decomposed to SnOx and SeOx, as seen with X-ray photoelectron spectroscopy. Since the oxidation enthalpy of all three materials is similar, the data is consistent with greater oxidation of SnSe2 being driven by the weak bonding of SnSe2.

Water accelerated transformation of d-limonene induced by ultraviolet irradiation and air exposure

d-Limonene is a fragrant chemical that widely exists in aromatic products. Isotopic labelling of water molecules plus GC–MS and GC-PCI-Q-TOF analyses were used to investigate the influence of water molecules on chemical transformation of d-limonene induced by UV irradiation and air exposure. The results showed that the synergistic effect of UV irradiation, air exposure and water presence could facilitate d-limonene transformation into the limonene oxides: p-mentha-2,8-dienols, hydroperoxides, carveols, l-carvone and carvone oxide. UV irradiation, air exposure, or water alone, however, caused negligible d-limonene transformation. With the aid of isotopic labelling of water and oxygen molecules, it was found that water molecules were split into hydrogen radicals and hydroxyl radicals, and the hydrogen radicals, in particular, promoted the transformation reactions. This study has elucidated the mechanism and factors that influence the transformation of d-limonene, which will benefit industries involved in production and storage of d-limonene-containing products.

Effect of atmospheric control during MA-HIP process on mechanical properties of oxide dispersion-strengthened Cu alloy

In this study, mechanical properties of Dispersion Strengthened (DS)-Cu-Al (aluminum) and Zr (zirconium) alloys, which were fabricated by an MA-HIP method, were investigated for application to the heat sink materials of fusion reactors. The effect of air exposure before the HIP process was studied using a NIFS-Sealing Device. Cu–Al specimen with air exposure before HIP was broken during wire-electrical discharge formation. Cu–Al specimen without air exposure exhibited high fracture strength, but without yielding. Cu–Zr specimen, both with and without the exposure, yielded and exhibits elongation. An increase in yield and tensile strength by approximately 61% and 45%, respectively, were obtained for Cu–Zr specimen by avoiding air exposure. The results showed that Cu–Zr specimen is less susceptible to the atmosphere of the MA-HIP process than Cu–Al.

The effect of air exposure on the crystal structure of oligo-thiophene thin films investigated using in situ X-ray diffraction

The effect of air exposure on the crystal structure of alkyl substituted organic thin film was studied using in situ grazing incidence X-ray diffraction (GIXD) measurements. The GIXD measurements were carried out by scanning the specific qxy region using a two-dimensional area detector and the Soller slit. The a and b axes of the monoclinic unit cell were found to shrink by air exposure. As for the c axis, there was no detectable change caused by air exposure. The shrinking of the a and b axes immediately occurred after exposure to air, and then saturated in six days. The shrinking of the a and b axes by air exposure might affect the transport properties, because shortening between intermolecular distances should promote the hopping of hole carriers.

Efficient, large area organic photovoltaic modules with active layers processed with non-halogenated solvents in air

Organic photovoltaic (OPV) modules with excellent power conversion efficiencies of 4.20% and 5.87% were obtained with blends of novel low bandgap polymers, POD2T-DTBT and PDTBT-alt-TT, respectively, with PCBM as the active layers. Large area polymer:PCBM blend films were deposited by blade coating with high film uniformity, fast processing speed, and low material consumption, without the need for an inert atmosphere. With the requirements of future manufacturing in mind, the effects of air exposure on the active layers and the substitution of chlorinated solvents for polymer processing were investigated. While the decline of Voc due to air exposure was recovered by appropriate treatment of the completed devices, FF and Jsc were significantly affected due to interfacial effects, indicating that air exposure should be limited in duration. Active layers of POD2T-DTBT:PCBM processed with less toxic, non-halogenated mixed solvents, comprising non-polar o-xylene with small amounts of polar additive, showed a fine, interpenetrating nanofibrous network that facilitates charge transport in bulk heterojunction photovoltaic cells. The performance of POD2T-DTBT:PCBM photovoltaic cells and modules processed with the new ink formulations were on par with that obtained with chlorinated solvents, with the modules exhibiting impressive power conversion efficiencies above 4%. The results indicated that POD2T-DTBT was an outstanding candidate for future OPV production due to its high performance, processibility in different ink formulations and compatibility with the large area coating techniques.

Effects of Air Exposure and Re-Submersion on Oxidative Stress of Marine Gastropod, Babylonia areolata

The effects of air exposure on the antioxidant capacity of marine gastropod, Babylonia areolata, were evaluated. Superoxide dismutase (SOD) activity, malondialdehyde (MDA) content, and total antioxidant capacity (T-AOC) levels in the muscle and hepatopancreas in B. areolata were measured after air exposure and re-submersion. Results showed that SOD activity minimally increased in the hepatopancreas and muscle, after air exposure for 4h. SOD activity in the hepatopancreas was lower than the normal level after 20 h of air exposure and air exposure followed by 4 h of re-submersion. T-AOC levels in the hepatopancreas and muscle of B. areolata decreased significantly (P<0.05) following the period of air exposure. MDA content in the hepatopancreas of B. areolata subjected to air exposure for 24 and 28 h was significantly higher than the normal level. SOD activity in the hepatopancreas and T- AOC level in the hepatopancreas and muscle of B. areolata recovered to the normal level after 12 h of air exposure followed by 8 h of re-submersion. Air exposure can cause oxidative damage to B. areolata. The antioxidative system can be restored after air exposure for less than 12 h followed by re-submersion for 8 h.

Effects of Air Exposure and Re-Submersion on Oxidative Stress of Marine Gastropod, Babylonia areolata

The effects of air exposure on the antioxidant capacity of marine gastropod, Babylonia areolata, were evaluated. Superoxide dismutase (SOD) activity, malondialdehyde (MDA) content, and total antioxidant capacity (T-AOC) levels in the muscle and hepatopancreas in B. areolata were measured after air exposure and re-submersion. Results showed that SOD activity minimally increased in the hepatopancreas and muscle, after air exposure for 4h. SOD activity in the hepatopancreas was lower than the normal level after 20 h of air exposure and air exposure followed by 4 h of re-submersion. T-AOC levels in the hepatopancreas and muscle of B. areolata decreased significantly (P<0.05) following the period of air exposure. MDA content in the hepatopancreas of B. areolata subjected to air exposure for 24 and 28 h was significantly higher than the normal level. SOD activity in the hepatopancreas and T- AOC level in the hepatopancreas and muscle of B. areolata recovered to the normal level after 12 h of air exposure followed by 8 h of re-submersion. Air exposure can cause oxidative damage to B. areolata. The antioxidative system can be restored after air exposure for less than 12 h followed by re-submersion for 8 h.

The combined effects of silicon dioxide nanoparticles and cold air exposure on the metabolism and inflammatory responses in white adipocytes.

The potential hazard of nanoparticles (NPs) from air pollution has attracted widespread attention. Though the toxicology of NPs has been intensively studied, few works have been reported on the combined effect of silicon dioxide (SiO2) NPs and cold air exposure at the cellular level. Herein, we evaluated the combined effect of SiO2 NPs and cold exposure on metabolism and the inflammatory responses in white adipocytes by qRT-PCR in vitro. After SiO2 NP or cold exposure, there were significant changes in the expressions of adipogenic genes and proinflammatory cytokine genes in white adipocytes. The mRNA levels of IL-6, IL-8, TNF-α and IL-1β were upregulated by SiO2 NP or cold exposure, and more so in the combined group. The expressions of the proinflammatory cytokine genes IL-6, IL-8, TNF-α and IL-1β increased highly significantly (P < 0.01) in the SiO2 NP alone group and the combined group, compared with the control. The expressions of the cold group tended to be upregulated significantly compared with the control in IL-6 (P < 0.01) and IL-8 (P < 0.05). The results demonstrated that there was antagonistic effect between SiO2 NPs and cold air on the plasticity and metabolism in white adipocytes, where the main effect of cold air on the plasticity and metabolism was significant (P < 0.05). However, there was a synergistic effect between SiO2 NPs and cold air on the toxic effects in white adipocytes, in which the main effect of SiO2 NPs on the toxic effects was significant (P < 0.05). In conclusion, SiO2 NPs combined with cold exposure induced a stronger inflammatory response and influenced the plasticity and metabolism in white adipocytes, accompanied by more serious health hazards.

Impact of air exposure on the photobiology and biochemical profile of an aggressive intertidal competitor, the zoanthid Palythoa caribaeorum

The colonization of intertidal habitats is a challenging process. During low tide, many photosynthetic organisms, including symbiotic zoanthids, can be partially exposed to air eliciting significant physiological impairments, which may ultimately dictate the rate of colonization in such environments. Within this context, the present study aims to investigate, for the first time, the effects of air exposure on the fatty acid (FA) content and photobiological parameters of Palythoa caribaeorum, by comparing emerged and immersed polyps, within the same colony, during low tide. Tidal environment did not significantly affect FA percentages, but polyps that were emerged showed lower FA content than the immersed ones. Saturated FA fraction contributed the most to those dissimilarities, followed by the highly unsaturated and polyunsaturated FA fractions. Concomitantly, polyps that were permanently immersed displayed significantly higher values of the maximum quantum yield of photosystem II (F v/F m) when compared with emerged polyps. An opposite pattern was observed regarding the indices derived from the rapid light-response curves of relative electron transport rate (α, ETRmax and E k). We argue that FA differences within each colony seem to be a consequence of impairments in carbon production with photoautotrophic origin. Our findings also suggest that emerged polyps display higher efficiency in responding to rapid light fluctuation, which seems to be a peculiar adaptation to these challenging environments. Thus, in addition to its morphological plasticity, P. caribaeorum seems to display a large trophic plasticity that may be linked with the aggressive competitive nature for vital resources in such tidal habitats and widespread distribution.

Effects of Air Exposure on Postrelease Mortality Rates of White Marlin Caught in the U.S. Offshore Recreational Fishery

AbstractWhite Marlin Kajikia albida are targeted by recreational fisheries in tropical and subtropical waters of the Atlantic Ocean. Off the U.S. East Coast, the vast majority of White Marlin are released after capture. Federal regulations prohibit anglers from removing a White Marlin from the water unless the fish is to be retained; however, numerous photographs of anglers holding White Marlin out of the water are posted on the Internet each summer, demonstrating that there is considerable noncompliance with this management measure. To better understand the effect of air exposure on postrelease survival of White Marlin, we attached pop‐up satellite archival tags (PSATs; programmed to release after 30 d) to individuals that were caught on natural baits rigged with circle hooks and that were removed from the water for a period of 1 min (n = 6 fish), 3 min (n = 5 fish), or 5 min (n = 7 fish). We compared our results with those from a previous study in which PSATs were used to follow the fates of 59 White Marlin that were caught on circle hooks but not removed from the water. The proportion of postrelease mortalities increased with air exposure duration; the overall rate of postrelease mortality was significantly higher for White Marlin that were subjected to air exposure (33.3%) than for those that remained in the water (1.7%). These data provide strong support for the current U.S. regulation prohibiting the removal of a White Marlin from the water if the fish is to be released. Effective communication of the deleterious effects of air exposure on White Marlin should help to deter the practice of removing fish from the water among members of the recreational angling community, which has been supportive of other conservation measures for this species.Received January 13, 2016; accepted June 15, 2016 Published online September 30, 2016

Ultralight or Heavyweight? The Interactive Effects of Gear Strength and Air Exposure on Reflex Impairment in Largemouth Bass

AbstractAlthough much is known about the factors that influence the effects of catch‐and‐release angling on fish condition and survival, relatively little is known about the effects of fishing gear strength on fight time and, hence, fish condition. Moreover, little is known about how gear strength and fight time interact with air exposure duration to ultimately influence the level of exhaustion experienced by fish at time of release. Here we systematically varied fishing gear strength (ultralight versus medium‐heavy) and air exposure duration (0 versus 120 s) when targeting Largemouth Bass Micropterus salmoides. We relied on reflex impairment (using five different reflexes) as a real‐time indicator of fish condition. Largemouth Bass fight durations were highly variable between fishing gear types and across fish sizes. Largemouth Bass captured on ultralight fishing gear experienced longer fight times, and there was a stronger positive relationship between fish length and fight time than for those captured on heavier fishing gear. However, fish captured using ultralight gear were easier to handle upon landing and thus experienced shorter hook removal times, which may result in less air exposure in actual angling scenarios. Fish captured with ultralight gear had significantly higher reflex impairment than those captured with heavy gear with no air exposure, while fish captured with both gear types had similarly high reflex impairment when exposed to the air. These results indicate that gear strength does influence the level of exhaustion experienced by Largemouth Bass. However, fish that are landed quickly are so vigorous that handling and hook removal are challenging. We submit that there is likely a compromise where neither ultralight nor ultraheavy gear (always relative to the size and species targeted) is appropriate. Moreover, our findings emphasize the importance of minimizing air exposure, particularly for fish that are exhausted already from a protracted fight.Received December 29, 2015; accepted June 24, 2016 Published online September 30, 2016

Understanding of air influenced poly (3-hexylthiophene) film characteristics in a transistor structure

ABSTRACTThis study presents the air influenced electrical properties of poly (3-hexylthiophene) (P3HT) film in a transistor structure. In order to observe the effect of air exposure on P3HT films, the current–voltage characteristics of P3HT-based organic thin-film transistors (OTFTs) were obtained by increasing the air-exposure time. Upon increasing the air exposure time up to 92 h, the drain current in the saturation region increased, and a positive shift of the threshold voltage was observed. On the other hand, a decrease in the drain current and a negative shift of the threshold voltage were observed after 92 h. A simple theoretical approximation based on carrier doping and scattering effect describes the relationship between electrical performance of P3HT films and air exposure time.

Effects of air exposure, temperature and additives on fermentation characteristics, yeast count, aerobic stability and volatile organic compounds in corn silage.

Ensiling conditions strongly influence fermentation characteristics, yeast count, and aerobic stability. Numerous volatile organic compounds including esters are produced, which may negatively affect feed intake and animal performance and air quality. In addition to a farm survey, 3 laboratory experiments were carried out to study the effects of air (by delayed sealing or by air infiltration during anaerobic storage), temperature (20 and 35°C), and various types of additives [blends of either sodium benzoate and sodium propionate (SBSP) or of sodium benzoate and potassium sorbate (SBPS); buffered mixture of formic and propionic acids (FAPA); homofermentative inoculant (LAB)]. After additive treatment, chopped whole corn plants were packed into 1.5-L glass jars and stored for several months. For treatments with air infiltration, glass jars with holes in the lid and body were used. The farm survey in 2009 revealed large variation in lactate, acetate, ethanol, n-propanol, and 1,2-propanediol concentrations. Whereas ethyl esters were detected in all silages, the mean ethyl lactate concentrations were higher than those for ethyl acetate (474 vs. 38mg/kg of dry matter). In the ensiling experiments, few unequivocal effects of the tested factors on the analyzed parameters were observed due to many interactions. Delayed ensiling without additives decreased lactic acid production but, in one trial, increased acetic acid and had no effect on ethanol. The effect of delayed sealing on yeast counts and aerobic stability differed widely among experiments. Air infiltration during fermentation tested in one trial did not alter lactic acid production, but resulted in more acetic acid in delayed and more ethanol than in promptly sealed untreated silages. Greater ethanol production was associated with increased yeast numbers. Storage at high temperature resulted in lower lactic acid and n-propanol, and a trend toward reduced ethanol production was observed. The additive FAPA consistently caused increased ethanol and reduced n-propanol levels with no effect on yeast counts and aerobic stability. When the additives SBSP and SBPS decreased n-propanol and ethanol, reduced yeast counts were also found. Ethyl ester formation was strongly correlated with those of ethanol and to a lesser degree with those of the respective acid.

Synthesis and Evaluation of NaMPO4 (M=Fe, Mn, Co) Framework Polyanion Cathodes for Sodium-Ion Batteries (SIB)

Polyanion compounds are attractive for use as cathode materials because they generally have higher potentials for a given Mn+/(n+1)+ redox couple in comparison to the oxide analogue.1 In addition, the strong bonding within the polyanion group provides similar safety characteristics to oxides even though they exhibit higher working potentials.2 The phospho-olivine LiFePO4 has been thoroughly investigated as a cathode material for use in lithium-ion batteries since its introduction in 1997.3 It has been determined that NaMPO4 (M = Fe and Mn) compounds prefer the electrochemically inactive maricite structure and not the olivine structure when using conventional synthesis methods,4 which has left the research community seeking unorthodox methods to access the olivine phase.5 , 6 Herein we report on a NaCoPO4 (NCP) polymorph (Red-phase) that has previously only been observed as an impurity while attempting to synthesize other polymorphs.7 The Red-phase was synthesized by a microwave-assisted solvothermal process using tetraethylene glycol as the solvent. Ex-situ XRD and XANES measurements indicate that during cycling the structure undergoes reversible changes and the Co2+/3+ redox couple is partially active near 4.4 V vs. Na. The silicate family of cathode materials is rich in polymorphism8 and has also been thoroughly investigated for use in lithium-ion batteries. Among the polymorphs investigated is Pn­-Li2MnSiO4 9 that was accessed by ion-exchange of the parent Pn­-Na2MnSiO4 compound. Yet, minimal work has been reported on the sodium analogue.9 , 10 Considering the air sensitivity reported of the lithium version,11 herein we report preliminary results on the effect of air exposure on the electrochemistry of Pn­-Na2MnSiO4. § cjohnson@anl.gov Acknowledgements Work supported by U. S. DOE, Office of Science under Contract No. DE-AC02-06CH11357. We also thank the Argonne LDRD program office for additional support.

Oxygen-related photoluminescence quenching in selectively grown GaN nanocolumns: Dependence on diameter

This work reports on the effects of air exposure on the photoluminescence intensity of GaN nanocolumns, with diameters ranging from below 40nm up to around 230nm, grown selectively on GaN/sapphire and GaN/Si(111). The high control of dimensions provided by selective area growth epitaxy allowed for a better study of the relationship between the observed phenomena, namely the photoluminescence intensity quenching due to oxygen photo-adsorption, and the nanocolumns properties (morphology and dimensions). For nanocolumns with diameters below 120nm and lengths of about 300nm, photoluminescence intensity dropped by more than 90% of the initial value, while for shorter nanocolumns a reduced drop value was found.

Scanning Tunneling Microscopy and Spectroscopy of Air Exposure Effects on Molecular Beam Epitaxy Grown WSe2 Monolayers and Bilayers.

The effect of air exposure on 2H-WSe2/HOPG is determined via scanning tunneling microscopy (STM). WSe2 was grown by molecular beam epitaxy on highly oriented pyrolytic graphite (HOPG), and afterward, a Se adlayer was deposited in situ on WSe2/HOPG to prevent unintentional oxidation during transferring from the growth chamber to the STM chamber. After annealing at 773 K to remove the Se adlayer, STM images show that WSe2 layers nucleate at both step edges and terraces of the HOPG. Exposure to air for 1 week and 9 weeks caused air-induced adsorbates to be deposited on the WSe2 surface; however, the band gap of the terraces remained unaffected and nearly identical to those on decapped WSe2. The air-induced adsorbates can be removed by annealing at 523 K. In contrast to WSe2 terraces, air exposure caused the edges of the WSe2 to oxidize and form protrusions, resulting in a larger band gap in the scanning tunneling spectra compared to the terraces of air-exposed WSe2 monolayers. The preferential oxidation at the WSe2 edges compared to the terraces is likely the result of dangling edge bonds. In the absence of air exposure, the dangling edge bonds had a smaller band gap compared to the terraces and a shift of about 0.73 eV in the Fermi level toward the valence band. However, after air exposure, the band gap of the oxidized WSe2 edges became about 1.08 eV larger than that of the WSe2 terraces, resulting in the electronic passivation of the WSe2.

Phase evolution in mixture of cobalt and fullerene deposited from vapor

Recently we reported the evidence of solubility of Co in solid C60 found from magnetization of the CoxC60 mixture films (Phys. D: Appl. Phys. 48, 2015, 335002). In the present study we identified the Co solubility limit (xc = 2) and specified phase evolution in the CoxC60 mixtures in a wide interval of the Co concentrations (0 < x < 50) that was carried out through systematic characterization of the film surface morphology, chemical and phase composition. The effect of air exposure allowed us to recognize three intervals of x where phase evolution is controlled by rather different mechanisms. In the first interval (0 < x < 2, dilute mixtures) the phase evolution yields two separated phases, namely fcc-C60 and Co2C60. The dilute films do not include Co clusters and almost insensitive to the air exposure. Within the second and third intervals (supersaturated mixtures) designated as xc < x < xm and xm < x, respectively (xm = 10÷15), the formation of the Co clusters dominates in the phase evolution, which are found to be sensitive to the air exposure. The Co clustering in the mixtures from the second interval is completed by formation of critical nuclei. Within the third interval of x the phase evolution is controlled by growth of the Co clusters due to coalescence process.

Combining air recharging and membrane superhydrophobicity for fouling prevention in membrane distillation

In previous studies of the desalination technology membrane distillation (MD), superhydrophobicity of the membrane has been shown to dramatically decrease fouling in adverse conditions, but the mechanism for this is not well understood. Additionally, air layers present on submerged solid superhydrophobic surfaces have been shown to dramatically reduce biofouling, and air-bubbling has been used to reducing fouling and increase flux and efficiency in MD. The present work studies the effect of maintaining air layers on the membrane surface and superhydrophobicity as a new method for preventing fouling of MD membranes by salts, particulates, and organic particles. Superhydrophobic MD membranes were prepared using initiated chemical vapor deposition (iCVD) of perfluorodecyl acrylate (PFDA) on poly(vinyldene fluoride) PVDF membranes and used to study the effects of surface energy on fouling. A static MD setup with evaporation through an MD membrane but no condensing of permeate was used to examine the effect of air exposure on fouling, by measuring the increase in weight of the membrane caused by scale deposition. Theory was derived for the reduction of fouling on superhydrophobic surfaces, and a review of related theory was included. Air layers may displace fouling gels, reduce the area of feed in contact with the membrane, reduce foulant adhesion, and enhance superhydrophobicity in a Cassie–Baxter state. The study shows that the presence of air on the membrane surface significantly reduces biological fouling, but in some cases had mildly exacerbating effects by increasing crystal formation of salts, especially when the air was not saturated with water vapor. Air recharging combined with superhydrophobicity reduced fouling in several cases where hydrophobic membranes alone did little.

Experimental Investigation on Contact Angle of Sintered Copper Powder Wick

Heat pipes are widely used in electronic cooling and other applications that require efficient transport or spreading of heat from local sources of high heat flux. One factor that most affect the performance of this device is the wetting properties of the wick material, whereby a hydrophilic wick material is required to transport the liquid from the evaporator to the condenser. The performance of heat pipe will decrease when the wick surface becomes hydrophobic as indicated by changes in its contact angle (CA). This study aims to determine the effect of ambient air exposure on the wettability of wick material. Wettability for a surface by a certain liquid can be shown by measuring the contact angle of liquid droplets on the surface. In this experiment, the contact angle was captured using a high speed video camera followed by image processing and then measured using Image J software. The surface of the sample/wick is a sintered copper powder which in this study through a process of forming or compaction by various parameters such as powder particle size, compacting pressure and sintering temperature. From the results of this study was found that the longer wicks were exposed in the ambient air, the contact angle of the liquid on the wick surface will be getting increased. After 7 days were contaminated on the ambient air, then all samples have been turned into hydrophobic, CA&gt;90°.

Hydrogenation Properties of TiFe Doped with Zirconium

The goal of this study was to optimize the activation behaviour of hydrogen storage alloy TiFe. We found that the addition of a small amount of Zr in TiFe alloy greatly reduces the hydrogenation activation time. Two different procedural synthesis methods were applied: co-melt, where the TiFe was melted and afterward re-melted with the addition of Zr, and single-melt, where Ti, Fe and Zr were melted together in one single operation. The co-melted sample absorbed hydrogen at its maximum capacity in less than three hours without any pre-treatment. The single-melted alloy absorbed its maximum capacity in less than seven hours, also without pre-treatment. The reason for discrepancies between co-melt and single-melt alloys was found to be the different microstructure. The effect of air exposure was also investigated. We found that the air-exposed samples had the same maximum capacity as the argon protected samples but with a slightly longer incubation time, which is probably due to the presence of a dense surface oxide layer. Scanning electron microscopy revealed the presence of a rich Zr intergranular phase in the TiFe matrix, which is responsible for the enhanced hydrogenation properties of these Zr-doped TiFe alloys.