Synergistic Effect Of Hydrogen Research Articles

Efficient hydrogenolysis of woody plant lignin into phenolic compounds over a CuO/CeO2 catalyst

Hydrogenolysis of lignocellulose into renewable phenolic monomers through the reductive catalytic degradation (RCD) strategy is limited by cost and applicability, and there is a need to develop effective catalysts with controlled cost and greater applicability. Herein, we report the fabrication of CuO/CeO2 catalyst toward RCD of lignocellulose for the production of monomeric phenols with different side chains. The catalyst can be adapted to softwoods (Larch and Pinus) and hardwoods (Eucalyptus and Poplar) with yields ranging from 8.8 % to 31.4 %, which afford certain monomer yields while controlling costs. Experimental results demonstrate that the acidic and basic sites of the CuO/CeO2 catalyst assist the metal sites in the depolymerization of lignin. Notably, the mechanistic investigation reveal that the methoxylation process occurs on the aliphatic hydroxyl group. Moreover, the synergistic effects of hydrogen and catalyst exhibit high hydrogenolysis activity, which contributes to the efficient C − O bond scission, thus generating the target monomer products.

Effect of hydrogen on the pitting corrosion behavior of Incoloy 825

PurposeIn this paper, the authors aim to study the effect of hydrogen on the pitting corrosion behavior of Incoloy 825, a commonly used material for heat exchanger tubes in hydrogenated heat exchangers.Design/methodology/approachThe pitting initiation and propagation behaviors were investigated by electrochemical and chemical immersion experiments and observed and analyzed by scanning electron microscope and energy dispersive spectrometer methods.FindingsThe results show that hydrogen significantly affects the electrochemical behavior of Incoloy 825; the self-corrosion potential decreased from −197 mV before hydrogen charging to −263 mV, −270 mV and −657 mV after hydrogen charging, and the corrosion current density increased from 0.049 µA/cm2 before hydrogen charging to 2.490 µA/cm2, 2.560 µA/cm2 and 2.780 µA/cm2 after hydrogen charging. The pitting susceptibility of the material increases.Originality/valueHydrogen is enriched on the precipitate, and the pitting corrosion also initiates at that location. The synergistic effect of hydrogen and precipitate destroys the passive film on the metal surface and promotes pitting initiation.

水素助長粒界破壊を伴う純ニッケルの延性低下における水素と硫黄の相乗的役割

Synergistic effect of hydrogen and sulfur on intergranular (IG) fracture and resultant ductility loss in pure nickel was quantitatively evaluated by means of Auger electron spectroscopy, thermal desorption analysis and slow strain rate tensile test. Both hydrogen and sulfur enhanced IG fracture, leading to the degradation of ductility. Increased sulfur concentration at grain boundaries (GBs) resulted in an appearance of second peak around 400°C in TDA profiles, indicating that the segregated GB sulfur trapped hydrogen. However, its trapped hydrogen hardly enhanced the hydrogen-induced ductility loss. Instead, hydrogen directly trapped at GBs was responsible for IG fracture and degradation of ductility. These results indicate hydrogen and sulfur independently induced the IG fracture and resultant ductility loss and therefore, the synergistic effect is negligible.

Effect of hydrogen on pitting corrosion of 2205 duplex stainless steel under alternating dry/wet marine environment

Stainless steels play an extremely vital role in the field of marine engineering equipment. However, stainless steel products in service are still subject to corrosion from severe environments such as alternating dry/wet condition and damage caused by hydrogen introduced during heat treatment or cathodic protection. Under alternating dry/wet marine environment, the synergistic effect of hydrogen and corrosion can influence the corrosion resistance of stainless steels dramatically. In this work, the corrosion behavior and mechanism of 2205 duplex stainless steel under alternating dry/wet marine environment are investigated before and after hydrogen charging using electrochemical testing, component characterization and morphological observation. The results show that the open circuit potential, film resistance and breakdown potential all reduce and the passive current density increases after 12 h hydrogen charging. The ratio of Fe3+ and O2−/OH− decreases. The components of the hydrogen charged passive film alter and the performance deteriorates. The number of surface pits increases after 12 h hydrogen charging and additional 10 d alternating dry/wet corrosion. The pitting potential drops much lower. Consequently, The synergistic effect of high concentrations of Cl− in the thin liquid film and hydrogen accelerates the destruction of the passive film, further reducing the corrosion resistance of stainless steels.

Synergistic effect of hydrogen and waste lubricating oil on the performance and emissions of a compression ignition engine

The demand for energy is increasing every year. For a long time, fossil fuels have been used to satiate this energy demand. However, using hydrocarbon-based fossil fuels has led to an enormous rise of carbon dioxide levels in the atmosphere resulting in global warming. It is therefore necessary to look for alternatives to fossil fuels. The research carried out till date have shown biomass and waste-derived fuels as plausible alternatives to fossil fuels. The biomass feedstock includes jatropha oil, Karanja oil, cottonseed oil, and hemp oil among others and wastes include used cooking oil, used engine oil, used tire and used plastics etc. In this study, the authors aim to explore waste lubrication oil as a fuel for the diesel engine. The used lubrication oil was pyrolyzed and diesel-like fuel with 80% conversion efficiency was obtained. A blend of the fuel and diesel in the ratio of 80:20 on volume basis was prepared. Engine experiments at various load conditions was carried out with the blend. As compared to diesel, a 2% increase in thermal efficiency, 6.3%, 16.1% and 13.6% decrease in smoke, CO and HC emissions & 3.2% and 1.8% increase in NOx and CO2 emission were observed at full load with the blend. With an aim to further improve the engine performance and reduce the overall emissions from the engine exhaust, a zero-carbon fuel namely gaseous hydrogen was inducted in the intake manifold. The flow rate of hydrogen was varied from 3 to 12 Litres per minute (LPM). As compared to diesel, at maximum hydrogen flow rate the thermal efficiency increased by 12.2%. HC, CO and smoke emissions decreased by 42.4%, 51.6% and 16.8%, whereas NOx emissions increased by 22%. The study shows that the combination of pyrolyzed waste lubricant and hydrogen were found to be suitable as a fuel for an unmodified diesel engine. Such fuel combination can be used for stationary applications such as power backups.

Strong and tough collagen/cellulose nanofibril composite films via the synergistic effect of hydrogen and metal–ligand bonds

In this paper, the collagen (COL)/cellulose nanofibril (CNF) composite films were fabricated via solution casting-solvent evaporation induced COL molecule self-assembly in CNF supramolecular network to form a high-density physically crosslinked supramolecular double network and then moved to inorganic saline solutions to induce the structure rearrangement and crosslinking of the composite films on the nanoscale through soaking. The supramolecular double network structure and synergistic effect of hydrogen and metal–ligand bonds on the mechanical properties of the COL/CNF composite films were also investigated through various characterization techniques to thoroughly comprehend the reinforcement mechanism. COL/CNF composite films with ferric ion exhibited excellent thermal stability, outstanding dry and wet mechanical performances (112.7 MPa and 55.5 MPa). Additionally, the composite films displayed super bioactivity and antimicrobial activity even in the presence of metal ions, making them promising materials for tissue engineering and regenerative medicine.

Synergistic effect of hydrogen and nanoscale zero-valent iron on ex-situ biogas upgrading and acetate recovery

Hydrogen (H2) assisted ex-situ biogas upgrading and liquid chemicals production can augment the fossil fuel-dominated energy market, and alleviate CO2-induced global warming. Recent investigations confirmed that nanoscale zero-valent iron (nZVI) enabled the enhancement of anaerobic digestion for biogas production. However, little is known about the effect of nZVI on the downstream ex-situ biogas upgrading. Herein, different levels (0 mg L−1, 100 mg L−1, 200 mg L−1, 500 mg L−1, 1000 mg L−1, 2000 mg L−1) of nZVI were added for H2-assisted ex-situ biogas upgrading, to study whether nZVI could impact the biomethane purity and acetate yield for the first time. Results showed that all tested nZVI levels were favorable for biogas upgrading in the presence of H2, the highest biomethane content (94.1 %, v/v), the CO2 utilization ratio (95.9 %), and acetate yield (19.4 mmol L−1) were achieved at 500 mg L−1 nZVI, respectively. Further analysis indicated that increased biogas upgrading efficiency was related to an increase in extracellular polymeric substances, which ensures the microbial activity and stability of the ex-situ biogas upgrading. Microbial community characterization showed that the Petrimonas, Romboutsia, Acidaminococcus, and Clostridium predominated the microbiome during biogas upgrading at 500 mg L−1 nZVI with H2 supply. These results suggested that nZVI and H2 contributed jointly to promoting the bioconversion of CO2 in biogas to acetate. The findings could be helpful for paving a new way for efficient simultaneous ex-situ biogas upgrading and liquid chemicals recovery.

Synergistic Effect of Hydrogen and 5-Aza on Myogenic Differentiation through the p38 MAPK Signaling Pathway in Adipose-Derived Mesenchymal Stem Cells.

This study aims to clarify the systems underlying regulation and regulatory roles of hydrogen combined with 5-Aza in the myogenic differentiation of adipose mesenchymal stem cells (ADSCs). In this study, ADSCs acted as an in vitro myogenic differentiating mode. First, the Alamar blue Staining and mitochondrial tracer technique were used to verify whether hydrogen combined with 5-Aza could promote cell proliferation. In addition, this study assessed myogenic differentiating markers (e.g., Myogenin, Mhc and Myod protein expressions) based on the Western blotting assay, analysis on cellular morphological characteristics (e.g., Myotube number, length, diameter and maturation index), RT-PCR (Myod, Myogenin and Mhc mRNA expression) and Immunofluorescence analysis (Desmin, Myosin and β-actin protein expression). Finally, to verify the mechanism of myogenic differentiation of hydrogen-bound 5-Aza, we performed bioinformatics analysis and Western blot to detect the expression of p-P38 protein. Hydrogen combined with 5-Aza significantly enhanced the proliferation and myogenic differentiation of ADSCs in vitro by increasing the number of single-cell mitochondria and upregulating the expression of myogenic biomarkers such as Myod, Mhc and myotube formation. The expressions of p-P38 was up-regulated by hydrogen combined with 5-Aza. The differentiating ability was suppressed when the cells were cultivated in combination with SB203580 (p38 MAPK signal pathway inhibitor). Hydrogen alleviates the cytotoxicity of 5-Aza and synergistically promotes the myogenic differentiation capacity of adipose stem cells via the p38 MAPK pathway. Thus, the mentioned results present insights into myogenic differentiation and are likely to generate one potential alternative strategy for skeletal muscle related diseases.

Synergistic effects of hydrogen and deformation temperature on mechanical properties of TRIP-aided bainitic ferrite steel

Mechanical properties of TRIP-aided steel with bainitic ferrite matrix in the presence of hydrogen were investigated at the deformation temperature range of −100 to 100 °C. In hydrogen-uncharged condition, the yield strength (YS) first increased and then remained almost unchanged, while the highest uniform elongation (UEl) was observed at a deformation temperature of 21 °C. Hydrogen charging slightly increased the YS and deteriorated the UEl at all the temperature ranges. In the hydrogen-uncharged and hydrogen-charged specimens, the transformation ratio of retained austenite increased with a decrease in the deformation temperature; however, the hydrogen charging decreased the transformation ratio. The fracture behavior drastically changed when hydrogen was introduced, owing to which deformation-induced martensitic transformation occurred and hydrogen played dual roles in accelerating brittle-like cracking.

In-situ TEM investigation of dislocation loop reaction and irradiation hardening in H2+-He+ dual-beam irradiated Mo

• Irradiation can directly cause the formation of 1/2<111> loops and <100> loops. • Irradiation can directly induce 1/2<111>loop to transform into <100> loop. • Two 1/2<111> loops react to form <100> loop without strict size similarity condition. • Yield strength increment caused by irradiation-induced loops is analyzed. • Loop evolution and its relationship with irradiation dose are established. Through in-situ TEM observation during 30 keV H 2 + -He + dual-beam irradiation at 723 K, the reaction and transformation of dislocation loops in pure Mo were investigated, especially for <100> loops. Irradiation could directly cause the formation of 1/2<111> loops and <100> loops, but 1/2<111> loops were dominant. In-situ observation confirmed the formation mechanism of <100> loops, including direct irradiation induced mechanism, 1/2<111> loop direct conversion mechanism, and reaction mechanism of two 1/2<111> loops. Meanwhile, the reaction of two 1/2<111> loops to produce <100> loop should not require the strict size similarity condition. The reaction between 1/2<111> loops could also produce 1/2<111> loop, which was essentially a process in which one loop absorbed another one. The yield strength increment caused by irradiation-induced loops was analyzed, and its saturation value reached 0.48 GPa at 0.06 dpa. Compared with single He + irradiation, the number density and average diameter of loops increased significantly and more serious damage was caused under the synergistic effect of hydrogen and helium. The mechanism based on in-situ experimental observation was discussed in depth. Graphical Abstract .

Repairing irreversible hydrogen–induced damages using electric current pulse

The synergistic effect of hydrogen and stress will cause various damages to metallic materials, such as hydrogen–induced cracks, blisters, voids, which would cause unpredictable failure of the metallic materials. In this study, the mechanical properties of high–strength steel with hydrogen damages were effectively restored after electropulsing treatment. The reasons are that the hydrogen content was reduced to a lower concentration on the one hand, and the hydrogen damages (microcracks and voids) were partially repaired on the other hand. Essentially, the introduction of an applied electric field increases the free energy of the system and reduces the energy barrier for diffusion of hydrogen, resulting in faster diffusion of hydrogen and lower hydrogen content. Simultaneously, the temperature rises and compressive stress induced by electropulsing are accountable for the healing of hydrogen damages.

Research progress of hydrogen/helium effects in metal materials by positron annihilation spectroscopy

An important feature of the irradiation process in nuclear system is the formation of large displacement cascades, in which primary knock-on atoms and secondary particles formed by nuclear reactions generate a considerable number of defects such as dislocations, vacancies and transmutation gases. Predicting and mitigating the adverse effects of damage defect and transmutation hydrogen/helium produced by high-dose neutron irradiation on the mechanical properties of structural materials is the most significant challenge facing the current development of nuclear energy. To solve this problem, understanding the interaction mechanism between hydrogen/helium atoms and micro-defects is a very important breakthrough. Precursors of helium/ hydrogen bubble, small helium/hydrogen-filled vacancy complexes, may play an important role in realizing bubble nucleation, and the formation of these complexes is affected by many factors. However, only a little information about helium/hydrogen-vacancy clusters’ behavior has been obtained in metal/alloy materials. This is mainly limited by the characterization methods, such as the limited resolution of transmission electron microscope (TEM). Helium/hydrogen-vacancy clusters cannot be observed by TEM before the formation of helium bubbles. Applications of positron annihilation to the study of crystal lattice defects started around 1970s, when it was realized that positron annihilation is particularly sensitive to vacancy-type defects and that annihilation properties manifest the nature of each specific type of defect. In recent years, with the continuous development of slow positron beam and the improvement of various experimental testing methods based on slow positron beam, the application of positron annihilation technology has been extended to the research field of hydrogen/helium behavior in metal materials, which plays an important role in studying the hydrogen/helium radiation damage to metal materials. In this review, the basic principles of positron annihilation spectroscopy are briefly discussed and the three most important measurement methods used for hydrogen/helium effect studies are described (i.e. positron annihilation lifetime spectroscopy (PALS), Doppler broadening spectroscopy (DBS), coincidence Doppler broadening spectroscopy (CDBS)). In this paper, the application of positron annihilation spectroscopy to the study of hydrogen/helium behavior in metal materials is reviewed in combination with the reported relevant developments (including our research group’s achieve-ments). The advantages of three commonly used measurement methods in the following specific studies are highlighted: 1) The estimation of bubble size and concentration; 2) irradiation damage induced by hydrogen/helium; 3) the evolution behavior of irradiation-induced defects in the heat treatment process; 4) sy-nergistic effect of hydrogen and helium.

The synergistic effect of hydrogen and helium implantations in forming H2 molecules in a Fe-12 wt.%Cr-ODS steel characterized by Raman spectroscopy and SIMS

Oxide-dispersion strengthened ferritic steels (ODS) are candidates for a use as first-wall materials in future fusion reactors. This application will lead to neutron bombardment and associated helium and hydrogen production by transmutation. The synergistic effects of irradiation damage, helium and hydrogen in a Fe-12 wt.%Cr-0.4 wt.%Y2O3 steel are studied via ion irradiations of this material by 24 MeV Fe8+/600 keV H+ and 1.0 MeV He+/600 keV H+ dual beams, H+ single beam and Fe8+/He+/H+ triple beam. Subsequent analyses of hydrogen in the irradiated ODS by secondary-ion mass spectrometry (SIMS) and Raman spectroscopy were carried out to profile hydrogen and to characterize the formation of the di-hydrogen molecule (H2).The results show that irradiation damage and helium play a role in the retention of hydrogen in the specimen. The formation of the H2 molecule is observed only when the ODS steel is co-irradiated with H and He beams in dual or triple modes.

Achieving a Superlong Lifetime in the Zeolite-Catalyzed MTO Reaction under High Pressure: Synergistic Effect of Hydrogen and Water

Zeolites are usually considered to be acid catalysts, which are prone to deactivation due to the coke deposition in the hydrocarbon conversions such as methanol-to-olefins (MTO) reaction. Herein, a high-pressure MTO process with cofeeding H2 and H2O is reported, which can effectively prolong the catalytic lifetime of SAPO-34. The corresponding methanol handling capacity is about 200 times larger than that under the normal-pressure condition. Investigation reveals that the ultralong lifetime originates from the hydrogenation ability of the acid sites on SAPO-34 for aromatic species, which can hydrogenate the heavy aromatic deposits (especially the phenanthrene composed of three benene rings) to active aromatic intermediates (methylbenzenes and methylnaphthalenes) and thus slow down the evolution of coke species. A positive synergistic effect between H2 and H2O on prolonging the catalyst lifetime is observed at higher H2O partial pressure, likely resulting from the reduced barriers of hydrogenation reaction...

Study on synergistic effects of H and He in α-Fe

The synergistic effect of hydrogen and helium in α-Fe has been investigated using density functional theory calculation method. In perfect crystal of Fe, the presence of helium atom would decrease the dissolution energy of hydrogen atom near helium atom. This implies the existence of an attractive interaction between hydrogen and helium atoms. It is also revealed that the most stable places for both hydrogen and helium atoms are two tetrahedral sites (T-site) with a distance of 2.16 Å. Furthermore, a vacancy-helium complex (Va–He) would be an effective trapping site for hydrogen atom compared with mono-vacancy, a Va–He would be able to trap 8 hydrogen atoms.

Fabrication of strong nanocomposite films with renewable forestry waste/montmorillonite/reduction of graphene oxide for fire retardant

It is desirable to develop products comprised of biodegradable components from green resources or renewable waste due to a shortage of fossil fuel. Wood auto-hydrolysates (WH) are generated in the hydrothermal treatment of the pulping process, which contains large amounts of hemicelluloses and some lignin. In this work, a green and facile route similar to paper making is proposed to convert WH to value-added nanocomposite films. WH was combined with montmorillonite (MMT) as the basic components together with a small quantity of graphene oxide (GO) to produce a ternary, bioinspired nanocomposite film with high strength and fire resistance properties. GO was initially introduced to fabricate the WH-MMT-GO nanocomposites, the interfacial interaction between WH, MMT, and GO was enhanced by the synergistic effect of hydrogen and covalent bonds. The nanocomposite film WH-MMT-rGO (F0.8%rGO) with only 0.8 wt% rGO exhibited promising features, such as a good thermal stability, and a high strength of 124 MPa, which was better than other hemicellulose-based films or wood auto-hydrolysate based films. The combustion behavior of WH-MMT-GO films was determined by microscale combustion calorimeter (MCC), and the results suggested the films had excellent fire resistance, where the peak heat release rate (PHRR) of the films was reduced by more than 90% compared to the neat WH. Furthermore, the hemicellulose-based films are reported to be hydrophilic, while the WH-MMT-rGO films proved to be hydrophobic due to the introducing of rGO. The proposed synthetic strategy could make the wood auto-hydrolysate useful for fabrication of fire-protective films, coatings, packaging, etc.

Synergistic effects of hydrogen and halogen bonding in co-crystals of dipyridylureas and diiodotetrafluorobenzenes

Herein, we investigate co-crystallization of three linear co-formers that contain urea and pyridyl groups with three regioisomers of diiodotetrafluorobenzene (DITFB) to afford eleven co-crystals. The linear o-, m-, and p- dipyridylureas vary distance and geometry between the urea carbonyl oxygen and two pyridyl nitrogen acceptors, while the donors consist of urea NH groups and the activated halides in DITFB. Electrostatic potential calculations suggest that the o-dipyridylurea co-former presents two significantly different acceptors. In comparison, the acceptors in the m- and p-dipyridylurea co-formers display electrostatic potentials within 5–6 kJ/mol and should be competitive, potentially leading to altered assembly motifs. Overall, ten of the co-crystals consistently display the urea assembly motif as the best acceptor/donor pair. Seven structures were obtained as the predicted 1:1 ratio with halogen bonding interactions linking ditopic halogen bond donors and the pyridyl units through N···I interactions ranging from 78.4 to 83.1% of the van der Waals radii. Modified structures were more likely when there was a structural mismatch with the geometrically challenging o-DITFB donor and m- or p-dipyridylurea co-former. The majority of the co-crystal structures (10/11) demonstrated fully satisfied hydrogen and halogen bonding interactions suggesting that these synthons can be used synergistically to generate complex solid-state structures.

Novel hydrogen- and halogen-bonding anion receptors based on 3-iodopyridinium units

Iodopyridinium-based tripodal receptors strongly bind anionic species in their bowl-shaped cavity through the synergistic effect of hydrogen- and halogen-bonding interactions.

Synergistic Effects of Hydrogen and Stress on Corrosion of X100 Pipeline Steel in a Near-Neutral pH Solution

In this work, scanning vibrating electrode technique and local electrochemical impedance spectroscopy measurements were used to investigate the effects of stress and hydrogen on electrochemical corrosion behavior of a X100 pipeline steel in a near-neutral pH solution. The stress distribution on the test specimen was calculated using the finite element method. Results demonstrated that the hydrogen-charging enhances the local anodic dissolution of the steel, contributing to the formation of a layer of corrosion product. However, there is little difference of the charge-transfer resistance between the regions with and without hydrogen-charging due to rapid diffusion of hydrogen atoms throughout the specimen with time. When the local stress concentration is not significant enough to approach the yielding strength of the steel, the steel is still in a relatively stable state, and there is a uniform distribution of dissolution rate over the whole surface of the steel specimen. Although the stress-enhanced activation is not sufficient to result in an apparent difference of current density of the steel, the activation of the steel would activate dislocations, which serve as effective traps to the charged hydrogen atoms. With the increase of hydrogen concentration, the hydrogen-enhanced anodic dissolution becomes dominant.

Effect of hydrogen on stress corrosion cracking of copper

The effects of hydrogen on electrochemical behavior and susceptibility of stress corrosion cracking (SCC) of pure copper were studied. SCC susceptibility of pure copper in a 1 M NaNO2 solution was increased by pre-charged hydrogen. The effect of hydrogen on the susceptibility is more obvious in the low stress region due to the longer fracture time, which resulted in a longer time for more hydrogen to diffuse toward the crack tip. Synergistic effects of hydrogen and stress on corrosion and SCC processes were discussed. The results showed that an interaction between stress and hydrogen at the crack tip could increase the anodic dissolution rate remarkably.