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Reducing the cost of hydrogen transport is an important priority for the proliferation of clean hydrogen to decarbonize the economy. It is possible to alleviate the hydrogen transportation costs by delivering them via existing natural gas pipeline infrastructure. This strategy, however, necessitates the dilution of hydrogen by blending it with natural gas as hydrogen embrittlement pipeline materials. In this work, we deploy high-temperature polymer electrolyte membrane electrochemical hydrogen pumps (HT-PEM EHPs) to purify hydrogen from dilute hydrogen–natural gas mixtures (5 to 20 vol % hydrogen). Interestingly, we observe that activation overpotentials govern HT-PEM EHP polarization when feeding dilute hydrogen mixtures. Pressurizing the anode to 1.76 barabs enables us to ameliorate interfacial mass transfer resistance and achieve an EHP limiting current density of 1.4 A cm–2 with a 10 vol % of hydrogen in a natural gas feed. The HT-PEM EHP showed a small degradation rate, 44 μV h–1, during a 100 h durability test.
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Carbon doping switching on the hydrogen adsorption activity of NiO for hydrogen evolution reaction
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null (Ed.)For over eighty years, scientists have been trying to produce lab-made metallic hydrogen, the holy grail of alternative fuels. In that process, diamond anvils must withstand pressures greater than those at the center of the earth—no mean feat. Recent research may have finally achieved hydrogen’s metallic state. All that remains is for another lab to reproduce the results.more » « less
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As the exigency for decarbonizing sectors such as utilities, heavy-duty transportation, and manufacturing has risen, interest in hydrogen technologies has intensified accordingly. Among the safety issues being addressed for hydrogen technologies is the potential for hydrogen embrittlement of steels, which are commonly specified for pressure boundaries in containment components. From an engineering perspective, hydrogen embrittlement of steels can be managed through conventional design and fitness-for-service (FFS) practices provided the mechanical property inputs are measured appropriately, i.e., testing of steels is performed in the hydrogen environment. Given the increasing need for managing hydrogen embrittlement to safely operate high-pressure containment components, the purpose of this review is to comprehensively survey and critically assess the literature on the following mechanical properties of steels in gaseous hydrogen that serve as inputs to design and FFS analyses: threshold stress-intensity factor or threshold J-integral for subcritical, time-dependent cracking, fatigue crack growth rate, and total fatigue life. The review focuses on such mechanical properties in gaseous hydrogen for carbon-manganese (C-Mn) steels, low-alloy steels, austenitic stainless steels, duplex stainless steels, as well as the ferritic and martensitic stainless steels, since these are most pertinent to containment components in hydrogen technology. Three high-level conclusions from the review are the following: 1) mechanical property data for C-Mn and low-alloy steels in hydrogen gas are sufficiently mature so that conservative limits can be specified for design and FFS analyses, 2) mechanical property data for austenitic stainless steels must be supplemented with additional measurements, particularly from specimens tested in high-pressure hydrogen gas, before conservative limits can be defined for design and FFS analyses, and 3) mechanical property data for ferritic, martensitic, and duplex stainless steels in hydrogen gas are so scarce that design and FFS analyses covering wide ranges of steel grades and component service conditions are currently not feasible.more » « less
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We used the method of electron spin resonance (ESR) to investigate the temperature-dependent recombination rate of H atoms in solid molecular hydrogen deuteride (HD). A 1.5 휇m thick solid molecular HD film was deposited at a rate of 2 monolayer/s, onto a gold surface maintained at T=1.5 K. H and D atoms were accumulated in the film by maintaining radio-frequency electric discharge above the film for 19 days. After further storage of the sample for 48 h, at T < 1 K, the D atom signal vanished. The concentration of H atoms was monitored as the sample was warmed stepwise from 1.1 K to 2.8 K. The recombination rate of H atoms in solid HD was found to be proportional to temperature in this range.more » « less
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1038/s41467-020-14462-2
