Evidence of molecular hydrogen trapped in two-dimensional layered titanium carbide-based MXene

Journal Article · 16 July 2017 · Physical Review Materials

DOI: https://doi.org/10.1103/PhysRevMaterials.1.024004 · OSTI ID:1376464

Osti, Naresh C. ^[1]; Naguib, Michael ^[1]; Tyagi, Madhusudan ^[2]; Gogotsi, Yury ^[3]; Kolesnikov, Alexander I. ^[1]; Mamontov, Eugene ^[1]

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1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
2. National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States); Univ. of Maryland, College Park, MD (United States)
3. Drexel Univ., Philadelphia, PA (United States)

Two-dimensional transition metal carbides and nitrides (MXenes) are one of the largest and fastest growing families of materials. The presence of molecular hydrogen at ambient conditions in a MXene (Ti₃C₂T_x, where T_x represents a surface terminating species, including O, OH, and F) material is revealed here by inelastic and elastic neutron scatterings. The inelastic neutron-scattering spectrum measured at 5 K shows a peak at 14.6 meV, presenting a clear indication of the presence of parahydrogen in the MXene synthesized using 48% hydrofluoric acid and annealed at 110°C in vacuum prior to the measurement. An increase in the measurement temperature gradually reduces the peak intensity and increases the peak width due to the mobility of the molecular hydrogen in confinement. The presence of molecular hydrogen is confirmed further from the observed elastic intensity drop in a fixed energy-window scan of elastic intensity measurements in the temperature range of 10–35 K. Using milder etching conditions, ion intercalation, or an increase in the annealing temperature all result in the absence of the trapped hydrogen molecules in MXene. Here, the results of this paper can guide the development of MXene materials with desired properties and improve our understanding of the behavior of MXenes in applications ranging from supercapacitors to hydrogen evolution reaction catalysis and hydrogen storage.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Energy Frontier Research Centers (EFRC) (United States). Fluid Interface Reactions, Structures and Transport Center (FIRST)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 1376464
• Alternate ID(s): OSTI ID: 1371611
• Journal Information: Physical Review Materials, Journal Name: Physical Review Materials Journal Issue: 2 Vol. 1; ISSN PRMHAR; ISSN 2475-9953
• Publisher: American Physical Society (APS)Copyright Statement
• Country of Publication: United States
• Language: English