Methane hydrate formation in confined nanospace can surpass nature

Natural methane hydrates are believed to be the largest source of hydrocarbons on Earth. These structures are formed in specific locations such as deep-sea sediments and the permafrost based on demanding conditions of high pressure and low temperature. Here we report that, by taking advantage of the confinement effects on nanopore space, synthetic methane hydrates grow under mild conditions (3.5 MPa and 2 degrees C), with faster kinetics (within minutes) than nature, fully reversibly and with a nominal stoichiometry that mimics nature. The formation of the hydrate structures in nanospace and their similarity to natural hydrates is confirmed using inelastic neutron scattering experiments and synchrotron X-ray powder diffraction. These findings may be a step towards the application of a smart synthesis of methane hydrates in energy-demanding applications (for example, transportation).We acknowledge UK Science and Technlology Facilities Council for the provision of beam time on the TOSCA spectrometer (Projects RB1410624 and RB122099) and financial support from the European Commission under the 7th Framework Programme through the 'Research Infrastructures' action of the 'Capacities' Programme (NMI3-II Grant number 283883). J.S.-A. and F.R. acknowledges the financial support from MINECO: Strategic Japanese-Spanish Cooperation Program (PLE2009-0052), Concert Project-NASEMS (PCIN-2013-057) and Generalitat Valenciana (PROMETEO/2009/002). F.R. and J.L.J. thank the financial support from MINECO (MAT2012-38567-C02-01, Consolider Ingenio 2010-Multicat CSD-2009-00050 and SEV-2012-0267). K.K. thanks Grant-in-Aid for Scientific Research (A) (2424-1038), Japan. A.B. and A.U. thank the financial support from MINECO (SEV-2013-0319). J.L.J. and I.P. thank synchrotron ALBA for beamtime availability.Casco, M.; Silvestre Albero, J.; Ramirez-Cuesta, A.; Rey Garcia, F.; Jorda Moret, JL.; Bansode, A.; Urakawa, A.... (2015). Methane hydrate formation in confined nanospace can surpass nature. Nature Communications. 6(6432):1-8. https://doi.org/10.1038/ncomms7432S1866432Sloan, E. D. Jr., & Koh, C. A. Clathrate Hydrates of Natural Gases 3rd edn CRC Press (2007).Gutt, C. et al. The structure of deuterated methane-hydrate. J. Chem. Phys. 113, 4713–4721 (2000).Holbrook, W. S., Hoskins, H., Wood, W. T., Stephen, R. A. & Lizarralde, D. Methane hydrate and free gas on the Blake Ridge from vertical seismic profiling. Science 273, 1840–1843 (1996).Sloan, E. D. Jr., Fundamental principles and applications of natural gas hydrates. Nature 426, 353–363 (2003).Rodríguez-Reinoso, F., Almansa, C. & Molina-Sabio, M. Contribution to the evaluation of density of methane adsorbed on activated carbon. J. Phys. Chem. B 109, 20227–20231 (2005).Kockrick, E. et al. Ordered mesoporous carbide derived carbons for high pressure gas storage. Carbon 48, 1707–1717 (2010).Klein, N. et al. A mesoporous metal-organic framework. Angew. Chem. Int. Ed. 48, 9954–9957 (2009).Makal, T. A., Li, J.-R., Lu, W. & Zhou, H.-C. Methane storage in advanced porous materials. Chem. Soc. Rev. 41, 7761–7779 (2012).Peng, Y. et al. Methane storage in metal-organic frameworks: Current records, surprise findings, and challenges. J. Am.Chem. Soc. 135, 11887–11894 (2013).Casco, M. E. et al. High-pressure methane storage in porous materials: are carbon materials in the pole position? Chem. Mater 27, 959–964 (2015).Ramos-Fernández, J. M., Martínez-Escandell, M. & Rodríguez-Reinoso, F. Production of binderless activated carbon monoliths by KOH activation of carbon mesophase materials. Carbon 46, 384–386 (2008).Marsh, H. & Rodríguez-Reinoso, F. Activated Carbon Elsevier (2006).Kubo, T. et al. Diffusion-barrier-free porous carbon monoliths as a new form of activated carbon. ChemSusChem 5, 2271–2277 (2012).Kaneko, K., Itoh, T. & Fujimori, T. Collective interactions of molecules with an interfacial solid. Chem. Lett. 41, 466–475 (2012).Nakamura, M., Ohba, T., Branton, P., Kanoh, H. & Kaneko, K. Equilibrium-time and pore-width dependent hysteresis of water adsorption isotherm on hydrophobic microporous carbons. Carbon 48, 305–308 (2010).Vysniauskas, A. & Bishnoi, P. R. A kinetic study of methane hydrate formation. Chem. Eng. Sci. 38, 1061–1072 (1983).Junhong, Q. & Tianmin, G. Kinetics of methane hydrate formation in pure water and inhibitor containing systems. Chin. J. Chem. Eng 10, 316–322 (2002).Liu, J., Zhou, Y., Sun, Y., Su, W. & Zhou, L. Methane storage in wet carbon of tailored pore sizes. Carbon 49, 3731–3736 (2011).Perrin, A., Celzard, A., Marêché, J. F. & Furdin, G. Methane storage within dry and wet activated carbons: a comparative study. Energy Fuels 17, 1283–1291 (2003).Zhou, L., Liu, L., Su, W., Sun, Y. & Zhou, Y. Progress in studies of natural gas storage with wet adsorbents. Energy Fuels 24, 3789–3795 (2010).Celzard, A. & Marêché, J. F. Optimal wetting of activated carbons for methane hydrate formation. Fuel 85, 957–966 (2006).Webb, E. B. et al. High pressure rheology of hydrate slurries formed from water-in-oil emulsions. Energy Fuels 26, 3504–3509 (2012).Urita, K. et al. Confinement in carbon nanospace-induced production of KI nanocrystals of high-pressure phase. J. Am. Chem. Soc. 133, 10344–10347 (2011).Fujimori, T. et al. Conducting linear chains of sulphur inside carbon nanotubes. Nat. Commun. 4, 2162 (2013).Tse, J. S., Ratcliffe, C. L., Powell, B. M., Sears, V. F. & Handa, Y. P. Rotational and translational motions of trapped methane. Incoherent inelastic neutron scattering of methane hydrate. J. Phys. Chem. A 101, 4491–4495 (1997).Gutt, C. et al. Quantum rotations in natural methane-clathrates from the Pacific sea-floor. Europhys. Lett. 48, 269–275 (1999).Stern, L. A., Kirby, S. H. & Durham, W. B. Peculiarities of methane clathrate hydrate formation and solid-state deformation, including possible superheating of water ice. Science 273, 1843–1848 (1996).Gutt, C. et al. The structure of deuterated methane hydrate. J. Chem. Phys. 113, 4713–4721 (2000).Everett, S. M. et al. Kinetics of methane hydrate decomposition studies via in situ low temperature X-ray powder diffraction. J. Phys. Chem. A 117, 3593–3598 (2013).Miyawaki, J. et al. Macroscopic evidence of enhanced formation of methane nanohydrates in hydrophobic nanospaces. J. Phys. Chem. B 102, 2187–2192 (1998)

Influence of surface wettability on methane hydrate formation in hydrophilic and hydrophobic mesoporous silicas

The methane hydrate MH formation process in confinement was investigated using high pressure methane sorption experiments on two wet materials with similar pore size distributions, B PMO hydrophobic and MCM 41 hydrophilic . Their methane sorption isotherms possess two discrete methane gas consumption steps at 10 bar and 30 bar at 243 K. A systematic analysis reveals that external water and the so called core water inside the pore is rapidly consumed in the first step to form bulk like hydrate, whereas adsorbed water is slowly consumed in the second step to form less stable confined hydrates at higher pressures. Synchrotron powder X Ray results confirm methane hydrate structure I and reveal that bulk ice is swiftly and fully converted to hydrate in MCM 41, whereas inactive bulk ice co exists with MH in B PMO at 6 MPa demonstrating the huge impact of the surface wettability on the water s behavior during MH formatio

Experimental Evidence of Confined Methane Hydrate in Hydrophilic and Hydrophobic Model Carbons

Methane hydrate confined in porous materials is postulated as an alternative energy storage strategy. By applying model carbons with ordered and uniformly sized pores and a combination of advanced in situ characterization techniques, we address fundamental questions on the formation mechanism of methane hydrate in confinement. Here, we provide experimental evidence for the presence of methane hydrate inside confined spaces by in situ small and wide angle neutron scattering, X ray diffraction, and high pressure gas adsorption techniques. Furthermore, we demonstrate how the carbon surface chemistry tremendously impacts the methane hydrate formation kinetics and storage capacity. Our findings represent a substantial step toward transforming a naturally occurring phenomenon into a feasible energy storage technolog