Fig. 3: Structural characterization and Raman spectra analysis.
From: Rapid conversion of amino acid modified-ice to methane hydrate for sustainable energy storage
a PXRD pattern of ice made from pure water and 3000 ppm tryptophan solution (tryptophan AM-Ice). The International Centre for Diffraction Data entry (ICDD ID: 00-042-1141), corresponding to Ice Ih, is included for comparison. b PXRD pattern of methane hydrate synthesized using tryptophan AM-Ice (3000 ppm tryptophan). The Crystallography Open Database entry (COD ID: 96-901-2469), representing sI hydrate, is included for comparison. c Raman spectra of methane hydrate synthesized from tryptophan AM-Ice (3000 ppm tryptophan) and non-modified ice. The Raman spectra are obtained at atmospheric pressure, free from signal interference caused by methane gas. The yellow rectangle highlights the C–H stretching region of CH4, while the gray rectangle indicates the O–H stretching region of H2O. d Peak fitting and deconvolution for the Raman spectra obtained for methane gas at 6 MPa and methane hydrate synthesized from tryptophan AM-Ice (3000 ppm tryptophan).
