Influence of the oxygen-containing surface functional groups in the methane hydrate nucleation and growth in nanoporous carbon

Petroleum pitch-derived activated carbon (PP-AC) has proved to be an excellent platform to promote the methane hydrate formation in milder condition than nature, even though the water-to-hydrate yield at the threshold formation pressure of 3.3 MPa is rather low (ca. 13%). Herein, we report that the presence of oxygen-containing surface functional groups in the oxidized carbon analogue (PP-AC_Ox) plays a significant role in the nucleation and growth in the low-pressure region. High-pressure methane adsorption/desorption isotherms revealed an enhancement in the water-to-hydrate yield up to ca. 51% around 3.3 MPa and 2 °C, in an extremely narrow working pressure window, with no hysteresis associated.