Nitrogen-doped carbon supported iron nanoparticles for mild catalytic hydrocracking of Xilinguole lignite.

[Display omitted] • Fe/NC catalyst shows good activity and stability for cleaving C-O bonds in lignite. • Fe-N and Fe/Fe 3 C species in the catalyst were crucial to the catalytic activity. • Active hydrogen species were hydrogen radicals generated from H 2 and isopropanol. • The hydrocracking products have higher H/C ratio and heating values than lignite. • Catalytic hydrocracking promoted producing phenols via the cleavage of C-O bonds. Cleaving C-O bridged bonds of lignite via catalytic hydrocracking (CHC) is an effective method to produce chemicals and clean fuels. Herein, a nitrogen-doped carbon supported Fe catalyst was developed by using a one-pot method for CHC of Xilinguole lignite (XL) and its related model compounds. The doped nitrogen enhanced the interaction between Fe and N species to form Fe-N sites and favored forming smaller Fe/Fe 3 C nanocrystals, which played a crucial role in CHC performance. Toluene and phenol were produced from CHC of benzyl phenyl ether (BPE) with high yield and selectivity at 250 °C over the optimal catalyst with 4% Fe, without hydrogenation products. The Fe-based catalyst activated both H 2 and isopropanol to generate hydrogen radicals for cleaving C-O bridged bonds. The CHC of XL under different temperature and time showed that the yields of oil, asphaltene and preasphaltene were obviously promoted under 325 °C, 1 MPa, and 6 h, and they had much higher H/C ratio but remarkably lower O/C ratio, resulting in much higher heating values (28.19–36.90 MJ/kg) than XL. Phenols were the major group component with relative content of 53.6 wt% in oil from CHC, and the asphaltene and preasphaltene from CHC had obviously lower molecular weights, which could attributed to depolymerization of C-O bridged bonds in the XL macromolecular structures over the catalyst. [ABSTRACT FROM AUTHOR]