Fe-modified MoS2/NC catalyst for hydrodeoxygenation of lignin into aviation fuel-range arenes
Lignin, as the sole renewable source of aromatic compounds, holds significant potential for producing green aviation fuel-range arenes via hydrodeoxygenation (HDO). In this study, a series of nitrogen-doped carbon-supported FeMoS/NC bimetallic catalysts were synthesized via a hydrothermal method. The HDO performance was evaluated using 4-ethylguaiacol as a model compound at 340 °C under 3 MPa H2. The unmodified MoS2/NC catalyst achieved a deoxygenation degree of 83.4%, whereas the Fe-modified catalyst with an optimal Fe/Mo molar ratio of 0.3 (Fe0.3MoS/NC) attained complete deoxygenation (100%) with an arenes selectivity of 78.6%. Beyond this optimal ratio, the deoxygenation degree inversely correlated with the Fe/Mo molar ratio. Characterization via XRD, TEM, BET, and XPS revealed that Fe incorporation enhanced the uniform dispersion of MoS2 on the NC support, increased surface acidity, and raised the concentration of sulfur vacancies, thereby promoting adsorption of oxygen-containing compounds. The HDO pathway over Fe0.3MoS/NC primarily proceeded via direct deoxygenation. When applied to real lignin under identical conditions (340 °C, 3 MPa H2, 12 h), the catalyst yielded 65.5% green hydrocarbons, with the C8–C16 fraction accounting for 54.4% of total hydrocarbons and an aromatic selectivity of 63.4% within this fraction. These results demonstrate that Fe0.3MoS/NC is a viable catalyst for selective conversion of lignin into green arenes suitable for sustainable aviation fuel applications.