Excellent cycle stability of Fe loaded on N-doped activated carbon for microwave hydrogenolysis of lignin

[Display omitted] •Fe loaded on activated carbon (Fe/N-AC) is used for microwave hydrogenolysis of lignin.•Bio-oil yield of microwave hydrogenolysis is 40.3 wt%, with phenol selectivity of 38.71%.•Fe/N-AC presents an excellent cycle stability for hydrogenolysis process.•Mechanism of microwave hydrogenolysis in presence of Fe/N-AC are clarified. Microwave-assisted hydrogenolysis of lignin is an emerging alternative to conventional depolymerization capable of converting lignin into aromatic compounds. Activated carbon (AC) supported Fe component have been shown to be cost-effective for this process, but its cycle stability needs to be improved due to Fe agglomeration. Herein, a strategy of nitrogen doping to promote stability was developed, which utilized melamine (C3H6N6) as nitrogen source to prepare the catalyst of N-doped AC supported Fe (Fe/N-AC). The catalyst characterization indicated that the N-doped AC acted as anchor points for Fe components, avoiding catalyst deactivation from the source. Fe/N-AC presented an excellent cycle stability, remaining a phenolic compound selectivity of 93.3 % after five cycles and a decrease of only 4.79 % (compared to the first). The DFT calculation results revealed that Fe/N-AC tended to break CAr-OCH3 during the hydrogenolysis of guaiacol, with an energy barrier of 0.877 eV. This work proposes a simple and effective strategy to improve the stability of lignin hydrogenolysis catalysts, providing important references for the high-valued utilization of lignin.