Catalytic hydrodeoxygenation of biomass-derived pyrolysis oil over alloyed bimetallic Ni₃Fe nanocatalyst for high-grade biofuel production

The design of cost-effective and high-performance bimetallic catalysts has become crucial for the effective conversion of biomass-derived pyrolysis-oil (Py-oil) into liquid biofuels. New bimetallic Ni₃Fe catalysts were developed for effective hydrodeoxygenation (HDO) of Py-oil derived from date seeds. Ni₃Fe catalyst showed a well-defined octagon-like morphology with a diameter of 120 nm and high saturation magnetization (Ms) of 78 emu g⁻¹ at room temperature. Py-oil was subjected to catalytic HDO processes at 250 °C for 120 min in a 10 bar H₂ atmosphere in the presence of Ni₃Fe catalyst. Characterization results confirmed HDO of several components of Py-oil, including phenols, acids, aldehyde and ketones, sugars and aromatic hydrocarbons over the surfaces of Ni₃Fe catalyst. The obtained upgraded Py-oil (HDO Py-oil) showed the highest hydrocarbons content of 23.77%, higher heating value (HHV) of 36.78 MJ kg⁻¹, and lower content of water, total acid number, and viscosity than fresh Py-oil. Bimetallic Ni₃Fe catalyst resulted in better HDO performance and re-usability for five consecutive cycles than recently reported monometallic or noble metal nanocatalysts. Plausible reaction pathways for the formation of major components including ethane, ethyl acetate, 2,5-dimethylfuran, D-sorbitol, methylcyclohexane, furfural alcohol, and 1,5-pentane diols are discussed. Results demonstrate that this simple and active bimetallic catalytic system leads to a cutting-edge liquid biofuels production pathway in the future.