One-Pot Synthesis of Active Carbon-Supported Size-Tunable Ni2P Nanoparticle Catalysts for the Pyrolysis Bio-Oil Upgrade.

Catalytic hydrodeoxygenation (HDO) over Ni2P-based catalysts is a promising technology for the pyrolysis bio-oil upgrading. However, substantial challenges still remain in the realization of the size effect for phosphide catalysts in catalyzing this reaction, and the precise size engineering of these catalysts is difficult. In this work, the Ni2P/active carbon (AC) catalysts with varying nickel phosphide nanoparticle sizes were one-pot prepared via the modified organic liquid chemical reaction method. The Ni2P-based catalysts were tested for HDO of the pyrolysis oil model compound (salicylaldehyde), and the conversion of salicylaldehyde first increases and then decreases with the increase of Ni2P nanoparticle size, demonstrating that the activity for HDO of salicylaldehyde can be controlled by using nickel phosphides of varying nanoparticle sizes. The Ni2P-2/AC catalyst with approximately 5.49 nm Ni2P nanoparticle size exhibited the highest activity with conversion of salicylaldehyde reaching over 99% within 180 min under 220 °C, 2 MPa H2 pressure, and the corresponding yield toward o-cresol was over 97%.