Nickel Phosphides Supported on HZSM-5 for Catalytic Hydrodeoxygenation of Eugenol: Effect of Phosphorus Content

Abstract

Nickel phosphides supported on HZSM-5 zeolite with different initial P/Ni molar ratios were prepared for catalytic hydrodeoxygenation (HDO) of eugenol to produce hydrocarbons. When P/Ni<0.5, the increase of P content gave smaller and more uniform particles which was helpful for hydrogenation of aromatic ring, while the total acid sites of the catalyst decreased due to the coverage of more acid sites of HZSM-5 by adding P which was unfavourable for the removal of oxygen. At P/Ni=0.5, the active phase supported on HZSM-5 was mainly Ni3P with the smallest average particle size and minimum amount of acid sites which could account for the best hydrogenation activity and the lowest selectivity of hydrocarbons, respectively. Further increasing the P/Ni ratio up to 1 and 2, the active phase became Ni2P and a lot of nonuniform Ni2P nanorod crystals appeared on and out of the support HZSM-5 which caused a sharp drop in the hydrogenation activity of the catalyst. For a combination of hydrogenation and deoxygenation considerations, The P/Ni=0.25 is the best ratio for nickel phosphides supported on HZSM-5 zeolite to HDO of lignin-related phenols.