Synthesis and hydrodeoxygenation activity of Ni2P/C – Effect of the palladium salt on lowering the nickel phosphide synthesis temperature

• Pd must be in close contact with phosphate to lower its reduction temperature.
• Lowering phosphate synthesis temperature depends on the salt employed.
• Smaller Pd particles led to better lowering in phosphate reduction temperature.
• Bigger Pd particles increased phosphate’s degree of reduction.
• Pd addition improved nickel phosphide hydrotreating nature in HDO.

The effect of the nature of Pd salt (PdCl2, Pd(NO3)2 or Pd(acac)2) in lowering Ni2P/C synthesis temperature and their effect on guaiacol hydrodeoxygenation reaction were investigated. Pd addition led to a partial lowering of NixPyOz/C (precursor) reduction temperature. For each Pd salt, both the decrease in synthesis temperature and the degree of reduction of NixPyOz were different. While the latter was related to Pd particle size (the bigger the particles were, the higher was the amount of NixPyOz reduced), the former depends both on the contact between Pd and NixPyOz (direct contact is needed) and on Pd particle size (the smaller the particles, the higher the decrease in synthesis temperature). Reaction data revealed that Pd addition suppressed guaiacol hydrogenation. Catalysts characterization revealed that the product distribution was dependent upon the relative proportion on the two types of Ni active sites of Ni2P.

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