Transition metal phosphides, and in particular Ni2P/SiO2, are a new class of catalysts highly active for hydrodesufurization and hydrodenitrogenation reactions of oil fractions. However, the Ni2P/SiO2synthesis temperature is very high for industrial standards (~ 993 K).In this work, different loadings of Pd (0.1, 0.5, 1.0%) were incorporated to a NixPyOz/SiO2 sample aiming the lowering of the transformation temperature phosphate ? phosphide. Temperature-programmed reduction results show that while the reduction profile of the NixPyOz/SiO2 sample presents only one peak with maximum at 993 K, the profile of the sample containing 1% Pd, 1% Pt, or 1% Rh presents such a maximum located at 772 K. The effects of the reduction temperature on the phosphorous K-edge were studied in situ by X-Ray Absorption Near Edge Structure (XANES) also showing, in agreement with TPR results, that the noble metal presence leads to a substantial decrease in the NixPyOz/SiO2 ? Ni2P transformation temperature, as shown in Figure 1.The temperature decrease can be associated with the hydrogen spillover phenomenon that occurs on the noble metal particles giving raise to atomic hydrogen, which greatly reduces the reduction temperature. Thiophene HDS results indicate that after the reduction step, the noble metals do not participate in the reaction.The nature of the spillover phenomen was studied and lead to the conclusion that the noble metal particle has to be in close contact with the phopsphate phase submitted to reduction in order to have a decrease in the synthesis temperature.

Reduction of the synthesis temperature of Ni<sub>2</sub>P/SiO<sub>2</sub> by noble metals addition

248th National Meeting (2014)

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Reduction of the synthesis temperature of Ni2P/SiO2 by noble metals addition

Reduction of the synthesis temperature of Ni₂P/SiO₂ by noble metals addition