LAUSR

Abstract Five different unsupported transition metal phosphides were synthesized and tested for hydrodeoxygenation of phenol in gas phase at 300 °C and atmospheric pressure. The metal phosphide phases were synthesized in two steps: synthesis of phosphates and temperature programmed reduction. In situ X-ray diffraction and temperature programmed reduction revealed the formation of the phosphide phases: Ni2P, MoP, CoP/CoP2, FeP and WP. The in situ diffractograms showed that the metal phosphate precursor is decomposed during reduction, producing metal oxide (Molybdenum) or pyrophosphate (Nickel, Iron) phases, without the formation of a metallic phase. All catalysts showed high selectivity to direct deoxygenation products, indicating that the phosphide phases promoted the direct cleavage of C O bond. However, product distribution varied significantly depending on the metal phosphide phase. Ni2P catalyst exhibited the highest selectivity to benzene, whereas CoP, FeP and WP showed a significant formation of cyclohexene. FeP also produced cyclohexane, while a large amount of C5 – C6 hydrocarbons was formed over MoP. Product distribution was correlated to the type of crystal structure of transition metal phosphides.