Synthesis of highly active carbon-encapsulated NiP catalysts by one-step pyrolysis-phosphidation for hydrodeoxygenation of phenolic compounds

Hydrodeoxygenation (HDO) of phenolic compounds is a promising technology to convert biomass materials to value-added chemicals and fuels. However, the development of highly efficient catalysts remains a great challenge. In this work, a facile one-step pyrolysis-phosphidation strategy for the synthesis of carbon-encapsulated nanostructured Ni 2 P@C( x ) catalysts ( x is the initial mass ratio of NaH 2 PO 2 to Ni-MOF-74) under a N 2 atmosphere from a metal-organic framework (Ni-MOF-74) was proposed and the prepared catalysts were used for HDO of phenol. The effects of different values of x and reaction conditions on the phenol HDO performance as well as product distribution were investigated. The results showed that as compared to the Ni@C catalyst (4.2%), the de-oxygenated product selectivity was enhanced 22.8 times by the introduction of the P species due to the promoted dehydration of cyclohexanol over Ni 2 P@C( x ) catalysts. Ni 2 P@C(3) exhibited the best catalytic performance at the temperature of 250 °C, pressure of 2 MPa, and reaction time of 2 h; the conversion of phenol was 100%, and the total yield of deoxygenated products reached 100%. The HDO of phenol over the Ni 2 P@C( x ) catalyst mainly proceeded via the HYD pathway (hydrogenation of the aromatic ring to cyclohexanol, and dehydration of cyclohexanol to give rise to cyclohexene followed by hydrogenation to cyclohexane). The deoxygenation selectivity over Ni 2 P@C( x ) was enhanced 22.8 times as compared to the Ni@C catalyst due to addition of P species.