The limited supply of fossil fuels and the impact of rising CO₂ emissions make the development of fuels from renewable resources an important research goal. The most abundant resource for such applications is lignocellulosic biomass. It can be converted to bio-oil by flash pyrolysis. However, this bio-oil has a high oxygen content and needs to be modified further to give hydrocarbons which can be used as fuels. Commonly, catalytic hydrodeoxygenation reactions are used to achieve this.

Shik Chi Edman Tsang, Dermot O’Hare, University of Oxford, UK, and colleagues have developed an efficient catalyst for hydrodeoxygenation based on highly dispersed palladium and molybdenum phosphate nanoparticles. The team prepared an aqueous solution containing (NH₄)₆Mo₇O₂₄•4 H₂O, (NH₄)₂HPO₄, PdCl₂, citric acid, and HCl. This solution was added to SiO₂, which acts as a support for the catalyst. The resulting material was calcined and finally reduced using H₂ to give the catalyst.

The researchers used the conversion of phenol to cyclohexane as a test reaction for the catalyst and found conversion rates of up to 100 % and selectivities of up to 97.5 %. The catalyst also showed good performance for the conversion of water-insoluble bio-oil derived from wood and bark. According to the team, the performance of the material can be attributed to a synergy between highly dispersed palladium, Brønsted-acidic sites, and Lewis-acidic sites in the catalyst.

• Hydrodeoxygenation of water-insoluble bio-oil to alkanes using a highly dispersed Pd–Mo catalyst,
  Haohong Duan, Juncai Dong, Xianrui Gu, Yung-Kang Peng, Wenxing Chen, Titipong Issariyakul, William K. Myers, Meng-Jung Li, Ni Yi, Alexander F. R. Kilpatrick, Yu Wang, Xusheng Zheng, Shufang Ji, Qian Wang, Junting Feng, Dongliang Chen, Yadong Li, Jean-Charles Buffet, Haichao Liu, Shik Chi Edman Tsang, Dermot O’Hare,
  Nat. Commun. 2017.
  DOI: 10.1038/s41467-017-00596-3