Hydrodeoxygenation of Lignin–derived Diaryl Ethers to Aromatics and Alkanes Using Nickel on Zr–doped Niobium Phosphate
4-O-5 diaryl ether owns the strongest aryl−aryl ether bond of the abundant Caryl−O bonds in lignin. Selective hydrodeoxygenation (HDO) of diaryl ethers to oxygen-free aromatics and alkanes has been achieved over nickel nanoparticles supported on Zr-doped niobium phosphate solid acids in an autoclave under the mild conditions. Py-IR, NH3-TPD and TEM techniques were conducted to investigate the surface acidity and metal particle distribution of as-synthesized catalysts. Nickel on Zr-doped niobium phosphate exhibited an excellent activity for 84 % conversion of diaryl ether and a better selectivity of oxygen-free aromatic about 62 % and the total HDO selectivity reached up to 92 % at 220 oC and 0.5 MPa, which is attributed to the favorable synergetic catalytic effect between acid sites and metal sites. In addition, higher reaction temperature favors the production of oxygen-free aromatics and alkanes and low H2 pressure is benefit for formation of benzene.