Catalytic transfer hydrogenation of bio-oil over biochar-based CuO catalyst using methanol as hydrogen donor

Abstract

The catalytic transfer hydrogenation (CTH) of bio-oil over CuO/PC (porous carbon) with the solid residue produced during biomass pyrolysis as the carrier was investigated with methanol as the hydrogen donor. The effect of carbonization temperature, activation temperature, KOH solution and metal loading on the physicochemical characteristics of CuO/PC catalystand catalytic transfer hydrogenation of bio-oil were investigated. The main alcohols formed in the CTH of bio-oil were 1, 4-butanediol, 1, 3-cyclopentadiol, 1, 3-cyclohexanediol, 2-cyclohexenol and alcohols. It was revealed that more alcohols were produced over CuO/PC using less Cu(NO3)2 than Cu2Al considering their favorable porous system. The well-developed pore structure is formed in PC at a higher calcination temperature and the concentration of activator, which was favorable for the CTH of bio-oil. Under the optimized preparation conditions, the mesopores accounting for 50% in the total pores, achieving the maximized yield of alcohols of 81%, and the well recycling performance was observed with the overall yield of alcohols decreases within 3% after five cycles because of the greater mesopores ratio. The biochar-based PC catalyst in this work enhances the effective usage of biomass to produce alcohols, fully conforming to the theme of energy conservation and low-carbon times.