Direct Hydrogenolysis of Cellulose into Methane under Mild Conditions

摘要

CH4 is a clean fuel due to the highest H/C atom ratio among the other hydrocarbon fuels, showing less carbon emission during combustion. The traditional CH4 production by fermentation presents the obvious disadvantages of low CH4 yield (50-75%) and high CO2 emission (25-50%). Herein, an efficient direct conversion of cellulose to CH4 was investigated by using several hydrogenation catalysts. The Ru/C catalyst showed the excellent catalytic performance among all the studied catalysts. The optimized reaction parameters including temperature, time, pressure, and catalyst dosage were further investigated by using Ru/C catalyst, and the maximum CH4 yield of 88.1% was obtained at mild reaction conditions (220 degrees C and 1 MPa initial H-2). This value obtained is the highest yield for the production of CH4 from cellulose to date. The reaction network suggests that the hydrolysis, hydrogenation, decarbonylation, retro-aldol reaction, and aqueous-phase-reforming are probably taking place, in which cellulose hydrolysis was proven to be the rate-determined step. This work provided an efficient approach to produce biomass derived CH4 with extreme CO2 emission (below 5%) and a better understanding of the cellulose hydrogenolysis process.