Direct Hydrogenolysis of Cellulose into Methane under Mild Conditions

CH4is a clean fuel due to the highest H/C atom ratio among the other hydrocarbon fuels, showing less carbon emission during combustion. The traditional CH4production by fermentation presents the obvious disadvantages of low CH4yield (50–75%) and high CO2emission (25–50%). Herein, an efficient direct conversion of cellulose to CH4was 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 CH4yield of 88.1% was obtained at mild reaction conditions (220 °C and 1 MPa initial H2). This value obtained is the highest yield for the production of CH4from 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 CH4with extreme CO2emission (below 5%) and a better understanding of the cellulose hydrogenolysis process.