Catalytic Complete Cleavage of C–O and C–C Bonds in Biomass to Natural Gas over Ru(0)

Being the naturally abundant renewable resource, biomass plays a significant influence on the energy landscape. The transformation of renewable biomass into natural gas is particularly fascinating but remains challenging due to the structural complexity. Here, we developed a catalytic strategy for the high-efficiency transformation of lignocellulosic biomass into natural gas through the complete cleavage of C–O and C–C bonds over Ru(0). X-ray photoelectron spectra showed that Ru atoms were reduced to the metallic state. Moreover, Ru(0) facilitated the catalytic cleavage of C–O and C–C bonds in the biomass. For isosorbide with various C–O and C–C bonds, the gas carbon yield reached up to 93.5% with 85.4 mol % of CH4 and 7.1 mol % of C2–C4 hydrocarbons in gas carbon product distribution, and the turnover frequencies were up to 206.8 h–1. The further conversion of raw biomass was investigated to obtain 90.0 mol % of CH4 in gas products. Investigation on the reaction pathway revealed that the vicinal hydroxyl group was the fundamental prerequisite for the catalytic cleavage of the C–C bond. Moreover, the cleavage of the C–C bond adjacent to the secondary hydroxyl group was much more difficult than that of the primary hydroxyl group which revealed the low energy barrier for the catalytic cleavage of C–O and C–C bonds. Thus, the stepwise cleavage of the C–C bond adjacent to the primary hydroxyl group might be the main contribution to the catalytic transformation of the biomass into natural gas.