Catalytic Cleavage of the C–O Bonds in Diphenyl Ether over a High-Performance Ni–Ru Bimetallic Solid Superacid Catalyst

Selective hydrogenolysis of C–O bonds in lignin is widely regarded as the most promising strategy for generating high-value chemicals and clean liquid fuels. Ni–Ru bimetallic catalyst supported on solid superacid was successfully synthesized and applied to the cleavage of C–O bonds in diphenyl ether (DPE) and alkali lignin. The catalytic hydrogenolysis of DPE over a 10%Ni–0.5%Ru–S2O82–/ZrO2 catalyst produced 88.0% cyclohexanol. Additionally, 10%Ni–0.5%Ru–S2O82–/ZrO2 catalyzed the depolymerization of alkali lignin in high yields of phenolic compounds, primarily including guaiacol and methoxyphenol. The synergistic effect between Ni and Ru promoted electron transfer from Ni to Ru. The incorporation of Ru improved the dispersion of Ni and reduced the average particle size of metallic Ni. The strong acidity of the solid superacid support provided abundant acidic sites, facilitating hydrogen atom adsorption and thereby promoting C–O bonds cleavage.