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Monometallic Pd/C and Re/C and bimetallic Pd−Re/C catalysts with different Re/Pd molar ratios were prepared by incipient-wetness impregnation and characterized by temperature-programmed reduction, X-ray diffraction, CO chemisorption, and transmission electron microscopy. The results indicated that there is a strong interaction between Pd and Re species and that Pd can significantly promote the reduction of rhenium oxide. The hydrogenation of succinic acid to γbutyrolactone and tetrahydrofuran was investigated over the as-prepared Pd/C, Re/C, and Pd−Re/C catalysts. Pd/C showed a low conversion of succinic acid and a high selectivity to γ-butyrolactone. Adding a small amount of Re evidently enhanced the hydrogenation activity of succinic acid and improved the yield of γ-butyrolactone, whereas more Re increased the yield of tetrahydrofuran. The main reaction pathway for the conversion of succinic acid in aqueous solution on Pd−Re/C catalysts is proposed through hydrogenation of the intermediates, including γ-butyrolactone, 1,4-butanediol, and tetrahydrofuran as the substrates.

The removal of C2H2 and C2H6 from C2H4 streams is of great significance for feedstock purification to produce polyethylene and other commodity chemicals but the simultaneous adsorption of C2H6 and C2H2 over C2H4 from a ternary mixture has never been realized. Herein, a robust metal–organic framework, TJT‐100, was designed and synthesized, which demonstrates remarkably selective adsorption of C2H2 and C2H6 over C2H4. Breakthrough experiments show that TJT‐100 can be used as an adsorbent for high‐performance purification of C2H4 from a ternary mixture of C2H2/C2H4/C2H6 (0.5:99:0.5) to afford a C2H4 purity greater than 99.997 %, beyond that required for ethylene polymerization. Computational studies reveal that the uncoordinated carboxylate oxygen atoms and coordinated water molecules pointing towards the pore can trap C2H2 and C2H6 through the formation of multiple C−H⋅⋅⋅O electrostatic interactions, while the corresponding C2H4–framework interaction is unfavorable.

Cleavage of lignin-derived 4-O-5 aryl ethers has been conducted over nickel nanoparticles supported on niobic acid-activated carbon composite under mild conditions. The hydrated niobic acid has been successfully supported and well dispersed on activated carbon. Due to the coexisting Bronsted and Lewis acid sites on the hydrated niobic oxide, the Ni/xNbAC catalysts exhibited higher activities for cleavage of C−O ether bonds and dehydration than those of the Ni/AC catalyst. With increasing content of niobic acid, a larger amount of O-free alkane is obtained owing to niobic acid-promoted removal of oxygen from lignin-derived aryl ethers. The cleavage of C−O ether bonds and dehydration of cyclohexanol to cyclohexane are both favored at high temperature. The direct cleavage of the 4-O-5 aryl ether bond can also be achieved under low H 2 pressure, forming phenol and benzene as intermediates, followed by hydrodeoxygenation of phenol to cyclohexane.