Construction of N-substituted pyrrolidones from biomass-derived levulinic acid (LA) via reductive amination is a highly attractive route for biomass valorization. However, realizing this transformation using H2 as the hydrogen source under mild conditions is still very challenging. Herein, we designed porous TiO2 nanosheets-supported Pt nanoparticles (Pt/P-TiO2) as the heterogeneous catalyst. The prepared Pt/P-TiO2 was highly efficient for reductive amination of LA to produce various N-substituted pyrrolidones (34 examples) at ambient temperature and H2 pressure. Meanwhile, Pt/P-TiO2 showed good applicability for reductive amination of levulinic esters, 4-acetylbutyric acid, 2-acetylbenzoic acid, and 2-carboxybenzaldehyde. Systematic studies indicated that the strong acidity of P-TiO2 and the lower electron density of the Pt sites as well as the porous structure resulted in the excellent activity of Pt/P-TiO2.

Transformation of carbon dioxide (CO 2 ) into value-added chemicals is of great importance, and use of natural products as a catalyst is very interesting. Herein, we used the naturally occurring glycine betaine as an efficient and renewable catalyst for the formation of a C−N bond between CO 2 and amines using PhSiH 3 as the reductant. The effects of different factors on the reaction were studied. It was demonstrated that the catalyst was very active for the reactions, and a broad range of amine substrates could be converted with satisfactory yields. Moreover, the selectivity to different N-substituted compounds could be controlled by the molar ratio of reactants (i.e., CO 2 , amines, and PhSiH 3 ) and the reaction temperature. In the catalytic cycle, the carbon oxidation state of CO 2 could be reduced to +2, 0, and −2, respectively, and thus, the corresponding formamides, aminals, and methylamines were produced via successive two-electron reduction steps.

Cleavage of aromatic ether bonds is crucial for the valorization of lignin and its fragments, which is challenging under mild conditions because the bonds are very stable. Herein, we found that Ru/C could efficiently catalyze the cleavage of the aromatic ether bonds in various lignin-derived compounds via a transfer hydrogenolytic route using isopropanol as the hydrogen resource. Various lignin-derived compounds could be efficiently cleaved over commercial Ru/C to generate the corresponding aliphatic alkanes, aliphatic alcohols and aromatic derivatives under milder conditions. A mechanism study indicated that the reaction occurred through the direct cleavage of aromatic ether bonds or the formation of the reaction intermediate cyclohexyl phenyl ether.

Efficient synthesis of primary amines via low-temperature reductive amination of carbonyl compounds using NH3 and H2 as the nitrogen and hydrogen resources is highly desired and challenging in the chemistry community. Herein, we employed naturally occurring phytic acid as a renewable precursor to fabricate titanium phosphate (TiP)-supported Ru nanocatalysts with different reduction degrees of RuO2 (Ru/TiP-x, x represents the reduction temperature) by combining ball milling and molten-salt processes. Very interestingly, the obtained Ru/TiP-100 had good catalytic performance for the reductive amination of carbonyl compounds at ambient temperature, resulting from the synergistic cooperation of the support (TiP) and the Ru/RuO2 with a suitable proportion of Ru0 (52%). Various carbonyl compounds could be efficiently converted into the corresponding primary amines with high yields. More importantly, the conversion of other substrates with reducible groups could also be achieved at ambient temperature. Detailed investigations indicated that the partially reduced Ru and the support (TiP) were indispensable. The high activity and selectivity of Ru/TiP-100 catalyst originates from the relatively high acidity and the suitable electron density of metallic Ru0.

High-performance bifunctional catalysts (Ni–Cu/Al2O3–ZrO2) have been investigated in the selective hydrogenolysis of levulinic acid into 2-methyltetrahydrofuran.

No abstract

The combination of commercial lead dioxide and ionic liquid based catholytes showed highly efficient electrochemical reduction of CO2 into formic acid.

The design and fabrication of eco-friendly, highly efficient, and non-noble-metal-based catalysts are demanding challenges in energy-conversion technologies. Herein, we successfully synthesized CuS nanosheets decorated with CoS2 nanoparticles through a facile route. The optimized 3% CoS2-7% CuS catalysts exhibited remarkable electrocatalytic performance, with excellent cyclic stability at all pH values for the hydrogen evolution reaction (HER). They exhibited lower Tafel slopes (46, 52, and 59 mV dec–1) and smaller overpotentials (62, 85, and 106 mV) at 10 mA cm–2 in 0.5 M H2SO4, 1 M KOH, and 0.5 phosphate buffer aqueous solutions, respectively, than other CoS2/CuS, pure CoS2, and pure CuS catalysts. We attribute their high electrocatalytic performance to their unique heterostructure and the synergistic effects between the constituent metal sulfides that provides a large interfacial contact area, numerous charge-transfer pathways, as well as abundant surface reaction active sites, enhancing the charge-carrier transfer during the HER activity.