Search

[Display omitted] • 1 wt%Pd/NiMoO 4 with different Pd dispersity were synthesized. • Hydrogen spillover process adjusts hydrogenation sites and acidic sites. • 56.3–84.1% yields of cyclopentanones were obtained over Pd/NiMoO 4 -Cl. • 65.4–85.2% yields of cyclopentanols were generated over Pd/NiMoO 4 -AC. • Adsorption configurations of reactants determine the reaction route. Upgrading bioderived furfurals (furfural, 5-hydroxymethylfurfural) to cyclopentanones (cyclopentanone, 3-hydroxymethylcyclopentanone) and cyclopentanols (cyclopentanol, 3-hydroxymethylcyclopentanol) is a representative bifunctional catalytic process in biomass conversion. Here, a class of Pd/NiMoO 4 catalysts (Pd/NiMoO 4 -Cl, Pd/NiMoO 4 -AC) with low Pd loading (1.0 wt%) and different Pd dispersion are synthesized. The hydrogenation active sites and acidic sites of catalysts were adjusted by a water-mediated hydrogen spillover process. 56.3–85.3% yields of cyclopentanones and 65.4–85.2% yields of cyclopentanols were obtained by hydrogenative ring-rearrangement route of furfurals over Pd/NiMoO 4 -Cl and Pd/NiMoO 4 -AC, respectively. Over-hydrogenated byproducts (tetrahydrofurfuryl alcohol, 2,5-bis(hydroxymethyl)tetrahydrofuran) with a yield above 54% were generated by a full hydrogenation route over Pd/C. The difference in catalytic performance is results from alteration of the adsorption configurations of reactants and the transformation of Lewis acid sites to Brønsted acid sites by hydrogen spillover. This work presents an effective strategy for governing reaction routes and enhancing bifunctional catalysis with a hydrogen spillover mechanism. [ABSTRACT FROM AUTHOR]

Developing a highly selective catalyst to upgrade furfurals (5‐hydroxymethyl furfural and furfural) to cyclopentanones (3‐hydroxymethyl cyclopentanone and cyclopentanone) and tetrahydrofuran alcohols (2,5‐bishydroxymethyl tetrahydrofuran and tetrahydrofuran alcohol) is highly significant for biobased fine chemical synthesis. Here, a series of La2B2O7 (B=Ti, Zr, Ce) metal oxides, featuring the same chemical formula but different topological structures are fabricated. After Pd loading, the Lewis acidity and metal‐support interaction are well governed by the support type, which further affects the hydrogenation and acid‐catalyzed ability. A greater than 82 % yield of cyclopentanones is obtained via a hydrogenative ring rearrangement route over Pd/La2Ti2O7. However, Pd/La2Ce2O7 shows high catalytic efficiency for tetrahydrofuran alcohols with an approximately 80 % yield via a complete hydrogenation route. Additionally, the catalyst exhibits outstanding recycling performance and structural stability. This study presents an interesting design strategy for the selective preparation of cyclopentanones and tetrahydrofuran alcohols through the regulation of the adsorption mechanism. [ABSTRACT FROM AUTHOR]

Herein, novel green synthetic routes to 4-hydroxy-2-cyclopentenone (HCP) and 2-cyclopentenone (CPE) from biomass-derived furfuryl alcohol via double-metal cyanide catalysis are proposed. For the synthesis of HCP, in comparison to conventional solid acids (i.e., Amberlyst-15), MOFs with coordinatively unsaturated metal ions as pure Lewis acid sites exhibit advantageous catalytic selectivity in the reaction under an N2 atmosphere in a bi-phasic water/n-hexane solvent system. FeZn and FeZn-P result in an HCP yield of 77.4% and 88.2%, respectively. For the CPE synthesis, the reaction conditions are the same as those for HCP, except a mono-phasic water solvent system and H2 atmosphere were employed. In addition to the acid-catalyzed rearrangement reaction, FeZn-DMC exhibits catalytic hydrogenation capability via heterolytic cleavage of the H–H bond over Zn–N frustrated Lewis pairs, and a CPE yield of 61.5% is obtained. The DFT simulation indicates that the acid sites and catalytic acid sites are ascribed to the tri-coordinatively unsaturated Zn2+ site (Zn(N)3) on the catalyst surface. Moreover, the DMC catalyst shows excellent stability and recycling performance. This work not only provides an efficient and green catalytic system for CPE and HCP preparation but also demonstrates the interesting bifunctional catalysis of both acid and hydrogenation catalysis over DMC. [ABSTRACT FROM AUTHOR]

Tuning surface properties of electrocatalysts for sustainable electrocatalytic nitrogen reduction reaction (NRR) with high selectivity and activity is highly demanded but still lacks fundamental understanding and modulation methods. Herein, we report the transformation of hydrogen evolution reaction (HER)-favorable cobalt phosphide (CoP) to NRR-favorable electrocatalyst via modulation of surface properties. The oxidized CoP particles encapsulated in carbon nanotubes (O-CoP/CNT) exhibits a high NH 3 yield of 39.58 µg h−1 mg -1 cat as well as high Faradaic efficiency (FE) of 19.4% at −0.5 V vs. reversible hydrogen electrode (RHE), which is confirmed by 15N 2 isotope-labeling tests. In-situ Raman spectra identify that N 2 molecules are preferentially captured by Co ions, while the surface-adsorbed H+ are gradually eliminated. The hydrophobic surface of CNT can limit the contact of protons with the catalyst surface to inhibit HER, and the formation of hydrogen bond facilitates a more efficient NRR process. The surface modulation effects are confirmed by density functional theory calculations. [Display omitted] • Transfermation of HER-favorable CoP to NRR-favorable electrocatalyst. • Reaction intermediates are detected and analyzed by in-situ Raman spectra. • High NH 3 FE and yield are obtained as 19.4% and 39.58 µg h−1 mg -1 cat at −0.5 V. • The essential roles of hydrophobic CNT shell and abundant O-moieties are revealed. [ABSTRACT FROM AUTHOR]

• Pd/Pyrochlore/Al 2 O 3 composites with rich oxygen defects were synthesized. • The oxygen defect promote the selective C O hydrogenation step. • The oxygen defect provide Lewis site for the ring-rearrangement step. • Cyclopentanone motifs can be obtained from furfural derivatives with a yield over 90 %. • ATR-IR results verified the catalytic mechanism. Designing a bifunctional catalyst with both highly selective C O hydrogenation ability and Lewis acid-catalyzed ring-rearrangement ability is highly important for the synthesis of the cyclopentanone motifs from furfural derivatives. Herein, a class of pyrochlore/Al 2 O 3 composites (2.68 wt%Y 2 (Sn 0.65 Al 0.35) 2 O 7-δ /Al 2 O 3, 7.74 wt%Y 2 (Sn 0.65 Al 0.35) 2 O 7-δ /Al 2 O 3) with a onefold Lewis acidity and rich oxygen defects were synthesized via a dissolution-precipitation method. After the impregnation by Pd nanoparticles, the oxygen defect of pyrochlore/Al 2 O 3 shows a bifunctional effect: they can adsorb C O, promoting the selective C O hydrogenation step and can enhance the accessibility of coordinatively unsaturated metal ions, providing Lewis acidic sites for the ring-rearrangement step. The composite-based catalysts show noticeably higher hydrogenation and hydrolysis rates than their corresponding single metal oxide-based catalysts (Pd/Al 2 O 3 , Pd/Y 2 Sn 2 O 7). Finally, 7.74 wt%Y 2 (Sn 0.65 Al 0.35) 2 O 7-δ /Al 2 O 3 shows a cyclopentanone yield of 98.1 % and a 3-hydroxymethyl cyclopentanone yield of 90.6 %. ATR-IR results verify the catalytic mechanism and emphasize the importance of oxygen defects. [ABSTRACT FROM AUTHOR]