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Currently, low intimacy between hydrogenation sites and acidic sites causes unsatisfactory catalytic activity and selectivity for the synthesis of 2,5‐hexanedione from C6 furan aldehydes (5‐methylfurfural, 5‐hydroxymethylfurfural). Herein, iodine(I) modification of Pd‐supported catalysts (such as PdI/Al2O3 and PdI/SiO2) was investigated to modulate the hydrogenation sites and acidic sites. Unlike Pd catalysts that produced 71.4 % yield of 2‐hydroxymethyl‐5‐methyl tetrahydrofuran via an overhydrogenation route of 5‐methylfurfural, PdI catalysts showed a high efficiency for 2,5‐hexanedione with 93.7 % yield by a hydrogenative ring‐opening route. More importantly, the selective synthesis of 2,5‐hexanedione from 5‐hydroxymethylfurfural with a high yield of 50.2 % by the hydrogenolysis and subsequent ring‐opening route was reported for the first time. I‐modified Pd nanoparticles produced in‐situ hydrogen spillover, which promoted the selective C=O hydrogenation and ring‐opening steps by regulating the adsorption configuration of the reactants and the transformation of Lewis to Brønsted acidity, respectively. [ABSTRACT FROM AUTHOR]

Electroreduction of N2 to NH3 at ambient conditions using renewable electricity is promising, but developing efficient electrocatalysts is still challenging due to the inertness of N≡N bonds. Layer double hydroxides (LDHs) composed of first‐row transition metals with empty d‐orbitals are theoretically promising for N2 electroreduction (NRR) but rarely reported. Herein, hollow NiCo‐LDH nanocages with different Ni/Co ratios were prepared, and their electronic structures and atomic arrangements were critical. The synergetic mechanisms of Ni and Co ions were revealed, and the optimized catalytic sites were proposed. Besides, in‐situ Raman spectroscopy and 15N2 isotopic labeling studies were applied to detect reaction intermediates and confirm the origin of NH3. As a result, high NH3 yield of 52.8 μg h−1 mgcat−1 and faradaic efficiency of 11.5 % were obtained at −0.7 V, which are top‐ranking among Co/Ni‐based NRR electrocatalysts. This work elucidates the structure–activity relationship between LDHs and NRR and is instructive for rational design of LDH‐based electrocatalysts. [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]