Catalysis Science & Technology最新文献

Palladium-catalyzed organic transformations play a crucial role in organic synthesis, serving as vital tools for synthesizing significant classes of molecules and biologically active compounds. However, palladium, being a noble metal, has limited sources, posing sustainable challenges. DNA, known as the molecule of life, provides excellent opportunities for interaction with metals due to the nucleobases and phosphate groups present in its structure. DNA-supported palladium catalysts have demonstrated efficient catalytic activities across a diverse range of reactions, including cross-coupling, carbonylative cross-coupling, hydrogenation, oxidation, and imination reactions, for the synthesis of important classes of compounds such as acids, amides, biphenyls, alkynes, amines, and enaminones. The beneficial impact of DNA support on the reactivity and recyclability of palladium has been substantiated for sustainability issues.

The diffusion in ZSM-5 zeolite of methanol and of two series of promoters of the methanol to dimethyl ether reaction (linear methyl esters, benzaldehyde, 4-n-alkyl benzaldehydes) has been studied using classical molecular dynamics in the NVT ensemble. Whereas promoter diffusion coefficients decrease with increasing alkyl chain length in methyl esters, the aromatic aldehyde promoters all have similar diffusion coefficients. The lowest diffusion coefficient is that of benzaldehyde. All the promoters exhibit a preference for moving in the straight pore, a preference that is most pronounced for the 4-n-alkylbenzaldehydes and least for the longest aliphatic esters. A novel diffusion mechanism, a molecular ‘3-point turn’, is observed. This likely plays an important role in allowing the most potent promoters, with longer linear alkyl chains, to access all of the Brønsted acid reaction sites. The diffusion coefficient of methanol is larger than that of all the promoters. The more catalytically active aromatic aldehyde promoters limit methanol diffusion less than the aliphatic esters.

Herein, we show that [Cp*Co(2-ampy)I]I (2-ampy = 2-aminomethyl-pyridine) is an extremely active catalyst for HER, exhibiting a TOF of 109 000 s⁻¹ in phosphate buffered water solution (pH 7). The key to this remarkable activity stems from the establishment of a network of weak interactions in the second coordination sphere. As a matter of fact, both experimental and theoretical studies strongly suggest that the –NH₂ functionality of the 2-ampy ligand acts as an anchoring and orienting group for H₂PO₄⁻ through the establishment of an intermolecular hydrogen bonding with it that, in turn, intermolecularly donates a proton to Co–H liberating H₂.

The potential of hydrogen production via water splitting technology makes it urgent to develop low-cost and highly active bifunctional catalysts for hydrogen and oxygen evolution reactions (HER/OER). In this study, a low platinum (Pt) bimetallic phosphide heterostructure (Pt-NiFe-P/NF), derived from three-dimensional NiFe metal–organic framework (NiFe-MOF) nanorods on nickel foam (NF), was developed using a two-step hydrothermal and phosphorization process. The nickel-iron phosphide nanorod array heterostructure boasts a large surface area with numerous active sites, which enhances charge and substance transfer. The integration of metallic Pt with NiFe-P heterostructures subtly adjusts the electronic redistribution between them, thereby improving the kinetics of water splitting. Consequently, the Pt-NiFe-P/NF catalyst demonstrated exceptional HER and OER performance in a 1 M KOH solution, with overpotentials of 97 and 266 mV at 100 mA cm⁻², respectively. Remarkably, an electrolyzer utilizing this catalyst requires just a 1.65 V potential to achieve a current density of 100 mA cm⁻², exceeding the capabilities of conventional Pt/C||RuO₂ systems, which require 2.10 V and outperforming many advanced electrochemical water splitting catalysts currently in use.