Chemistry - An Asian Journal最新文献

Electrocatalytic oxidation of biomass molecules such as ethanol in hybrid alkaline water electrolysis is more thermodynamically favorable and techno-economic attractive to replace conventional pure water electrooxidation to produce green hydrogen. Herein, the flexible and binder-free hollow microtube catalyst arrays of CoS₂/CC, Ni_0.04Co_0.96S₂/CC, Fe_0.07Ni_0.04Co_0.89S₂/CC, and Fe_0.08Ni_0.10Co_0.82S₂/CC were derived from metal-organic framework arrays anchored on carbon cloth (CC). These arrays exhibited favorable performance in electrochemical water oxidation, ethanol oxidation, and hydrogen evolution processes, because of their obvious advantages in high conductivity and long-term stability. The optimized self-supporting Fe_0.08Ni_0.10 Co_0.82S₂/CC electrode composed of a 3D hollow porous microtube structure only needs a low potential of 1.412 and 1.267 V (vs. RHE) to deliver 10 mA cm⁻² current density for alkaline water and ethanol oxidation reactions, respectively. Simultaneously, the pure CoS₂/CC electrode presents excellent alkaline hydrogen production property among the series self-supporting electrodes with a low overpotential of 188 mV at 10 mA cm⁻². In this work, it is proved that the hybrid water splitting system, using Fe_0.08Ni_0.10Co_0.82S₂/CC and CoS₂/CC as anode and cathode, respectively, can effectively reduce the cell voltage to 1.479 V to deliver 10 mA cm⁻² with high pure hydrogen generation and high valued potassium acetate generation.

Bifunctional electrocatalysts for overall water splitting (OWS) is critical for sustainable hydrogen production but remains challenging due to the sluggish kinetics and leaching of metal ions. Herein, we present a kind of phosphorus and molybdenum codoped ruthenium and ruthenium oxides heterostructure (P,Mo_0.1-Ru/RuO₂) as a highly efficient bifunctional electrocatalyst for alkaline OWS. The incorporation of P facilitates the electron transfer from P to Ru, leading to the partial reduction of RuO₂ to metallic Ru. Moreover, the reduced oxidation of Ru suppresses the dissolution of RuO₂, favoring the structural stability. In alkaline media, P,Mo_0.1-Ru/RuO₂ demonstrates enhanced hydrogen evolution and oxygen evolution activities, requiring overpotentials of only 61 and 230 mV, respectively, to achieve a current density of 10 mA cm⁻². When employed as anode and cathode for OWS, the P,Mo_0.1-Ru/RuO₂ catalyst enabled a low cell voltage of 1.50 V at 10 mA cm⁻², along with an enhanced electrochemical stability. These results highlight the synergistic effect of anion and cation codoping in enhancing electrocatalytic performance, offering a promising strategy for the design of advanced bifunctional catalysts for sustainable hydrogen production.

An efficient Rh(III)-catalyzed pivaloyl-directed strategy has been developed for the C7_Ar-(acyl)alkylation of tryptophans with substituted and unsubstituted allyl alcohols, delivering tryptophan-based unnatural amino acids without compromising their chirality. The disclosed methodology showcased high tolerance of neutral, acidic, and basic amino acids, including Gly, Ala, Val, Leu, Phe, Pro, Asp, Lys, and Thr units, enabling regioselective late-stage functionalization of tryptophan units in a variety of tryptophan-containing dipeptides, tripeptides in reasonable yields.

In this study, a hierarchical porous (HP) Al₂O₃/HP-UiO-66 composite was prepared via a facile template and solvothermal strategy. The material exhibits a high adsorption capacity for phosphate, with a maximum theoretical value of 303 mg/g based on the Langmuir model—eight times greater than that of the original UiO-66. It also displays excellent selectivity for phosphate over common ions in domestic wastewater, along with a wide pH stability range (2–10) and rapid adsorption equilibrium, reaching saturation within 90 min. Moreover, the composite maintains over 85% of its adsorption efficiency after six cycles. These results demonstrate that Al₂O₃/HP-UiO-66 possesses enhanced adsorption capacity, faster kinetics, improved acid–base resistance, and superior selectivity, highlighting its potential for effective phosphate removal from wastewater.

The first examples of covalently linked, β-meso-phenyl ethyne bridged dyads 1–6 containing 14π triphyrin(2.1.1)/metallotriphyrin, and 18π porphyrin/metalloporphyrin subunits were synthesized in decent yields. The free base 14π triphyrin(2.1.1)–18π porphyrin(1.1.1.1) dyad 1 was prepared by Sonogashira cross coupling of β-monobromo triphyrin(2.1.1) 7 and 5-[4-ethynylphenyl]-10,15,20-tri(p-tolyl) porphyrin 8 in toluene/TEA at 40°C for 12 h. The triphyrin(2.1.1)–metalloporphyrin dyads 2, 3, and 4 were obtained by treating free base dyad 1 with NiCl₂, CuCl₂, and Zn(CH₃COO)₂ salts, respectively, in CHCl₃/CH₃OH at reflux, whereas metallotriphyrin–metalloporphyrin dyads 5 and 6 were synthesized by reacting dyads 2 and 4, respectively, with Re(CO)₅Cl in toluene/TEA under refluxing conditions. Dyads 1–6 are very unique and contain two different types of aromatic conjugated macrocycles, such as contracted 14π triphyrin(2.1.1) and regular 18π porphyrin(1.1.1.1), having different properties. The absorption and the electrochemical studies supported weak interactions between the subunits in dyads 1–6. The density functional theory (DFT) studies revealed that in dyads 1–6, the triphyrin(2.1.1)/metallotriphyrin and porphyrin/metalloporphyrin units were oriented with a dihedral angle in the range of 24°–65° with respect to each other.

Lithium–sulfur batteries are promising for meeting growing global energy needs and supporting sustainable development. However, the shuttle effect is a key barrier to their wide use. Reducing Li⁺ ion solvation is an effective solution. In this study, adiponitrile (ADN), featuring two highly electronegative cyano groups, forms a stable [Li(ADN)]⁺ complex that contracts the solvation shell of Li⁺. Its moderate molecular size also helps form a denser interfacial protective film on the sulfur cathode, boosting surface stability. Density functional theory (DFT) simulations show ADN's cyano groups bind strongly to Li⁺, forming stable local structures that suppress polysulfide migration and improve cycle stability. Experimentally, batteries with ADN retain 75% of initial capacity after 120 cycles at 0.2 C and have a 744 mAh g⁻¹ discharge capacity at 2 C. X-ray photoelectron spectroscopy (XPS) confirms ADN-Li⁺ interaction and reveals ADN's role in regulating the electrolyte's solvation environment. This work provides new insights for electrolyte design in next-generation Li–S batteries.

Reductive hydrofunctionalization of 1,3-dienes by transition-metal/SiH catalysis has emerged as a promising strategy for the rapid construction of molecular complexity from simple precursors. However, previous reports have predominantly focused on branched-selective 1,2-hydrofunctionalization pathways. Herein, we describe a reductive 1,2-hydrovinylation of 1,3-dienes with vinyl triflates that proceeds with exclusive linear selectivity. This transformation establishes a new selectivity paradigm in transition-metal/SiH catalysis, wherein a Ni–C insertion pathway overrides the classical Ni–H insertion process, enabled by the synergistic cooperation between NiBr₂ and a CF₃-substituted PyrOX ligand. The reaction features a broad substrate scope, encompassing a wide range of aryl and heteroaryl 1,3-dienes as well as both cyclic and acyclic vinyl triflates.

A metal-free selective selenylation and sulfonylation of 1,7-dienes with selenosulfonates for divergent synthesis of seleno-/sulfonyl-benzoxepines has been developed. This reaction was conducted under mild conditions without any catalysts, oxidants, or additives. The choice of solvent plays a crucial role in determining the formation of seleno-/sulfonyl-benzoxepines. Preliminary mechanistic studies suggest that both the selenylation and sulfonylation are accomplished through a selenyl radical and a sulfonyl radical cyclization process.