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Herein, we describe a AuPd catalyst for selective and solventless conversion of ethyl levulinate (EL) and amines to pyrrolidones under ambient pressure. The optimized Au66Pd34 nanoparticle catalyst was stable and reusable over 10 runs. AuPd catalysis was extended to reductive amination of levulinic acid and 4-acetylbutyric acid, providing a green chemistry approach under milder conditions not only to pyrrolidones, but also to piperidines, both of which are important scaffolds in designing polymers, natural products and pharmaceuticals. [ABSTRACT FROM AUTHOR]

Using nanoparticles (NPs) to catalyze multiple chemical reactions in one-pot and to achieve high-yield syntheses of functional molecules/materials is an important direction in NP chemistry, catalysis and applications. In this article, we report a nanocomposite of AgPd NPs anchored on WO2.72 nanorods (NRs) (denoted as AgPd/WO2.72) as a general catalyst for formic acid dehydrogenation and transfer hydrogenation from Ar-NO2 to Ar-NH2 that further reacts with aldehydes to form benzene-fused heterocyclic compounds. The AgPd/WO2.72 catalysis is Ag/Pd dependent and Ag48Pd52 is the most active composition for the multiple chemical reactions. The high activity of AgPd/WO2.72 arises from strong interfacial interaction between AgPd and WO2.72, resulting in AgPd lattice expansion and electron polarization from AgPd to WO2.72. The syntheses proceed in one-pot reactions among formic acid, 2-nitrophenol (or 2-nitroaniline, or 2-nitrothiophenol) and aldehydes in dioxane/water (2/1 v/v) at 80–90 °C, leading to one-pot syntheses of benzoxazoles, benzimidazoles and benzothiazoles that are key ring structures present in functional compounds for pharmaceutical, optical and polymer applications. [ABSTRACT FROM AUTHOR]

The demand for nylon-66 has sharply increased in industry because of its high mechanical strength, high rigidity, and excellent stability. The deep hydrogenation of adiponitrile (ADN) to 1,6-hexanediamine (HDA) is considered as a crucial step to produce nylon-66 in industry. Herein, we report a diffusion strategy to prepare surface Pd-rich PdAg nanowires (NWs) via a seed-mediated growth in polyol solution for efficient dehydrogenation catalysis of formic acid (FA) and subsequent hydrogenation of ADN by using FA as an in situ hydrogen source. The composition of surface Pd-rich PdAg NWs could be easily tuned by controlling the amounts of the precursors. And the surface Pd-rich Pd5Ag5 NWs exhibit the highest activity for dehydrogenation catalysis of FA with an initial TOF of 1600 h−1 and a highly efficient hydrogenation of ADN to HDA with 99% selectivity and 99% conversion at 50 °C. Their enhanced catalytic performance could be attributed to the Pd-rich surface of the NWs and more efficient electron transfer from Ag to Pd. This work demonstrates a new way to prepare surface Pd-rich Pd5Ag5 NWs for deeply hydrogenating ADN to HDA with FA as an in situ hydrogen source. [ABSTRACT FROM AUTHOR]

A comprehensive strategy has been developed to synthesize highly ordered mesoporous Nafion membranes with different structure symmetries including 2D hexagonal (2D-H), 3D face-centered (3D-FC), 3D cubic-bicontinuous (3D-CB) and 3D body-centered (3D-BC), using a soft template method with the assistance of a silica colloidal mediator. The Nafion membrane derived from the self-assembled mesoporous Nafion–silica composites maintained the microstructures of the silica framework, which was confirmed by small angle X-ray scattering (SAXS) and TEM. The in situ time-resolved synchrotron SAXS clearly indicates that the presence of silica colloids is critical for the formation of the highly ordered mesoporous structured phase in the precursor solution. The best results are observed on Nafion membranes with 2D-H structure in terms of proton conductivity and cell performance under reduced relative humidity (RH) conditions, achieving proton conductivities of 0.08, 0.062 and 0.038 S cm−1 at 100, 40 and 0%RH, respectively. Moreover, the power output of the mesoporous Nafion membrane cells show a S-shaped dependence on RH and are stable under anhydrous conditions (i.e., 0% RH), demonstrating the outstanding high water retention capability of the mesoporous structure of the membranes. [ABSTRACT FROM AUTHOR]

Highly ordered and periodic mesoporous Nafion membranes with controlled structural symmetries including 2D hexagonal, 3D face-centered, 3D cubic-bicontinuous and 3D body-centered have been successfully synthesized by a novel colloidal silica mediated self-assembly method with high proton conductivity particularly under conditions of low humidity. [ABSTRACT FROM AUTHOR]

Among metals used for CO 2 electroreduction in water, Cu appears to be unique in its ability to produce C2+ products like ethylene. Bimetallic combinations of Cu with other metals have been investigated with the goal of steering selectivity via creating a tandem pathway through the CO intermediate or by changing the surface electronic structure. Here, we demonstrate a facile cation exchange method to synthesize Ag/Cu electrocatalysts for CO 2 reduction using Cu sulfides as a growth template. Beginning with Cu 2- x S nanosheets (C-nano-0, 100 nm lateral dimension, 14 nm thick), varying the Ag + concentration in the exchange solution produces a gradual change in crystal structure from Cu 7 S 4 to Ag 2 S, as the Ag/Cu mass ratio varies from 0.3 to 25 (CA-nano- x , x indicating increasing Ag fraction). After cation exchange, the nanosheet morphology remains but with increased shape distortion as the Ag fraction is increased. Interestingly, the control (C-nano-0) and cation exchanged nanosheets have very high faradaic efficiency for producing formate at low overpotential (-0.2 V vs. RHE). The primary effect of Ag incorporation is increased production of C2+ products at -1.0 V vs. RHE compared with C-nano-0, which primarily produces formate. Cation exchange can also be used to modify the surface of Cu foils. A two-step electro-oxidation/sulfurization process was used to form Cu sulfides on Cu foil (C-foil- x ) to a depth of a few 10 s of microns. With lower Ag + concentrations, cation exchange produces uniformly dispersed Ag; however, at higher concentrations, Ag particles nucleate on the surface. During CO 2 electroreduction testing, the product distribution for Ag/Cu sulfides on Cu foil (CA-foil- x-y ) changes in time with an initial increase in ethylene and methane production followed by a decrease as more H 2 is produced. The catalysts undergo a morphology evolution towards a nest-like structure which could be responsible for the change in selectivity. For cation-exchanged nanosheets (CA-nano- x ), pre-reduction at negative potentials increases the CO 2 reduction selectivity compared to tests of as-synthesized material, although this led to the aggregation of nanosheets into filaments. Both types of bimetallic catalysts are capable of selective reduction of CO 2 to multi-carbon products, although the optimal configurations appear to be metastable., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)