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Hexagonal ultrathin nanoplates of basic lead carbonates were synthesized in aqueous lead acetate solution under ambient conditions. The sizes of the nanoplates were found to reach several hundreds of nanometers to micrometers, whereas the plate thickness was only several nanometers, corresponding to 3, 4, or 5 stacking layers along the c-axis. These nanoplates exhibited effective catalytic properties for the hydrogenation of nitroarenes, such as nitrobenzene, 4-nitroaniline, and 4-nitrophenol, and other organic dyes, such as methylene blue and methyl orange in aqueous solutions in the presence of KBH4. Pb nanoclusters were generated in situ during the catalytic process and were well dispersed on the surface of the nanoplates, leading to the formation of a zero-dimensional/two-dimensional (0D/2D) heterostructure. It was also found that the heterostructure exhibited different catalytic behaviors for the hydrogenation of the compounds mentioned above due to the different molecular structures and different adsorption and desorption abilities of the reactants and products. Such a heterostructure can be also anticipated to be an effective photocatalyst due to its strong UV-light absorption, the ultrathin characteristics of the highly crystalline nanoplates and the transfer abilities of the Pb nanoparticles. [ABSTRACT FROM AUTHOR]

An environmentally benign synthesis of natural benzaldehyde from cinnamaldehyde under mild conditions has been investigated with sodium hypochlorite as oxidant and β-cyclodextrin polymer as phase-transfer catalyst. The polymer showed excellent catalytic activity exhibiting 92% conversion and 62% selectivity to benzaldehyde at ambient pressure and at 70°C. This catalyst could be recovered and reused six times, and the catalyst efficiency remained unchanged, which suggests that the catalyst is an efficient and green catalyst for oxidation of cinnamaldehyde. The results reported herein may be a promising method in industry for the synthesis of natural benzaldehyde. [ABSTRACT FROM PUBLISHER]

Two-dimensional helical nanowire and nanosphere superstructures of PS- b -P2VP/S-mandelic acid with homochirality have been fabricated at the liquid/liquid and air/liquid interfaces via two kinds of approaches, respectively. [Display omitted] • PS-b-P2VP co-assembled with S-mandelic acid in the liquid/liquid interfacial phase. • Helical nanowires and nanospheres with homochirality formed. • These nanowires and nanospheres further assembled into 2D superstructures. • This is a one-step method to fabricate 2D superstructures of helical nanostructures. Chiral supramolecules have attracted great research interest due to their unique properties and functions. How to assemble them into the ordered superstructures, however, remains a challenge. In this paper, two methods have been developed to fabricate such superstructures. In method I, polystyrene- b -poly (2-vinylpyridine) (PS- b -P2VP) and S-mandelic acid (S-MA) diffused from the oil and aqueous phases respectively to the oil/water interface, combined and self-assembled into helical nanowires and nanospheres with monochirality, and formed parallel-aligned nanowire arrays and close-packed arrays at the liquid/liquid interface. In method II, PS- b -P2VP in DMF droplets was introduced into the aqueous solution of S-MA through a liquid/liquid interfacial phase transfer process. Then the polymer molecules self-assembled into helical nanowires and nanospheres with monochirality in the aqueous phase, which adsorbed at the air/liquid interface and organized into superstructures. The formation of chiral aggregates should be attributed to the induction of S-MA, while the superstructures at the interfaces were considered to result from the modulation by the interfacial pressures. This study has developed one-step techniques to assemble the chiral aggregates and superstructures, which is expected to become universal for fabrication of functional superstructures. [ABSTRACT FROM AUTHOR]

A variety of supramolecular structures of benzene-1,3,5-tricarboxamide derivatives (BTAs), such as helixes and nanosheets, have been fabricated. However, how to regulate the self-assembly behavior through molecular design and control of experimental conditions, and thus to form supramolecular structures with different morphologies is still a topic that needs to be further explored. In this paper, two kinds of BTAs with different end groups, i.e. terpyridine and carboxyl were synthesized, which are referred to as L and A, respectively. Their self-assembly behaviors in DMF/aqueous solution were investigated by adding the DMF solution of BTAs into the aqueous solution dropwise. It was found that the two BTAs exhibited different self-assembly behaviors. L self-assembled into helical nanowires and nanosheets in the mixed media at lower and higher metal ion concentrations. However, A formed multilayer vesicles and nanotubes at lower and higher concentrations of A molecules. Such a difference was ascribed to their different molecular structures and therefore the different amphiphilicity. The more hydrophobic L molecules could escape from DMF droplets and self-assembled with the help of supramolecular interactions. The more amphiphilic A molecules were prone to adsorb at the oil/water interface to form layered films. The relative strength of coordination interaction determined the self-assembly behavior of L and the formation of helical nanowires and nanosheets, and the packing mode of A molecules at the oil/water interface determined the formation of vesicles and nanotubes. In addition, the formed vesicles of A were responsive to pH. [Display omitted] • BTAs with end groups of terpyridine and carboxyl are referred to L and A molecules. • The self-assembly behaviors of L and A in mixed DMF/aqueous solutions were studied. • L self-assembled into helical nanofibers and nanosheets. • A self-assembled into multilayer vesicles and nanotubes. • The self-assembly behaviors are related to molecular structure and conditions. [ABSTRACT FROM AUTHOR]

Ellipsoidal and spherical superstructures, network structure and hierarchical structure of noble metal spherical or rod-like nanoparticles were fabricated through a liquid/liquid interface mass transfer-assisted self-assembly process in aqueous solutions. • A general approach has been developed to fabricate superstructures of nanoparticles. • A liquid/liquid interface mass transfer process was used to introduce amines into hydrosols. • The fatty amines combined with colloidal particles and organized into superstructures. • Ellipsoidal and spherical superlattices of spherical nanoparticles were obtained. • Network and hierarchical structures of nanospheres and nanorods were obtained. Organized assemblies of noble metal nanoparticles (NPs) exhibit unique optical, electronic and catalytic properties and potential applications in various areas. Many kinds of methods have been developed to fabricate such functional systems. In this work, we report a facile and novel method to fabricate the organized aggregates of Au and Ag NPs. Their freshly prepared hydrosols were used as upper phase, and the DMF/chloroform solutions of different fatty amines were used as bottom phases to form a planar liquid/liquid interface. The mass transfer across the interface occurred immediately, where the DMF droplets containing fatty amines entered into the hydrosols, leading to the formation of organized aggregates of NPs through a self-assembly process of amine molecules. It was found that several kinds of assemblies were generated, including ellipsoidal and spherical superstructures of spherical NPs, networks of spherical NPs and nanorods, and hierarchical structure of nanorods. In addition, networks composed of Au NPs/Ag skeleton satellite-core type nanorods were further constructed, which exhibited good catalytic performance and SERS property. [ABSTRACT FROM AUTHOR]

Exploitation of earth-abundant, cost-effective and high-efficient bifunctional electrocatalysts for overall water spitting in basic media is highly desirable, yet it remains a big challenge. Here, NiFe Layered-double-hydroxide nanosheet-anchored CoSe nanotubes (composed of plicated nanosheets) supported on Ni foam are prepared through our developed hydrothermal-selenization-hydrothermal method. Benefiting from the unique nanoarchitecture, optimized adsorption/desorption of oxygenated species at the interface (owing to the re-delocalization of electron spin status via π-donation), the bifunctional hybrid catalysts exhibit low overpotentials of 201 and 98 mV at 10 mA cm−2 for oxygen evolution reaction and hydrogen evolution reaction in 1 M KOH aqueous solution, respectively. Particularly, the full-cell only requires 1.53 V to drive a current density of 10 mA cm−2 when choosing the hybrid catalysts serving as both anode and cathode, being superior than that of the state-of-the-art commercial noble-metal based cells for overall water splitting. This work presents a general strategy to boost the oxygen evolution reaction and hydrogen evolution reaction kinetics of selenides, which is also expected to extend to other noble-metal-free catalysts. Image 1 • A three-step strategy was developed for synthesis of CoSe@NiFe-LDH electrocatalyst. • Re-localization of electron spin status was occurred at the interface. • The constructed full-cell requires 1.53 V to drive a current density of 10 mA cm−2. • CoSe@NiFe-LDH electrocatalysts exhibit both splendid OER and HER activities. [ABSTRACT FROM AUTHOR]

We report a new 2D layer-like network composed of Co 7 cluster-containing sandwich-type polyoxometalate, Li 10 Na 2 [Co(H 2 O) 3 (CH 3 COO)] 2 {[Co 7 (H 2 O) 4 (OH) 2 (Ale) 2 ][PW 9 O 34 ] 2 }·20H 2 O ( 1 ) {H 5 Ale = Alendronic acid}, which was synthesized by the conventional aqueous solution method. Single-crystal X-ray diffraction analysis reveals that 1 crystallizes in the monoclinic P 2(1)/n space group with unit cell a  = 12.5391 (1) Å, b  = 25.2531 (2) Å, c  = 22.0462 (2) Å, β  = 97.728(1)°, Z  = 2, V  = 6917.55 (10) Å 3 . This compound was further characterized by powder X-ray diffraction (PXRD), IR spectra and thermogravimetric (TG) analyses to confirm its structure and composition. As a result, polyoxoanion in 1 consists of two { A -PW 9 O 34 } 9− units, which are fused together by a {Co 7 (H 2 O) 4 (OH) 2 (Ale) 2 } { Co 7 } cluster into a sandwich-type structure. In the { Co 7 } cluster, all the Co 2+ ions are connected together by two Ale ligands and two OH groups into the hepta-nuclear cobalt cluster { Co 7 }. Further, the sandwich-type polyoxoanions are connected together by two {CH 3 CO 2 Co(H 2 O) 3 } units, resulting in the first 2D layer-like structure consisting of Co 7 -containing sandwich polyoxoanion. Electrochemical and electrocatalytic studies reveal that 1 exhibits good electrocatalytic activity toward the reduction of H 2 O 2 in neutral aqueous solution. [ABSTRACT FROM AUTHOR]

Abstract: Regular one-dimensional (1D) parallel chains composed of CdS nanoparticles with cubic zinc blende crystal structure were prepared at the air/water interface via one-step synthesis and assembly process. These nanostructures were produced through an interfacial reaction between Cd2+ ions in the aqueous solution of cadmium acetate and H2S in the gaseous phase under Langmuir monolayers of 10,12-pentacosadiynoic acid (PDA). It was demonstrated that PDA molecules self-assembled into parallelly aligned linear supermolecules at the air/water interface with the aid of π–π interactions and acted as templates for the formation of the superstructures. The experimental conditions including temperature and reaction time have great influences on the superstructure formation and the parameters of the parallel chains. [Copyright &y& Elsevier]

The composite poly(2-vinylpyridine) (P2VP)-Ag纆like thin films were prepared at the interface between AgNO3aqueous solution and polymer chloroform solution at 25 °C. An X-ray photoelectron spectroscopy (XPS) investigation indicated that Ag誉 in the composite films were partially transformed to Ag atoms after irradiated by UV-light and completely transformed to Ag atoms after being treated with KBH4aqueous solution. Ag nanoparticles with the average sizes of 2.71 ± 0.82 and 3.28 ± 1.20 nm were generated in these two transferred films with different treatments, respectively. Transmission electron microscopy (TEM) and high-resolution TEM (HRTEM) images showed clearly that the composite films were composed of microcapsules whose walls had multilayer structures, and the nanoparticles were incorporated in the walls. The formation of the composite films at the liquid–liquid interface was attributed to the adsorption of the polymer molecules at the interface, coordination between the pyridine groups and Ag誉, and self-assembly of the composite molecules. Furthermore, the catalytic activity of the composite films was evaluated using the reduction of 4-nitrophenol (4-NP) by KBH4. The results demonstrated that the composite thin films have high and durable catalytic activity. [ABSTRACT FROM AUTHOR]