Synthesis of open-mouthed,yolk–shell Au@AgPd nanoparticles with access to interior surfaces for enhanced electrocatalysis

We have successfully produced open-mouthed, yolk–shell (OM-YS) Au@AgPd nanoparticles (NPs) via galvanic replacement reaction at room temperature; each NP has a large opening on its AgPd shells. Owing to the openings on the AgPd shells, the inner surfaces of the AgPd shells of as-prepared OM-YS Au@AgPd NPs become accessible to the surrounding media. These new structural characters make the present OM-YS Au@AgPd NPs excellent catalysts for electrochemical oxidation of ethanol in alkaline media. Their electrochemical active surface area is 87.8 m² g^–1 and the mass activity is 1.25 A mg_Pd^–1. Moreover, the openings on the AgPd shells also make the surfaces of the Au cores in OM-YS Au@AgPd NPs accessible to the reaction media, which significantly facilitates the removal of CO and other carbonaceous intermediate species, thus leading to substantially enhanced durability and stability. This superior electrocatalytic performance cannot be implemented by using conventional YS Au@AgPd NPs or commercially available Pd/C catalysts.     

A three‐dimensional anionic metal–dicyanamide network in poly[ethyltriphenylphosphonium [tri‐μ2‐dicyanamidato‐cadmium(II)]]

The title compound, (C₂₀H₂₀P)[Cd(C₂N₃)₃], consists of ethyltriphenylphosphonium (EtPh₃P⁺) cations filling voids in a three‐dimensional anionic cadmium dicyanamide network. In the structure, each Cd^II atom is connected to six neighbouring Cd^II atoms through six separate dicyanamide ligands, forming cube‐shaped cages. The three‐dimensional anionic network encloses a solvent‐accessible void space of 1851 ų, amounting to 69.3% of the unit‐cell volume. Each cage accommodates only one EtPh₃P⁺ cation.     

Surfactant-Free and Controlled Synthesis of Hexagonal CeVO4 Nanoplates: Photocatalytic Activity and Superhydrophobic Property

Nanomaterials with both superhydrophobic surface properties as well as photocatalytic activities could have important industrial applications. Herein, we synthesized CeVO₄ nanocrystals with hexagonal nanoplate structures from the reaction of decavanadate (K₆V₁₀O₂₈⋅9 H₂O) and CeCl₃⋅H₂O precursors via a hydrothermal method. This synthetic route has four advantages: 1) the reaction condition is relatively mild, 2) it doesn′t need surfactants or templates, 3) it requires no expensive equipment, and 4) products are of higher purity. During synthesis, solution pH, and reaction temperature were found to play important roles in determining the growth process and final morphologies of the CeVO₄ products. These products were characterized spectrophotometrically and via scanning and transmission electron microscopy. Furthermore, the wettability of the as-synthesized film CeVO₄ nanoplates was studied by measuring water contact angle (CA). The largest CA measured was at 169.5 ° for a glass substrate treated with 0.06 g mL⁻¹ CeVO₄ followed by 2 % 1 H, 1 H, 2 H, 2 H-perfluorodecyltriethoxysilane. Finally, the CeVO₄ nanoplates exhibited excellent photocatalytic activity in degradation of rhodamine B (RhB) under UV irradiation and was stable even after repeated cycles of use.     

Comparison of Nitrogen Activation on Trinuclear Niobium and Tungsten Sulfide Clusters Nb3Sn and W3Sn (n=0–3): A DFT Study

The reaction of N₂ with trinuclear niobium and tungsten sulfide clusters Nb₃S_n and W₃S_n (n=0–3) was systematically studied by density functional theory calculations with TPSS functional and Def2-TZVP basis sets. Dissociations of N−N bonds on these clusters are all thermodynamically allowed but with different reactivity in kinetics. The reactivity of Nb₃S_n is generally higher than that of W₃S_n. In the favorite reaction pathways, the adsorbed N₂ changes the adsorption sites from one metal atom to the bridge site of two metal atoms, then on the hollow site of three metal atoms, and at that place, the N−N bond dissociates. As the number of ligand S atoms increases, the reactivity of Nb₃S_n decreases because of the hindering effect of S atoms, while W₃S and W₃S₂ have the highest reactivity among four W₃S_n clusters. The Mayer bond order, bond length, vibrational frequency, and electronic charges of the adsorbed N₂ are analyzed along the reaction pathways to show the activation process of the N−N bond in reactions. The charge transfer from the clusters to the N₂ antibonding orbitals plays an essential role in N−N bond activation, which is more significant in Nb₃S_n than in W₃S_n, leading to the higher reactivity of Nb₃S_n. The reaction mechanisms found in this work may provide important theoretical guidance for the further rational design of related catalytic systems for nitrogen reduction reactions (NRR).     

The Comparative Study of Reaction Mechanisms and Catalytic Performances of Cu–SSZ-13 and Fe–SSZ-13 for the NH3-SCR Reaction

Catalysis Surveys from Asia - The catalytic performances and mechanism differences of model catalysts Cu–SSZ-13 and Fe–SSZ-13 with similar metal content and Si/Al ratio were compared....     

Responsive hyperbranched poly(formyl-1,2,3-triazole)s toward quadruple-modal information security protection

Science China Chemistry - Secrecy has received tremendous attention in modern information society. Innovative polymer-based fluorescent materials with multiple mode emission are quite desirable to...     

Neutral 1D Perovskite-Type ABX3 Phase Transition Material with a Narrowband Emission and Semiconductor Property

Cyclic organic amines are emerging as excellent building blocks to assemble organic–inorganic hybrid phase transition materials due to their flexible cyclic structure. Here, we have assembled a 1D organic-inorganic hybrid dielectric material C₅H₆NOPbBr₃ ( 1 ) by alloying the cyclic organic amine 3-hydroxypyridine. 1 displays a remarkable switchable dielectric response induced by an order-disorder transformation of the organic moiety, this transformation behaviour is confirmed by DSC and Hirshfeld surface measurements. More interestingly, 1 has a narrowband emission (FWHM=4.64 nm) at 590 nm; FWHM is a major quality figure for narrowband photodetectors. In addition, 1 exhibits semiconducting properties with an indirect bandgap of 2.78 eV by the analysis of the UV-Vis absorption results.     

An Electrochemical Way to Generate Amphiphiles from Hydrazones for the Synthesis of 1,2,4-Triazole Scaffold Cyclic Compounds

An electro-oxidative cyclization pathway in which hydrazones are selected as starting materials to generate amphiphiles by reacting with benzylamines and benzamides was reported. This strategy successfully prepared a series of 1,2,4-triazoles in satisfactory yields. Moreover, the use of cheap stainless steel as the anode, the feasibility to conduct the transformation as a one-pot reaction and the proof that scaling-up these reactions is possible make this transformation attractive for potential application in industry.     

FeO(OH)@C-Catalyzed Selective Hydrazine Substitution of p-Nitro-Aryl Fluorides and their Application for the Synthesis of Phthalazinones

An efficient hydrazine substitution of p-nitro-aryl fluorides with hydrazine hydrates catalyzed by FeO(OH)@C nanoparticles is described. This hydrazine substitutions of p-nitro-aryl fluorides bearing electron-withdrawing groups proceeded efficiently with high yield and selectivity. Similarly, hydrogenations of p-nitro-aryl fluorides containing electron-donating groups also smoothly proceeded under mild conditions. Furthermore, with these prepared aryl hydrazines, some phthalazinones, interesting as potential structures for pharmaceuticals, have successfully been synthesized in high yields.     

Controlled electropolymerization based on self-dimerizations of monomers

Electropolymerization is one of the most important methodologies to synthesize and develop conducting polymers. The complexity of the polymerization mechanism, ion doping processes and structural defects are considered to be symbiotic and unavoidable, making the stagnant state and huge band gap with advanced interdisciplinary research fields and important applications in the last three decades. Herein, we provide a point of view into controlled electropolymerization by regioselective activation reactions of monomers, where self-dimerizations instead of self-electropolymerizations were utilized. The resulting dimers play a role in the connections between functional building blocks to form functional polymers on demand. This account highlights the typical findings in controlled electropolymerizations as a forum for discussing new opportunities in exploiting novel designs and applications.