The significant promotion of g-C3N4 on Pt/CNS catalyst for the electrocatalytic oxidation of methanol

This article reported a series of g–C₃N₄–CNS (g-C₃N₄ and carbon nanosheets) composite carriers formed by the hydrothermal method, and then the ethylene glycol reduction method was used to anchor Pt nanoparticles on the g–C₃N₄–CNS carrier to form the Pt/g–C₃N₄–CNS catalysts. The electrochemical test for the electrocatalytic oxidation of methanol (MOR) shown that the Pt/20%g–C₃N₄–CNS catalyst has the best catalytic performance and stability. These Pt/g–C₃N₄–CNS catalysts were analyzed by TEM, XRD, XPS, and BET characterization. It is discovered that the amount of g-C₃N₄ greatly influenced the structure and chemical properties of Pt/CNS precursor. As the content of g-C₃N₄ increases, the content of pyridine nitrogen and pyrrole nitrogen also increases, and N species can enhance the interaction between Pt nanoparticles and CNS, promote Pt dispersion, and increase the specific surface area of the catalyst. Similarly, an excessive addition of g-C₃N₄ will cause a sharp decline in the conductivity of the catalyst, and then led to the decline of MOR activity.     

Synthesis and characterization of Pd–ZSM-23 with Na and H form for catalytic hydrodehalogenation of bromobenzene

Ion-exchanged Pd–ZSM-23 (1 wt% Pd) with Na form and H form was well characterized and examined in the hydrodehalogenation of bromobenzene. TPR and XPS results suggested that Pd species dispersed in the different location of ZSM-23. Catalytic test was successfully carried out in mild conditions, using hydrazine hydrate as the hydrogen donor, and no by-products were detected. Recycling test of Pd–NaZSM-23 showed that the catalytic performance did not decrease remarkably until four recycle runs.     

Epoxidation of β-ionone using molecular oxygen over Pt/MCM-41 catalyst under mild conditions

The epoxidation of β-ionone over the Pt/MCM-41 catalyst using molecular oxygen in the liquid phase had been studied. The results indicated that the β-ionone was catalytically oxidized to 5,6-epoxy-β-ionone, 4-oxo-β-ionone, 4-hydroxy-β-ionone and dihydroactinidiolide using molecular oxygen as the sole oxidant. The effects of solvent, content of Pt, reaction temperature and time on the catalytic activity and product selectivity had also been investigated in detail.     

Retracted: Dual Effects of Nanostructuring and Oxygen Vacancy on Photoelectrochemical Water Oxidation Activity of Superstructured and Defective Hematite Nanorods

An Ar atmospheric treatment is rationally used to etch and activate hematite nanoflakes (NFs) as photoanodes toward enhanced photoelectrochemical water oxidation. The formation of a highly ordered hematite nanorods (NRs) array containing a high density of oxygen vacancy is successfully prepared through in situ reduction of NFs in Ar atmosphere. Furthermore, a hematite (104) plane and an iron suboxide layer at the absorber/back‐contact interface are formed. The material defects produced by a thermal oxidation method can be critical for the morphology transformation from 2D NFs to 1D NRs. The resulting hematite NR photoanodes show high efficiency toward solar water splitting with improved light harvesting capabilities, leading to an enhanced photoresponse due to the artificially formed oxygen vacancies.     

Amide–induced monodispersed Pt(100) nanoparticles loaded on graphene surface for enhanced photocatalytic hydrogen evolution

Using free and sustainable solar energy to produce hydrogen is the most promising strategy to resolve the environmental pollution and global energy crisis. The properties of sensitized matrix and co–catalyst, including the dispersibility, lattice structure and electrical performance, are usually two the decisive factors for photocatalytic hydrogen evolution. This paper reports a facile synthetic process of surface–clean monodisperse Pt(100) nanocubes supported on graphene surface using amide functional groups as induction sites. The prepared catalyst (AG/Pt(100)) not only incorporate plentiful amide functional groups that act as the dispersant and stabilizer into surface and edge of graphene, but also significantly dislodge the oxygen–containing functional groups, which hold strong promise for improving conductivity, carrier concentration and mobility of sensitized matrix. Simultaneously, the monodisperse Pt(100) nanocubes supported on graphene surface exposure more active sites. These results provide the necessary conditions for efficient catalysts. Without any pre–treatment, it exhibits high H₂ generation activity (553.7 μmol for 2 h) and apparent quantum efficiency (AQE) (33.9% at 430 nm) under visible light irradiation when Eosin Y is used as photosensitizer. These superior production H₂ activities can attribute to enhance the dispersion and conductivity of sensitized matrix, construct special geometry of Pt(100) nanocubes and prolong the lifetime of photogenerated electron.     

Rubidium hydrazinidoborane: Synthesis,characterization and hydrogen release properties

In this work we present rubidium hydrazinidoborane RbN₂H₃BH₃ (RbHB), the newest and last member of the alkali metal derivatives of hydrazine borane N₂H₄BH₃ (HB). It is shown that HB readily reacts with metallic rubidium in THF at room temperature to form RbHB under argon atmosphere. The molecular and crystal structures of this new compound are discussed on the basis of FTIR spectroscopy, ¹¹B MAS NMR spectroscopy, and powder X-ray diffraction analyses. RbHB crystallizes in a monoclinic P2₁ (No. 4) unit cell where each Rb⁺ cation adopts octahedral coordination surrounded by six [N₂H₃BH₃]⁻ anions, which are two more than for e.g. LiN₂H₃BH₃ (with tetrahedral coordination) in accordance with the larger size of Rb⁺. RbHB is isostructural to potassium hydrazinidoborane KN₂H₃BH₃. Its dehydrogenation properties, evaluated by using thermogravimetric analysis, differential scanning calorimetry, and isothermal analysis, are compared to those of the parent HB as well as to analogous compounds in order to evaluate the potential of RbHB as hydrogen storage material. According to the presented data, the dehydrogenation properties of RbHB are much better than those of HB and are comparable to those of the lithium derivative. Our main results are reported therein.     

Electrodeposited Pt nanorods on a novel flowered-like nanostructured NiCo alloy as an electrocatalyst for methanol oxidation

For the first time, a novel system of Pt nanorods supported on nano flowered-like structure NiCo alloy has been successfully electro-synthesized onto a glassy carbon electrode for the electrocatalytic oxidation of methanol. The electrodeposited system has been characterized using scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). The electrocatalytic efficiency of the electro-fabricated system of Pt/NiCo/GCE have been confirmed by cyclic voltammetric (CV) and current-time methods. It is discovered that the electrodeposited nano flowered NiCo alloy substrate has a great effect on the electrocatalytic properties of the electrodeposited Pt nanorods. The electrocatalytic efficiency of the new system for methanol oxidation reaction (MOR) is found to be 174 A/g_Pt. The effect of electrodeposition time for NiCo alloy has been studied. Also, the effect of pH, temperature, and concentration for the electrodeposition of Pt catalyst on the electrocatalytic properties of the Pt/NiCo/GCE have been studied for detection the optimum conditions. The mechanism of the electrocatalytic oxidation of methanol has been discussed. Furthermore, the stability and the corrosion resistance test of the Pt/NiCo/GCE system have been investigated by electrochemical impedance spectroscopy (EIS), Tafel plot and current-time methods.     

Epoxidation of Butadiene Over Nickel Modified TS-1 Catalyst

Abstract  

Nickel modified Titanium silicalite 1 (TS-1) catalysts provided an environmentally benign and effective method for butadiene epoxidation. Certain loading of modified Ni in our system significantly promoted TS-1 catalytic activity. The product vinyloxirane (VO) was obtained with high yield of 0.49 mol/L (theoretic equilibrium value 0.52 mol/L). The turnover number (TON, determined as the molar VO obtained per molar Ti atom) reached 1,140. Besides, the catalyst kept high activity during five runs of reusability test. XRD, N₂ adsorption and desorption, TPR, XPS, FT-IR and DR UV–Vis were employed to characterize the specific Ni role to Ti-site in Ni/TS-1 catalysts.     

Preparation and characterization of graft copolymer from dealkaline lignin and styrene

Graft copolymerization of styrene onto dealkaline lignin by ferrous chloride and hydrogen peroxide coinitiator has been achieved successfully. The influence of temperature and reaction time as well as the amount of the styrene monomer, initiator, and catalyst on the grafting copolymerization was investigated. The optimum reaction conditions were determined as follows: c (styrene) = 20.00 mmol, c (H₂O₂) = 5.00 mmol, c (FeCl₂) = 0.10 mmol, T = 30°C and t = 48 h. The optimum yield (Y), total conversion (TC), grafting efficiency (GE), and degree grafted (DG) values were 96.6, 96.3, 59.5, and 53.7%, respectively. The copolymer of lignin grafted PS was separated and characterized by elemental analysis, differential scanning calorimetry, Fourier transform infrared, thermogravimetry analysis, field emission‐scanning electron microscopy, gel permeation chromatography, and nuclear magnetic resonance. It was demonstrated that the solubility what the copolymer exhibited turned out to be the very reverse of the original lignin. The surface properties and structure of lignin were completely changed after grafting copolymerization. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41900.