Taohai Li

One-step synthesis of Bi2WO6/TiO2 heterojunctions with enhanced photocatalytic and superhydrophobic property via hydrothermal method

A simple hydrothermal method was developed to synthesize Bi2WO6/TiO2-layered heterojunctions. The effect of amount of TiO2 and sodium dodecyl benzene sulfonate, reaction temperature, and reaction time on the structure and morphology of Bi2WO6/TiO2 heterojunctions was investigated. The results suggest that the structure and morphology of Bi2WO6/TiO2 heterojunctions can be tuned by changing reaction conditions. Then the heterojunctions were used to catalyze the degradation of methyl orange, quinoline blue, Rhodamine B, and methylene blue under visible light (Xe-lamp, 300xa0W). And their superhydrophobic property was characterized. It shows that TiO2/Bi2WO6 heterojunctions not only exhibit excellent photocatalytic activity, but also show significant superhydrophobic property. Moreover, a possible photocatalytic mechanism was also proposed.

Preparation of recyclable CdS photocatalytic and superhydrophobic films with photostability by using a screen-printing technique

A PDMS-coated CdS film has been fabricated using a screen-printing technique on common glass without calcination. The as-synthesised CdS film exhibits excellent photostability and enhanced photocatalytic activity for the degradation of some organic pollutants, such as RhB, CB, MB, MO and 2,4-DNP. Above all, the CdS photocatalytic film displayed high stability, recyclability and practicability. In addition, the CdS film possesses superhydrophobic and superoleophilic properties, and could effectively separate the mixture of water and oil. The coatings can clean themselves by the action of water, and have a property of chemically breaking down complex dirt deposits by a sunlight-assisted cleaning mechanism. The simple fabrication process and easy manipulation of the films cleverly combined superhydrophobicity and photocatalysis, and promise practical applications and industrial use of these materials in environmental remediation.

A one-step ionic liquid-assisted ultrasonic method for the preparation of BiOCl/m-BiVO4 heterojunctions with enhanced visible light photocatalytic activity

By combining the advantages of both ionic liquids and ultrasound, a novel method, namely the ionic liquid-assisted ultrasonic method, was developed to prepare BiOCl/m-BiVO4 heterojunctions in several hours at room temperature. Through this method, BiOCl/BiVO4 heterojunctions with different BiOCl contents can be conveniently synthesized via simply changing the amount of 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) used during the preparation process. X-ray diffraction, X-ray photoelectron spectroscopy, and energy-dispersive X-ray spectroscopy were used to examine the structures of the as-prepared BiOCl/m-BiVO4 heterojunctions. The morphologies were characterized via scanning electron microscopy and transmission electron microscopy. The results suggest that the as-prepared BiOCl/m-BiVO4 heterojunctions have high photocatalytic activity and stability for the degradation of Rhodamine B under both visible light and sunlight irradiation at room temperature. Moreover, a possible mechanism was proposed.

Magnetic MoS2 pizzas and sandwiches with Mnn (n=1-4) cluster toppings and fillings: A first-principles investigation

The inorganic layered crystal (ILC) MoS2 in low dimensions is considered as one of the most promising and efficient semiconductors. To enable the magnetism and keep intrinsic crystal structures, we carried out a first-principles study of the magnetic and semiconductive monolayer MoS2 adsorbed with the Mnn (nu2009=u20091–4) clusters, and bilayer MoS2 intercalated with the same clusters. Geometric optimizations of the Mnn@MoS2 systems show the complexes prefer to have Mnn@MoS2(M) pizza and Mnn@MoS2(B) sandwich forms in the mono- and bi-layered cases, respectively. Introductions of the clusters will enhance complex stabilities, while bonds and charge transfers are found between external Mn clusters and the S atoms in the hosts. The pizzas have medium magnetic moments of 3, 6, 9, 4u2009μB and sandwiches of 3, 2, 3, 2u2009μB following the manganese numbers. The pizzas and sandwiches are semiconductors, but with narrower bandgaps compared to their corresponding pristine hosts. Direct bandgaps were found in the Mnn@MoS2(M) (nu2009=u20091,4) pizzas, and excitingly in the Mn1@MoS2(B) sandwich. Combining functional clusters to the layered hosts, the present work shows a novel material manipulation strategy to boost semiconductive ILCs applications in magnetics.

High catalytic active palladium nanoparticles gradually discharged from multilayer films to promote Suzuki, Heck and Sonogashira cross coupling reactions.

To improve the catalytic activity and reduce the dosage of noble metal catalysts has attracted much more attention for organic synthetic chemists. We facilely fabricated multilayer films of PEI-(PdCl2/1)n through layer-by-layer (LBL) self-assembly method (PEI=polyethylenmine, 1=2,2,7,7-tetra(4-pyridyl)-9,9-spirobifluorene, psf). UV-vis spectroscopy, atomic force microscopy (AFM) and scanning electron microscopy (SEM) were used to monitor the growth of multilayer films. X-ray photoelectron spectroscopy (XPS) proved the palladium and ligand 1 were deposited on the film. The PEI-(PdCl2/1)n multilayer films were used as the cisterns of catalysts to gradually discharge high active catalytic moieties in the Suzuki-Miyaura, Heck and Sonogashira cross-coupling reactions. The Pd-loading was as low as 12.1×10(-6)mol% measured by inductively coupled plasma OES spectrometer (ICP), and gave high yields in the typical reactions of bromobenzenes with phenylboronic acids. The LbL catalyst featured the simplicity of fabrication, high efficiency, reusability, convenient control and no sensitive to air in the reactions.

One-pot hydrothermal synthesis of BiVO4 microspheres with mixed crystal phase and Sm3+-doped BiVO4 for enhanced photocatalytic activity

The BiVO4 microspheres and Sm3+-doped BiVO4 polygons were prepared via a facile hydrothermal method by means of K6V10O28·9H2O as a novel vanadium source. Optimized temperature and pH value of prepared BiVO4 were obtained. The polycrystalline BiVO4 microspheres prepared at Txa0=xa0140xa0°C, pH 4, demonstrates the best photocatalytic activities for degrading dyes under UV radiation. This is resulted due to transfers of photogenerated electrons from tetragonal to monoclinic phases. In contrast to the undoped BiVO4, the photocatalytic activity of Sm3+-doped BiVO4 polygons is drastically enhanced not only under UV radiation but also under visible light radiation. The optimized Sm content was found to be 10xa0%. Enhanced efficiency with the doped sample is attributed to the dopants’ role in blocking recombination of photogenerated electron–hole pairs. This work offers a simple route to obtain mixed phase BiVO4 and provide an effective way to achieve higher photocatalytic activity by doping the Sm3+ in the semiconductor catalysts.

Transition Metal Adsorbed-Doped ZnO Monolayer: 2D Dilute Magnetic Semiconductor, Magnetic Mechanism, and Beyond 2D

As an improvement over organic or inorganic layered crystals, the synthetic monolayer ZnO(M) inherits semiconductivity and hostability from its bulk, yet it acts as a promising host for dilute magnetic semiconductors. Here, we report the electronic and magnetic properties of ZnO(M) doped with one 3d transition metal ion and simultaneously adsorbed with another 3d transition metal ion. Two sequences are studied, one where the dopant is fixed to Mn and the adsorbate is varied from Sc to Zn and another where the dopant and adsorbate are reversed. First-principles results show that the stable adsorbed−doped systems possess a lower bandgap energy than that of the host. System magnetic moments can be tuned to |5 – x|μB, where x refers to the magnetic moment of the individual 3d atom. An interplay between superexchange and direct exchange yields a ferromagnetic system dually adsorbed−doped with Mn. In addition to a novel material design route, the magnetic interaction mechanism is found beyond two dimensions, having been identified for its three-dimensional bulk and zero-dimensional cluster counterparts.

Metallic contact between MoS2 and Ni via Au Nanoglue

A critical factor for electronics based on inorganic layered crystals stems from the electrical contact mode between the semiconducting crystals and the metal counterparts in the electric circuit. Here, a materials tailoring strategy via nanocomposite decoration is carried out to reach metallic contact between MoS2 matrix and transition metal nanoparticles. Nickel nanoparticles (NiNPs) are successfully joined to the sides of a layered MoS2 crystal through gold nanobuffers, forming semiconducting and magnetic NiNPs@MoS2 complexes. The intrinsic semiconducting property of MoS2 remains unchanged, and it can be lowered to only few layers. Chemical bonding of the Ni to the MoS2 host is verified by synchrotron radiation based photoemission electron microscopy, and further proved by first-principles calculations. Following the systems band alignment, new electron migration channels between metal and the semiconducting side contribute to the metallic contact mechanism, while semiconductor-metal heterojunctions enhance the photocatalytic ability.

Porous coordination polymer coatings fabricated from Cu3(BTC)2·3H2O with excellent superhydrophobic and superoleophilic properties

A rare example in which the wettability of porous coordination polymer coatings fabricated from Cu3(BTC)2·3H2O was investigated. The sample exhibited excellent superhydrophobicity and superoleophilicity. Furthermore, the superhydrophobic Cu3(BTC)2·3H2O-coated surfaces showed excellent corrosion resistance and long-term stability. These properties make this metal–organic framework (MOF) material attractive for future applications as self-cleaning and oil-absorbing materials.

Shape-controlled hydrothermal synthesis of superhydrophobic and superoleophilic BaMnF4 micro/nanostructures

In this paper, we focus on the controllable synthesis of BaMnF4 micro/nanostructures via a facile one-step hydrothermal method assisted by different surfactants. The chemical structure, morphology and superhydrophobic properties have been studied by XRD, SEM, TEM, EDS and CA. The results show that the pH of the starting solution, temperature, reaction time, and surfactant affect the crystallinity, morphology and superhydrophobic properties of the products. The preliminary reaction path and formation mechanisms of the BaMnF4 with different shapes are also investigated. To the best of our knowledge, the present synthesis route is novel. Furthermore, the as-prepared BaMnF4 surface shows superhydrophobicity and superoleophilicity.