Dong Shu

Enhanced adsorption and photocatalytic activity of BiOI-MWCNT composites towards organic pollutants in aqueous solution

BiOI-MWCNT composites, with high absorption and visible-light photocatalytic performance, were synthesized by a solvothermal process, in which ethylene glycol (EG) participated in the reaction. Synthesized BiOI-MWCNT composites were characterized by X-ray diffraction (XRD), diffuse reflectance spectra (DRS), scanning electronic microscopy (SEM), transmission electron microscopy (TEM), and electrochemical impedance spectroscopy (EIS). The results showed that the prepared BiOI-MWCNT composites exhibit strong adsorption ability with the increase of doped MWCNT amount. The efficiency of AOII degradation increased with the increase of MWCNT amount from 0.5 to 1.0% significantly. The photocatalytic degradation of AOII using BiOI-MWCNT composites under visible light (λ>400 nm) was almost completed within 180 min. BiOI-MWCNT composites maintained its degradation efficiency and durability after being reused for 5 batch runs. The high adsorption ability and degradation efficiency of BiOI-MWCNT for AOII was attributed to the sorption of doped MWCNT and the effective charge transfer from excited BiOI to MWCNTs, respectively. Moreover, organic compounds as intermediates of the degradation process were identified by LC/MS.

Three-dimensional MnO2 porous hollow microspheres for enhanced activity as ozonation catalysts in degradation of bisphenol A

Three-dimensional (3D) MnO2 porous hollow microspheres (δ- and α- MnO2 PHMSs), with high adsorption and catalytic ozonation performance, were synthesized by a self-template (MnCO3 microspheres) process at room temperature. The synthesized MnO2 PHMSs were characterized by X-ray diffraction (XRD), scanning electronic microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) surface area. The results showed that PHMSs exhibit the excellent adsorption ability and catalytic activity owning to their hollow spherical structure, mesoporous shell and well-defined interior voids, leading to the strong adsorption for bisphenol A (BPA) and the retention of O3 molecules on catalyst. Moreover, the catalytic performance of α-MnO2 PHMSs was better than that of δ-MnO2 PHMSs which was attributed to the richer lattice oxygen of α-MnO2 PHMSs to accelerate O3 decomposition by producing more reactive oxidative species. The degradation efficiency of BPA using 3D α-MnO2 PHMSs was more than 90% in the presence of ozone within 30min reaction time. The probe tests for reactive oxidative species (ROSs) displayed that BPA degradation by catalytic ozonation is dominated by O2- and OH in our present study. Furthermore, the organic compounds as intermediates of the degradation process were identified by LC/MS.

Photoelectrocatalytic degradation of organic pollutants in aqueous solution using a Pt-TiO2 film.

A series of Pt- films with nanocrystaline structure was prepared by a procedure of photodeposition and subsequent dip-coating. The Pt- films were characterized by X-ray diffraction, scanning electronic microscope, electrochemical characterization to examine the surface structure, chemical composition, and the photoelectrochemical properties. The photocatalytic activity of the Pt- films was evaluated in the photocatalytic (PC) and photoelectrocatalytic (PEC) degradation of formic acid in aqueous solution. Compared with a film, the efficiency of formic acid degradation using the Pt- films was significantly higher in both the PC and PEC processes. The enhancement is attributed to the action of Pt deposits on the surface, which play a key role by attracting conduction band photoelectrons. In the PEC process, the anodic bias externally applied on the illuminated Pt- films can further drive away the accumulated photoelectrons from the metal deposits and promote a process of interfacial charge transfer.

Preferential catalytic ozonation of p-nitrophenol by molecularly imprinted Fe3O4/SiO2 core-shell magnetic composites

Molecularly imprinted Fe(3)O(4)/SiO(2) core-shell magnetic composites (Fe(3)O(4)/SiO(2)-MIP) were successfully prepared via anchoring p-nitrophenol (p-NP) imprinted functional polymers on the surface of amino-modified Fe(3)O(4)/SiO(2) core-shell particles. Synthesized magnetic Fe(3)O(4)/SiO(2)-MIP composites were characterized by X-ray diffraction, scanning electronic microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and magnetic property measurement. The preferential catalytic ozonation of p-nitrophenol was evaluated in comparison with the competitive reaction in the presence of coexistent phenol. The results showed that the prepared Fe(3)O(4)/SiO(2)-MIP composites exhibit strong adsorption ability due to the strong bonding between p-NP and the molecularly imprinted layer. The Fe(3)O(4)/SiO(2)-MIP demonstrated a preferential catalytic ozonation of p-NP by the recognition ability of the molecularly imprinted layer to the target p-NP. The enhanced catalytic activity using Fe(3)O(4)/SiO(2)-MIP composites could be attributed to the excellent recognition absorption of the MIP layer on the surface of Fe(3)O(4)/SiO(2)-MIP to p-NP.

Heteroaromatic organic compound with conjugated multi-carbonyl as cathode material for rechargeable lithium batteries.

The heteroaromatic organic compound, N,N’-diphenyl-1,4,5,8-naphthalenetetra- carboxylic diimide (DP-NTCDI-250) as the cathode material of lithium batteries is prepared through a simple one-pot N-acylation reaction of 1,4,5,8-naphthalenetetra-carboxylic dianhydride (NTCDA) with phenylamine (PA) in DMF solution followed by heat treatment in 250 °C. The as prepared sample is characterized by the combination of elemental analysis, NMR, FT-IR, TGA, XRD, SEM and TEM. The electrochemical measurements show that DP-NTCDI-250 can deliver an initial discharge capacity of 170 mAh g−1 at the current density of 25 mA g−1. The capacity of 119 mAh g−1 can be retained after 100 cycles. Even at the high current density of 500 mA g−1, its capacity still reaches 105 mAh g−1, indicating its high rate capability. Therefore, the as-prepared DP-NTCDI-250 could be a promising candidate as low cost cathode materials for lithium batteries.

One-step synthesis of silicon carbide foams supported hierarchical porous sludge-derived activated carbon as efficient odor gas adsorbent

Hierarchical porous sludge-derived activated carbon coated on macroporous silicon carbide (SiC) foams substrate has been facilely fabricated via a simple one-step strategy by utilizing sludge as carbon source, and jointly using zinc chloride and hexadecanol as pore forming agents. The sludge-derived carbon has been confirmed to be hierarchical macro-meso-microporous structure based on detailed characterization by scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectra and nitrogen adsorption-desorption measurement. The adsorption tests showed that the hierarchical porous sludge-derived activated carbon fabricated by one-step pore-forming (zinc chloride and hexadecanol microemulsion mixture) possesses excellent adsorption capacity (259.9mgg-1, breakthrough time reach 90min and saturation end-time up to 140min) of methyl mercaptan (CH3SH). The excellent adsorption performance can be attributed to the macroporous SiC foam skeleton and the mesopores channel formed by nonionic surfactant hexadecanol micelles, as well as the micropores activated by ZnCl2 as odor capture sites. The proposed pore-forming strategy paves an avenue for the sludge disposal and even the development of bio-derived materials.

Bio-templated fabrication of three-dimensional network activated carbons derived from mycelium pellets for supercapacitor applications

In this work, a three-dimensional porous mycelium-derived activated carbon (3D-MAC) was fabricated via a facile bio-templating method using mycelium pellets as both the carbon source and the bio-template. After ZnCl2 activation and high-temperature carbonization, the specific thread-like chain structure of mycelium in the pellets can be maintained effectively. The hyphae and junctions of the cross-linking hyphae form nanowires and carbon nanoparticles that link with the neighboring nanoparticles to form a network structure. By adding NH4Cl, foreign nitrogen element doped (N-doped) 3D-MAC was obtained, which has a hierarchical porous structure composed of micropores and macropores. And the multiple pore size distribution benefits from ZnCl2 activation, the specific 3D structure and gas blowing. Meanwhile, the introduction of some hydrophilic groups and abundant N-containing functional groups in extrinsic N-doped 3D-MAC contributes to improving the Faradaic pseudocapacitance, respectively. A specific capacitance of 237.2 F g−1 at 10 mV s−1 was displayed, which is more than 1.5 times that of 3D-MAC. Even at the large scan rate of 500 mV s−1, N-doped 3D-MAC still reveals a nearly symmetric rectangular shape, demonstrating great potential as a high-performance supercapacitor electrode material due to the synergistic effects of its 3D hierarchical porous structure and various functional groups.

Study on degradation of acid orange II in aqueous solution using one-dimensional MnO2 nanorods.

MnO(2) nanorods were prepared by the reaction of KMnO(4) and MnSO(4) in aqueous media and subsequently followed by hydrothermal methods. The structure and surface morphology of as-prepared powder were characterised by X-ray diffraction (XRD) and scanning electron microscopy (SEM). XRD results indicated that the prepared MnO(2) possessed alpha- and gamma structure. SEM observations showed that the obtained MnO(2) powder possessed a well-defined one-dimensional nanorod-like shape 100 nm wide and 700 nm long. The surface area of the MnO(2) nanorods was 92 m(2) g(-1). The degradation efficiency of MnO(2) nanorods towards the organic pollutants in aqueous solution was evaluated using acid orange II as a model dye. It was found that the degradation efficiency of MnO(2) nanorods was a function of initial acid orange II concentration, MnO(2) nanorods concentration, and the proton concentration. The apparent reaction orders for the initial acid orange II concentration, MnO(2) nanorods concentration and the proton concentration were determined to be -0.76, 0.37 and 0.12, respectively. It was found that the degradation efficiency for 60 ppm acid orange II reached 99% with 0.5 g L(-1) MnO(2) nanorods concentration at pH 2.0 after 60 min, demonstrating its higher degradation efficiency in aqueous solution. The apparent activation energy of the degradation reaction of acid orange II was calculated to be 17.3 kJ mol(-1). Furthermore, MnO(2) nanorods were demonstrated to have superior durability during regeneration tests.

Highly Efficient Performance and Conversion Pathway of Photocatalytic CH3SH Oxidation on Self-Stabilized Indirect Z-Scheme g-C3N4/I3–-BiOI

A self-stabilized Z-scheme porous g-C3N4/I3--containing BiOI ultrathin nanosheets (g-C3N4/I3--BiOI) heterojunction photocatalyst with I3-/I- redox mediator was successfully synthesized by a facile solvothermal method coupling with light illumination. The structure and optical properties of g-C3N4/I3--BiOI composites were systematically characterized by means of X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared, X-ray photoelectron spectroscopy, N2 adsorption/desorption, UV-vis diffuse reflectance spectrum, and photoluminescence. The g-C3N4/I3--BiOI composites, with a heterojunction between porous g-C3N4 and BiOI ultrathin nanosheets, were first applied for the photocatalytic elimination of ppm-leveled CH3SH under light-emitting diode visible light illumination. The g-C3N4/I3--BiOI heterojunction with 10% g-C3N4 showed a dramatically enhanced photocatalytic activity in the removal of CH3SH compared with pure BiOI and g-C3N4 due to its effective interfacial charge transfer and separation. The adsorption and photocatalytic oxidation of CH3SH over g-C3N4/I3--BiOI were deeply explored by in situ diffuse reflectance infrared Fourier transform spectroscopy, and the intermediates and conversion pathways were elucidated and compared. Furthermore, on the basis of reactive species trapping, electron spin resonance and Mott-Schottky experiments, it was revealed that the responsible reactive species for catalytic CH3SH composition were h+, •O2-, and 1O2; thus, the g-C3N4/I3--BiOI heterojunction followed an indirect all-solid state Z-scheme charge-transfer mode with self-stabilized I3-/I- pairs as redox mediator, which could accelerate the separation of photogenerated charge and enhance the redox reaction power of charged carriers simultaneously.

Preparation of novel layered AgBr-based inorganic/organic nanosheets by pulsed laser ablation in aqueous media

A novel layered AgBr-based inorganic/organic nanocomposite was prepared by pulsed laser ablation (PLA) of Ag in aqueous media in the presence of cetyltrimethylammonium bromide (CTAB). The obtained AgBr-based inorganic/organic nanocomposite possesses well-defined 2D shape. X-ray diffraction (XRD) pattern was composed of a series of peaks that could be indexed to (00l) reflections of a layered structure, and the basal spacing of 20.0 Å indicated that the surfactant was included between the AgBr interlayers in an interdigitated bilayer arrangement.