Chun-Bo Liu

Syntheses, structures and photoluminescence of a series of metal-organic complexes with 1,3,5-benzenetricarboxylate and pyrazino[2,3-f][1,10]-phenanthroline ligands

A series of new metal-organic coordination complexes, [Co2(HBTC)2(Pyphen)2(H2O)4]·4H2O (1), [Mn(HBTC)(Pyphen)(H2O)] (2), [Cd2(OH)(BTC)(Pyphen)2]·H2O (3), [Cu2(OH)(BTC)(Pyphen)] (4), and [Zn2(OH)(BTC)(Pyphen)] (5) were prepared through hydrothermal reactions of pyrazino[2,3-f][1,10]-phenanthroline (Pyphen) and 1,3,5-benzenetricarboxylic acid (H3BTC) with different metal salts. All these compounds were structurally determined by X-ray single-crystal diffraction. In the dinuclear Co(II) compound (1) π–π interactions exist between Pyphen and HBTC2− ligands, resulting in interesting 2D supramolecular layers. For complex (2), the Mn(II) centers are linked by HBTC2− ligands to form a 2D (4,4) coordination layer, and these layers are interdigitated in pairs. Polymer (3) also possesses a 2D network structure composed of the tetrametallic clusters [Cd4(µ2-OH)2], which is extended to 3D arrays through the π–π interactions between Pyphen ligands. The isostructural coordination polymers (4) and (5) show the same 3D framework structure. Solid-state luminescent spectra of the Cd(II) and Zn(II) complexes indicate intense fluorescent emissions.

Fabrication of TiO2–BiOCl double-layer nanostructure arrays for photoelectrochemical water splitting

A novel TiO2–BiOCl double-layer nanostructure array (rutile nanowires@anatase/BiOCl nanosheets) was successfully designed and prepared. The obtained samples were systematically characterized by scanning electron microscopy, X-Ray diffraction, the UV–Vis diffuse reflectance spectra, Raman spectroscopy, photocurrent versus potential (I–V) curves, and the incident photon to current efficiency (IPCE) curves. According to the photoelectrochemical data, the introduction of the BiOCl nanosheet on the TiO2 nanowire film could markedly enhance the photocurrent and IPCE value, due to the formation of TiO2/BiOCl heterostructures on the FTO substrate. Furthermore, the sample exhibits the best photoelectrochemical performance when the depositing cycle of BiOCl is 60 times.

Highly emissive Zn–Ln metal–organic frameworks with an unusual 3D inorganic subnetwork

Mixed zinc-lanthanide (Zn-Ln) metal-organic frameworks (MOFs) based on the 3,5-pyrazoledicarboxylate ligand exhibit an unusual three-dimensional (3D) inorganic subnetwork and display highly efficient photoluminescence.

The highly improved visible light photocatalytic activity of BiOI through fabricating a novel p–n heterojunction BiOI/WO3 nanocomposite

A novel BiOI/WO3 heterostructure was successfully synthesized using a facile ultrasonic process and used for the photocatalytic degradation of organic pollutants. The different BiOI loadings were investigated at the same time in this study. The heterostructure of BW-1.0 exhibited improved photocatalytic activity in comparison with pristine BiOI and WO3 with a 10.3- and 12.6-fold increase for Rhodamine B (RhB) degradation under visible light, respectively. The BiOI/WO3 heterostructured catalysts all exhibit the highest photocatalytic activity for degradation tetracycline (TC) under visible light. The excellent photocatalytic performance can be ascribed to the BiOI in close contact with WO3, which forms a heterojunction structure. This heterostructure composite photocatalyst results in an efficient charge separation at the interface, which is confirmed by photoelectron and photoluminescence spectroscopy. Moreover, trapping experiments indicated that h+ and ˙O2− were the main active species, with DMPO–˙O2− and DMPO–˙OH both being investigated. Moreover, the prepared sample shows good stability and recyclability, which are beneficial for its practical applications.

Fabrication and mechanism of a novel direct solid-state Z-scheme photocatalyst CdS/BiOI under visible light

A direct CdS/BiOI Z-scheme heterojunction has been successfully synthesized via a hydrothermal method for the first time. The photocatalytic performances of as-prepared samples were evaluated by rhodamine B degradation under visible light (λ > 420 nm) irradiation. The phase structures, morphologies and optical properties of the obtained samples were investigated by several characterization tools such as XRD, SEM, TEM, HRTEM, STEM, XPS, and UV-vis, photocurrent and PL spectroscopy. The results revealed that the CdS/BiOI Z-scheme heterojunction exhibited much higher photocatalytic activity than pure BiOI and CdS, and the sample of CdS/BiOI-2 showed the best activity among all the heterostructure photocatalysts. In addition, the ESR spectrum indicated that ˙O2− and e− were the main active species for the photocatalytic degradation of RhB in our experiment.

Synthesis, structure and characterization of two Cd(II) coordination polymers with helical structures

Two coordination polymers, [Cd2Cl2(1,3-BDC)(TTBT)(H2O)] (1) and [CdCl(1,4-HBDC)(TTBT)] (2) (1,3-BDC = 1,3-benzenedicarboxylate, 1,4-BDC = 1,4-benzenedicarboxylate, and TTBT = 10,11,12,13-tetrahydro-4,5,9,14-tetraaza-benzo[b]triphenylene), have been prepared under hydrothermal conditions and characterized by elemental analyses, IR spectra, thermal gravimetry (TG), fluorescence emission and single crystal X-ray diffraction analyses. The crystal structures were determined by X-ray diffraction and refined by full-matrix least-squares methods to R = 0.0621 and wR = 0.1543 using 4937 reflections with I > 2σ(I) for 1; and R = 0.0525 and wR = 0.1427 using 3386 reflections with I > 2σ(I) for 2. Compound 1 possesses a chiral chain structure. Adjacent chiral chains are further linked through π–π interactions between TTBT ligands to give a three-dimensional supramolecular architecture. Compound 2 displays a helical chain structure, with neighboring chains stacked by π–π interactions, generating an unusual three-dimensional supramolecular structure.

A simple and sensitive surface molecularly imprinted polymers based fluorescence sensor for detection of λ-Cyhalothrin.

In this study, surface molecularly imprinted YVO4:Eu(3+) nanoparticles with molecular recognitive optosensing activity were successfully prepared by precipitation polymerization using λ-Cyhalothrin (LC) as template molecules, methacrylic acid and ethylene glycol dimethacrylate as the polymerization precursors which could complex with template molecules, and the material has been characterized by SEM, TEM, FT-IR, XRD, TGA and so on. Meanwhile, the as-prepared core-shell structured nanocomposite (YVO4:Eu(3+)@MIPs), which was composed of lanthanide doped YVO4:Eu(3+) as fluorescent signal and surface molecular imprinted polymers as molecular selective recognition sites, could selectively and sensitively optosense the template molecules. After the experimental conditions were optimized, two linear relationship were obtained covering the concentration range of 2.0-10.0 μM and 10.0-90.0 μM, and the limit of detection (LOD) for LC was found to be 1.76 μM. Furthermore, a possible mechanism was put forward to explain the fluorescence quenching of YVO4:Eu(3+)@MIPs. More importantly, the obtained sensor was proven to be suitable for the detection of residues of LC in real examples. And the excellent performance of this sensor will facilitate future development of rapid and high-efficiency detection of LC.

Solvothermal synthesis and visible light-driven photocatalytic degradation for tetracycline of Fe-doped SrTiO3

In this paper, Fe-doped SrTiO3 (FSTO) photocatalysts were successfully prepared via a facile solvothermal method, and their photocatalytic activities for degrading tetracycline (TC) under visible light irradiation were examined. It was found that doping Fe3+ into the lattice of SrTiO3 resulted in the formation of new absorption bands in the visible light region, and the energy band gap decreased from 3.2 eV to 2.6 eV with Fe3+ doping amounts of 0 to 5 wt%. The photocatalytic experimental results indicated that the as-prepared FSTO photocatalysts generate an extremely high enhancement in the TC degradation ratio compared to the pure SrTiO3 under visible light irradiation. In particular, the FSTO sample doped with 3% Fe exhibited the highest TC degradation ratio (71.6%) in 80 min, which is mainly attributed to the narrowed gap generated by the appropriate level of Fe3+ doping. This work suggests that this doping method should be applicable for exploiting other efficient visible light-driven photocatalysts with wide band gap semiconductors.

Fabrication of a visible-light-driven photocatalyst and degradation of tetracycline based on the photoinduced interfacial charge transfer of SrTiO3/Fe2O3 nanowires

In our study, a new visible light-driven photocatalyst SrTiO3/Fe2O3 was first prepared via a simple two-step process using a hydrothermal process and electrospinning technique. The photocatalysts, composed of Fe2O3 nanowires (about 200 nm in diameter), were modified with SrTiO3 nanocube (about 50 nm) photocatalysts based on photoinduced interfacial charge transfer (IFCT). The as-prepared SrTiO3/Fe2O3 photocatalysts exhibit enhanced photocatalytic activity in degrading tetracycline (TC) over their corresponding single component under visible light irradiation. The efficient photocatalytic performance of the composites could be ascribed to the enhancement in visible light absorption efficiency and the efficient electron transfer from the valence band of the SrTiO3 nanoparticles to the Fe2O3 nanowires. This study shows their potential application in purifying TC pollution in environmental wastewater because of their high efficiency and stability.

Titanium dioxide macroporous materials doped with iron: synthesis and photo-catalytic properties

A series of iron doped three-dimensional (3D) ordered macroporous TiO2 hybrid materials (Fe–Ti–Oxide-M) have been successfully prepared by using polymethylmethacrylate nanospheres (PMMAs) as templates. The crystal structure of Fe–Ti–Oxide-M (50%) could be assigned to the Fe3Ti3O10 phase by XRD characterization. Synthetic samples were also studied by TEM and UV-vis absorption spectra in detail. All obtained samples possessed 3D ordered macroporous structures, and the absorption spectra of Fe–Ti–Oxide-M gradually extended to the visible light region with increased doping quantities of Fe. Furthermore, the photo-catalytic degradation of tetracycline (TC) was investigated, and the observed photo-catalytic performances of Fe–Ti–Oxide-M (1%, 2%, 5%, 10%, 20%, and 50%) were associated with their composition, which further indicates that the introduction of Fe has a remarkable influence on the photo-activity of 3D ordered macroporous TiO2 materials.