Fangzhi Huang

Self‐Assembled 3D Flowerlike Hierarchical Fe3O4@Bi2O3 Core–Shell Architectures and Their Enhanced Photocatalytic Activity under Visible Light

Three-dimensional (3D) flowerlike hierarchical Fe(3)O(4)@Bi(2)O(3) core-shell architectures were synthesized by a simple and direct solvothermal route without any linker shell. The results indicated that the size of the 3D flowerlike hierarchical microspheres was about 420 nm and the shell was composed of several nanosheets with a thickness of 4-10 nm and a width of 100-140 nm. The saturation magnetization of the superparamagnetic composite microspheres was about 41 emu g(-1) at room temperature. Moreover, the Fe(3)O(4)@Bi(2)O(3) composite microspheres showed much higher (7-10 times) photocatalytic activity than commercial Bi(2)O(3) particles under visible-light irradiation. The possible formation mechanism was proposed for Ostwald ripening and the self-assembled process. This novel composite material may have potential applications in water treatment, degradation of dye pollutants, and environmental cleaning, for example.

Magnetic Fe3O4@C@Cu2O composites with bean-like core/shell nanostructures: Synthesis, properties and application in recyclable photocatalytic degradation of dye pollutants

Magnetic Fe3O4@C@Cu2O composites with a bean-like core/shell nanostructure have been successfully synthesized by a self-assembly approach. The synthetic route is feasible, low-cost and green. The size of the as-prepared magnetic composites is about 420 nm and the shells are composed of several nanoparticles in the range of 5∼10 nm. Interestingly, the carbonaceous layer with bound hydrophilic groups inherited from the starting materials acted as both the linker and the stabilizer between Fe3O4 and Cu2O. The Fe3O4@C@Cu2O composites exhibit ferromagnetic behaviour, and good dispersibility in aqueous solution. Importantly, the bean-like core/shell composites show universal and powerful visible-light-photocatalytic activity for the degradation of Rhodamine-B (RhB), methyl orange (MO), and alizarin red (AR) relative to commercial Cu2O and Degussa P-25 powders. These novel magnetic composites may find applications in dye water treatment, degradation of organic pollutants and environmental cleaning etc.

In Situ Growth of Matchlike ZnO/Au Plasmonic Heterostructure for Enhanced Photoelectrochemical Water Splitting

In this paper, we report a novel matchlike zinc oxide (ZnO)/gold (Au) heterostructure with plasmonic-enhanced photoelectrochemical (PEC) activity for solar hydrogen production. The matchlike heterostructure with Au nanoparticles coated on the tip of ZnO nanorods is in situ grown on a zinc (Zn) substrate by using a facile hydrothermal and photoreduction combined approach. This unique heterostructure exhibits plasmonic-enhanced light absorption, efficient charge separation and transportation properties with tunable Au contents. The photocurrent density of the matchlike ZnO/Au heterostructure reaches 9.11 mA/cm(2) at an applied potential of 1.0 V (vs Ag/AgCl) with an Au/Zn atomic ratio of 0.039, which is much higher than that of the pristine ZnO nanorod array (0.33 mA/cm(2)). Moreover, the solar-to-hydrogen conversion efficiency of this special heterostructure can reach 0.48%, 16 times higher than that of the pristine ZnO nanorod array (0.03%). What is more, the efficiency could be further improved by optimizing the Au content of the heterostructure. The formation mechanism of such a unique heterostructure is proposed to explain the plasmonic-enhanced PEC performance. This study might contribute to the rational design of the visible-light-responsive plasmonic semiconductor/metal heterostructure photoanode to harvest the solar spectrum.

Self-healable hydrogel on tumor cell as drug delivery system for localized and effective therapy

A self-healable chitosan(CS)/polyvinyl alcohol (PVA) hydrogel as an injectable drug carrier was first prepared in situ on tumor cells for effective and localized therapy. PVA molecules have a synergistic effect on the formation and maintenance of 3D network conformation of hydrogel. The hydrogel shows good biocompatibility and could be easily and rapidly formed. When loaded with fluorouracil (5-FU), the hydrogel possessed good drug retention ability at pH 7.4, which can prevent the loss of drug to normal cells and reduce the side effect. As well, the hydrogel shows continuous and controllable drug release, with the final cumulative releasing amount of 84.8% at pH 5.0. Therefore, the hydrogel not only could maintain a higher 5-FU concentration around tumor cells to enhance the antitumor effect, but also can achieve pH sensitive controllable drug release at the lesion site. Meantime, the attractive self-healing ability of the CS/PVA hydrogel is first revealed in this study, which contributes to the regeneration of its integral network from the broken fragments. The CS/PVA hydrogel may hold promise for better applications in anti-tumor therapy.

Novel TiO2/PEGDA Hybrid Hydrogel Prepared in Situ on Tumor Cells for Effective Photodynamic Therapy

A novel inorganic/organic hybrid hydrogel system containing titanium dioxide (TiO2)/poly(ethylene glycol) double acrylates (PEGDA) was prepared by in situ photopolymerization on tumor cells for photodynamic therapy (PDT). TiO2 nanorods with diameter of ∼5 nm and length of ∼25 nm in this system presented dual functions, as effective photosensitizers for PDT and initiators for causing the in situ formation of hydrogel, under near-infrared (NIR) irradiation. The hybrid hydrogel retained the TiO2 around tumor cell to form a drug-loaded hydrogel shell. This resulted in a high concentration of singlet oxygen ((1)O2) under NIR irradiation, which induced apoptosis of tumor cell. Also, the hydrogel could reduce the side effects by preventing TiO2 from migrating to normal tissue. Furthermore, the TiO2 nanorods in this hydrogel shell were photochemically recyclable and could be reused in regular treatment. The outcomes of this study provide a new way to exploit multifunction of inorganic semiconductor nanomaterials for a variety of biomedical applications.

Controlled synthesis, growth mechanism and optical properties of FeWO4 hierarchical microstructures

Monoclinic ferrous tungstate (FeWO4) microcrystals with hierarchical nano/microstructures have been selectively synthesized via a facile hydrothermal process in the presence of ethylenediamine tetraacetic acid disodium salt (Na2EDTA) and hexamethylenetetramine (HMT). HMT played triple roles as the reducing agent, alkaline source, and crystal growth modifier, while Na2EDTA served as the chelating reagent and structure-directing agent. The appropriate conditions for synthesis of multilayer flower-like FeWO4 were 200 °C and 8 h with the concentrations of Na2EDTA and HMT at 0.03 mol L−1 and 0.025 mol L−1, respectively. The morphology of FeWO4 showed dramatic changes from a bulky amorphous crystal to multilayer hexangular microcrystals with increasing Na2EDTA concentration, while increasing HMT concentration would transform the hexagonal structure to a sixfold symmetry architecture and the aspect ratio of symmetry axis decreased gradually. Ostwald ripening and the self-assembled process was proposed for the possible formation mechanism. The photoluminescence (PL) intensity of the multilayer FeWO4 microcrystals was higher than that of other FeWO4 structures. Magnetic measurement of hexangular FeWO4 microcrystals showed a small ferromagnetic ordering at low temperature. Furthermore, this work may open novel routes to the chelating reagent-assisted synthesis of hierarchical architectures with various morphologies.

Reduced Graphene Oxide/Amaranth Extract/AuNPs Composite Hydrogel on Tumor Cells as Integrated Platform for Localized and Multiple Synergistic Therapy

Integration of multimodal treatment strategies combined with localized therapy to enhance antitumor efficacy and reduce side effects is still a challenge. Herein, a novel composite hydrogel containing rGO, amaranth extract (AE) and gold nanoparticles (AuNPs) was prepared by using AE as both reductant and cross-linking agent. The chlorophyll derivatives in AE were also employed as a photodynamic therapy drug. Meanwhile, AuNPs and rGO both have obvious photothermal effects and can accelerate the generation of cytotoxic singlet oxygen (1O2). The temperature increase of rGO/AE/AuNPs precursor is up to 6.3 °C under 808 nm laser irradiation at a power density of 200 mW·cm(-2). The hydrogel shell on in situ tumor cells was easily formed and regulated by near-infrared irradiation within 10 min, which could both retain a high concentration of drugs on the lesion site and prevent them from migrating to normal tissue, thus reducing the side effects. Compared with rGO/AE and AE, rGO/AE/AuNPs showed a remarkably improved and synergistic antitumor effect. The hydrogel possesses good biocompatibility and high hydrophilicity and could be used for loading chemotherapeutics, which provides a new approach for located and multiple antitumor therapies.

Functionalization of cotton fabrics with rutile TiO2 nanoparticles: Applications for superhydrophobic, UV-shielding and self-cleaning properties

The superhydrophobic cotton fabrics were prepared by combining the coating of titanium dioxide (TiO2) with the subsequent dodecafluoroheptyl-propyl-trimethoxysilane (DFTMS) modification. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) measurements revealed that the nanosized TiO2 sphere consisted of granular rutile. The TiO2 layer coated on the cotton altered both the surface roughness for enhancing the hydrophobicity and UV-shielding property. The cotton fabric samples showed excellent water repellency with a water contact angle as high as 162°. The UV-shielding was characterized by UV-vis spectrophotometry, and the results indicated that the fabrics could dramatically reduce the UV radiation. The photocatalytic progress showed that organic stains were successfully degraded by exposure of the stained fabric to UV radiation. Such multifunctional cotton fabrics may have potentials for commercial applications.

Hierarchical Cu(OH)2@Ni2(OH)2CO3 core/shell nanowire arrays in situ grown on three-dimensional copper foam for high-performance solid-state supercapacitors

Well-aligned hierarchical Cu(OH)2@Ni2(OH)2CO3 core/shell nanowire arrays were prepared on conductive copper foam via a simple in situ oxidation reaction and subsequent hydrothermal method for high-performance solid-state supercapacitors. Such novel hierarchical architectures integrate the merits of macroporous copper foam and the core/shell nanowire arrays such as superior electrical conductivity, enlarged surface area, and fast charge transport and ion diffusion. The areal capacitance of this typical hierarchical Cu(OH)2@Ni2(OH)2CO3 core/shell nanowire array reaches 1.09 F cm−2 at a current density of 1.0 mA cm−2, much higher than that of pristine Cu(OH)2 nanowire arrays (0.36 F cm−2). In addition, a remarkable rate capability (0.91 F cm−2 at a current density of 25 mA cm−2) and excellent cycling stability (86.1% after 10 000 cycles) were observed. Moreover, the hierarchical Cu(OH)2@Ni2(OH)2CO3 core/shell nanowire arrays were also used as the positive electrodes to fabricate solid-state asymmetric supercapacitor devices, exhibiting a high cell voltage of 1.6 V and largely enhanced energy density up to 1.01 W h cm−2. The improvement in electrochemical behaviors is attributed to the unique hierarchical architecture and the component synergistic effect. This work provides a scalable and promising strategy for the synthesis of well-defined core/shell nanoarrays as energy storage and conversion devices.

Preparation and multiple antitumor properties of AuNRs/spinach extract/PEGDA composite hydrogel.

In this study, a novel composite hydrogel that contains spinach extract (SE), gold nanorods (AuNRs), and poly(ethylene glycol) double acrylates (PEGDA) is prepared through a one-step in situ photopolymerization under noninvasive 660 nm laser irradiation for localized antitumor activity. SE plays a role as a photoinitiator for initiating the formation of the PEGDA hydrogel and as an excellent photosensitizer for generating cytotoxic singlet oxygen ((1)O2) with oxygen to kill tumor cells. AuNRs can be used as a photoabsorbing agent to generate heat from optical energy. Moreover, the introduction of AuNRs is conducive to the formation of the hydrogel and accelerates the rate of (1)O2 generation. The composite hydrogel shell, which has good biocompatibility on tumor cells, can prevent the photosensitizer from migrating to normal tissue and maintains a high concentration on lesions, thereby enhancing the curative effect. The combination of NIR light-triggered mild photothermal heating of AuNRs, the photodynamic treatment using SE, and localized gelation by photopolymerization exhibits a synergistic effect for the destruction of cancer cells.