Changchun, Jilin | China
Main Specialties: Chemistry
Additional Specialties: Bioinspired Organized Matter
Yan Xu's current research interest is around bio-inspired organized matter. Based on bioinspired concepts, Xu's team seeks to advance a new integrative approach to the emergence of complex forms, the synthetic construction of organized matter and communications among nano-micro entities.
Yan Xu co-edited two books, one published by ELSEVIER in 2017 and one by World Scientific in 1995. She has more than 80 research articles, 3 patents (1 PCT, 2 Chinese) and 3 book chapters (Publisher: ACS, Wiley and China Science Press).
Primary Affiliation: Jilin University - Changchun, Jilin , China
RSC Adv. 2018 Aug;8(19):10361-10366.
Polymer nanocomposite fibers are important one-dimensional nanomaterials that hold promising potential in a broad range of technological applications. It is, however, challenging to organize advanced polymer nanocomposite fibers with sufficient mechanical properties and flexibility. Here, we demonstrate that strong, tough and flexible polymer nanocomposite fibers can be approached by electrospinning of a supramolecular ensemble of dissimilar and complementary components including flexible multiwalled carbon nanotubes (CNT), and stiff cellulose nanocrystals (CNC) in an aqueous poly(vinyl alcohol) (PVA) system. CNT and CNC are bridged by a water-soluble aggregation-induced-emission (AIE) molecule that forms - stacking with CNT via its conjugated chains, and electrostatic attraction with CNC through its positive charges leading to a soluble CNT-AIE-CNC ensemble, which further assembles with PVA through hydrogen bonds. A high level of ordering of the nanoscale building blocks combined with hydrogen bonding leads to a more efficient stress transfer path between the reinforcing unit and the polymer. The nanocomposite fiber mat is capable of selective detection of nitroaromatic explosives.
CrysEngComm. 2017 Oct 7; 19(37):5528-5531.
Fibre-in-tube TiO2-SnO2 fibres (FIT-TSF) have been successfully fabricated via a general crystalline-phase-induced formation strategy. The as-prepared FIT-TSF exhibited excellent sensing properties with an impedance change of three orders of magnitude, an ultrafast response time of 5 s, a recovery time of 8 s, and good reproducibility.
Adv Mater 2018 Mar 12;30(13):e1705948. Epub 2018 Feb 12.
State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University, 2699 Qianjin Street, Changchun, 130012, P. R. China.
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Dalton Trans. 2018 Feb 27
We report a novel one-dimensional zirconium-doped layered trititanate with porous core and textured surface of ultrafine nanofibers (∼5 nm) by hydrothermal alkaline treatment of electrospun fibers. It demonstrates superior efficiency for rapid, capacitive and simultaneous removal of multiple heavy metal ions such as Pb2+, Cd2+, Cu2+ and Zn2+. The adsorption is exceptionally rapid, showing 100% removal for Cu2+ in 10 min, and 100% removal for Pb2+ and Cd2+ in 20 min in water with a wide range of concentrations from 0.1 to 5 mmolL-1. It displays extraordinary adsorption capacity for highly toxic Pb2+ (2.91 mmolg-1). The sorption isotherms for Pb2+, Cd2+, Cu2+ and Sr2+ agree with the Langmuir model, indicating a monolayer adsorption. Corresponding sorption kinetics follow a pseudo-second-order model, suggesting a chemisorption-controlled adsorption process operating under the soft-hard Lewis acid-base principle. The crystal structure of the layered structure retains after the ion-exchange, endowing it promising potential for the remediation of heavy metal contaminated water.
Chemistry 2018 Feb 29;24(12):2980-2986. Epub 2018 Jan 29.
State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University, Changchun, 130012, P. R. China.
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Angew. Chem., Int. Ed. 2017 June 21, 56(30):8751-8755
Angewandte Chemie-International Edition
The structural transition in micrometer-sized liquid crystal bubbles (LCBs) derived from rod-like cellulose nanocrystals (CNCs) was studied. The CNC-based LCBs were suspended in nematic or chiral nematic liquid-crystalline CNCs, which generated topological defects and distinct birefringent textures around them. The ordering and structure of the LCBs shifted from a nematic to chiral nematic arrangement as water evaporation progressed. These packed LCBs exhibited a specific photonic cross-communication property that is due to a combination of Bragg reflection and bubble curvature and size.
Chem. Mater. 2017 May 9,29(9):3980-3988
Chemistry of Materials
Imparting aerogels with structural anisotropy endows these porous materials with direction-dependent properties and promising novel applicability in material science. However, facile fabrication of such anisotropic aerogels under mild conditions still remains a major challenge. Here, we report on the fabrication of anisotropic aerogels from liquid crystalline ordered cellulose nanocrystals (CNCs) by a directional freeze casting process. The resulting CNCs aerogels were millimeter sized with lamellar macrostructural features and optical anisotropy, exhibiting hierarchical structures perpendicular to the direction of freezing. We show that the birefringence of CNCs aerogels arose from the alignment of CNC liquid crystals, rather than from the shape of rod-like nanoparticles. Moreover, the versatility of the directional freezing approach was expanded to a CNC-silica system, resulting in anisotropic silica aerogels with an ordered mesopore-imprinted structure template by the liquid crystalline ordered CNCs. The highly directional alignment, optical anisotropy, hierarchical porosity, and large internal surface area of the CNC-based aerogels exhibit considerable potential for future fire-resistant, direction-dependent mechanical and electrical insulator applications.
CrysEngComm. 2017 May 21;19(19);2673-2680
Design and fabrication of hierarchically porous inorganic fibres holds exciting implications for applications in catalysis, separation, and energy devices. In this article, we present a general phase separation strategy for the fabrication of TiO2-SiO2 fibres with hierarchical pores via a typical electrospinning procedure. The porous hierarchy of the as-fabricated products and the possible formation mechanism have been investigated in detail. The results confirmed that the hydrophilic-hydrophobic repulsion between the PVP@ TBT@ TEOS 3D network complex and the solvent, the hydrolysis and polycondensation of inorganic alkoxides, and the slow solvent evaporation during the process of electrospinning may be responsible for the phase separation, leading to the formation of macropores in the fibres. The obtained hierarchically macro-/mesoporous TiO2-SiO2 fibres exhibited amazing structure stability even at a high calcination temperature of 850 degrees C. The current work may guide the further design of functional inorganic fibres with controllable hierarchical porous structures.
J. Phys. Chem. C. 2016 Nov 7;120(48):27541-27547.
JOURNAL OF PHYSICAL CHEMISTRY C
Controlling light matter interactions in optoplasmonic structures has recently attracted considerable attention due to their potential applications in metamaterials and metasurfaces. Here we present a bottom-up self-assembly method for large-scale organization of plasmonic silver nanorods (SNRs) into photonic liquid-crystalline cellulose nanocrystal matrices, exhibiting rationally engineered photonic plasmonic coupling across the near ultraviolet spectra range. In these metamaterials, we show that the resonant coupling of the photonic plasmonic mode has a strong effect not only on the stationary optical response of guest SNRs but also on controlling light in ultrashort time scales. By using the time-resolved femtosecond pump probe technique, we experimentally investigate the relaxation dynamics of SNRs embedded in hybrid photonic plasmonic systems as the photonic band gap of the host matrix provides a varying local density of optical states to manipulate the radiative lifetimes of SNRs. The close correlation between the structure and optical properties allows for rational design of optoplasmonic composites with tailored plasmonics and light processing, and it also paves the way for a well-defined field enhancement substrate with applications in ultrasensitive spectroscopies.
CrystEngComm. 2016 Oct 11;18(44):8637-8644.
The process of transforming solid electrospun fibers into coaxial hollow structures (wire-in-tubes) by controlled calcination has led to a variety of novel nano/microstructures with high aspect ratios and extended open channels. The governing mechanism of the calcination-induced structural evolution, however, remains controversial. Herein, we present our interpretation of the structural transformation from solid electrospun fibers into wire-in-tubes (single- and double-layer tubes) in a TiO2-VxOy system. We believe that the structural evolution is the result of a delamination of the crystalline crust from the underneath amorphous layer due to the different degrees of volume contraction, where the lock-up of the crystalline crust and the fluidity of the remaining organics plays vital roles. By tuning the calcination parameters, including the atmosphere, temperature and heating rate, the structural features of the hollow product fibers can be modulated.
Nanoscale. 2016 Aug;8(21):10928-10937.
Engineering hierarchical structures of electrode materials is a powerful strategy for optimizing the electrochemical performance of an anode material for lithium-ion batteries (LIBs). Herein, we report the fabrication of hierarchical TiO2/C nanocomposite monoliths by mediated mineralization and carbonization using bacterial cellulose (BC) as a scaffolding template as well as a carbon source. TiO2/C has a robust scaffolding architecture, a mesopore-macropore network and TiO2-C heterostructure. TiO2/C-500, obtained by calcination at 500 degrees C in nitrogen, contains an anatase TiO2-C heterostructure with a specific surface area of 66.5 m(2) g(-1). When evaluated as an anode material at 0.5 C, TiO2/C-500 exhibits a high and reversible lithium storage capacity of 188 mA h g(-1), an excellent initial capacity of 283 mA h g(-1), a long cycle life with a 94% coulombic efficiency preserved after 200 cycles, and a very low charge transfer resistance. The superior electrochemical performance of TiO2/C-500 is attributed to the synergistic effect of high electrical conductivity, anatase TiO2-C heterostructure, mesopore-macropore network and robust scaffolding architecture. The current material strategy affords a general approach for the design of complex inorganic nanocomposites with structural stability, and tunable and interconnected hierarchical porosity that may lead to the next generation of electrochemical supercapacitors with high energy efficiency and superior power density.
RSC Adv. 2016 Aug 1;6(80):76231-76236.
The ability to manipulate the color output of nanomaterials is important for applications like optoelectronic devices, light emitting display and lasers. Here, a self-organized helical superstructure of photonic cellulose loaded with upconversion nanoparticles of NaYF4:Yb, Er has been realized. The modulated upconversion luminescence of the photonic composite film of cellulose-NaYF4:Yb, Er has been demonstrated with the mechanism proposed.
Chem. Sci. 2016 Jul;7(2):1582-1587
Hierarchical zeolite monoliths with multimodal porosity are of paramount importance as they open up new horizons for advanced applications. So far, hierarchical zeolites based on nanotube scaffolds have never been reported. Inspired by the organization of biominerals, we have developed a novel precursor scaffolding-solid phase crystallization strategy for hierarchical zeolites with a unique nanotube scaffolding architecture and nanotube-trimodal network, where biomolecular self-assembly (BSA) provides a scaffolding blueprint. By vapor-treating Sil-1 seeded precursor scaffolds, zeolite MFI nanotube scaffolds are self-generated, during which evolution phenomena such as segmented voids and solid bridges are observed, in agreement with the Kirkendall effect in a solid-phase crystallization system. The nanotube walls are made of intergrown single crystals rendering good mechanical stability. The inner diameter of the nanotube is tunable between 30 and 90 nm by varying the thickness of the precursor layers. Macropores enclosed by cross-linked nanotubes can be modulated by the choice of BSA. Narrow mesopores are formed by intergrown nanocrystals. Hierarchical ZSM-5 monoliths with nanotube (90 nm), micropore (0.55 nm), mesopore (2 nm) and macropore (700 nm) exhibit superior catalytic performance in the methanol-to-hydrocarbon (MTH) conversion compared to conventional ZSM-5. BSA remains intact after crystallization, allowing a higher level of organization and functionalization of the zeolite nanotube scaffolds. The current work may afford a versatile strategy for hierarchical zeolite monoliths with nanotube scaffolding architectures and a nanotube-multimodal network leading to self-supporting and active zeolite catalysts, and for applications beyond.
CrystEngComm. 2016 Jun 6;18(29):5572-5579.
this article, we describe a general strategy, which combines electrospinning and hydrothermal processes, for the facile fabrication of one-dimensional hollow and solid porous titania (1DHP-TiO2 and 1DSP-TiO2). Amorphous TiO2 fibres were first fabricated by a conventional electrospinnning method and then used as precursors and templates for the subsequent hydrothermal reaction. Fluoride-mediated chemically induced self-transformation (CIST) was proposed to account for the formation of the hollow and solid porous structures. By controlling the parameters of the processes (i.e. porosity and diameter of the amorphous precursors, type of the mediated reactants), titania with tunable wall thickness and inner structures could be selectively fabricated. Besides, the obtained 1DHP-TiO2 and 1DSP-TiO2 exhibited good thermal stability. The organic residues and trace amounts of Na ions in 1DHP-TiO2 and 1DSP-TiO2 may act as stabilizers to raise the phase transformation temperature. Through this current general strategy based on CIST, it is expected that more functional 1D hollow and solid porous inorganic materials for advanced applications can be designed.
CrystEngComm. 2016 Jan 19;18(8):1321-1328.
The design of one-dimensional titania with tunable structural hierarchy holds exciting implications for applications such as optoelectronics, sensing and catalysis. Here, we report a general precursor strategy for one-dimensional titania with surface nanoprotrusion and tunable hierarchical structures realized via a titanate route using electrospun titania fibers as precursors. One-dimensional hierarchical hollow titanate (1D-HHT) was first fabricated under mild alkaline hydrothermal conditions from electrospun amorphous TiO2 precursors. The time-dependent evolution of 1D-HHT has been investigated in detail. The concerted effect of alkaline etching and Ostwald ripening is responsible for the surface nanoprotrusion and modulation of structural hierarchy. Anatase TiO2 with the same hierarchical structures can be obtained using controlled calcination. The as-fabricated one-dimensional titania with varying levels of structural hierarchy exhibits about 1.3-1.5 times higher power conversion efficiency than commercial P25 as a photoanode material for dye-sensitized solar cells (DSSCs). The current work may be extended for more functional TiO2-based materials with tunable structural hierarchy and could widen the application range of electrospinning technology for one-dimensional hierarchical structures.
J. Mater. Chem. C. 2016 Jan 21;4(9):1764-1768.
Journal of Materials Chemistry C
Chiral fluorescent composite films of gold nanoclusters (AuNCs) and photonic cellulose nanocrystals (CNCs) demonstrate modulated fluorescence emission due to the stopband- and band edge-photoemission coupling effect between the photonic CNCs and fluorescent AuNCs, showing promising potentials as fluorescent nanosensors, optical switches and optical memory devices.
ACS Appl. Mater. Interf. 2015 Oct 7;7(39):21797-20806.
ACS APPLIED MATERIALS & INTERFACES
Photonic crystals incorporating with plasmonic nanopartides have recently attracted considerable attention due to their novel optical properties and potential applications in future subwavelength optics, biosensing and data storage device. Here we demonstrate a free-standing chiral plasmonic film composed of entropy-driven self-co-assembly of gold nanoparticles (GNPs) and rod-like cellulose nanocrystals (CNCs). The CNCs-GNPs composite films not only preserve the photonic ordering of the CNCs matrix but also retain the plasmonic resonance of GNPs, leading to a distinct plasmon-induced chiroptical activity and a strong resonant plasmonic photonic coupling that is confirmed by the stationary and ultrafast transient optical response. Switchable optical activity can be obtained by either varying the incidence angle of lights, or by taking advantage of the responsive feature of the CNCs matrix. Notably, an angle-dependent plasmon resonance in chiral nematic hybrid film has been observed for the first time, which differs drastically from that of the GNPs embed in three-dimensional photonic crystals, revealing a close relation with the structure of the host matrix. The current approach for fabricating device-scale, macroscopic chiral plasmonic materials from abundant CNCs with robust chiral nematic matrix may enable the mass production of functional optical metamaterials.
J. Phys. Chem. C. 2015 Jul 1;119(31):17552-17560.
Journal of Physical Chemistry C
Hierarchical structuration has proven to be effective in optimizing the functional performance of nanomaterials. Herein, we report for the first time the evolution of a titania tube-in-tube scaffolding architecture with multilength-scale structural hierarchy (TITS TiO2) and structure-enhanced functional performance. The nanoengineering was accomplished by a precursor scaffolding-concurrent epitaxial growth approach using bacterial cellulose (BC) as a bioscaffold. The BC@SiO2@TiO2 precursor scaffold with a sandwiching SiO2 layer plays an essential role in the formation of the tube-in-tube geometry. TITS TiO2 exhibits significantly superior photocatalytic activity to Degussa P25. It shows great UV light absorption ability and high specific surface area, which we believe are responsible for its superior photocatalytic activity. The monolithic nature of TITS TiO2 makes photocatalyst separation and recovery possible. We show that TiO2 nanocrystals can be used as a building block for the organization of complex inorganic nanomaterials with multilength-scale structural hierarchy using a bioscaffold with desired structural features: monolith (millimeter and above), macropore (micrometer), and nanotube/nanopore (nanometer), offering a versatile route for the design of advanced hierarchical nanomaterials.
ACS Appl. Mater. Interf. 2015 Jun 10;7(22):11863-11870.
ACS APPLIED MATERIALS & INTERFACES
Plasmonic materials with large chiroptical activity at visible wavelength have attracted considerable attention due to their potential applications in metamaterials. Here we demonstrate a novel guest-host chiral nematic liquid crystal film composed of bulk self-co-assembly of the dispersed plasmonic silver nanowires (AgNWs) and cellulose nanocrystals (CNCs). The AgNWs-CNCs composite films show strong plasmonic optical activities, that are dependent on the chiral photonic properties of the CNCs host medium and orientation of the guest AgNWs. Tunable chiral distribution of the aligned anisotropic AgNWs with long-range order is obtained through the CNCs liquid crystal mediated realignment. The chiral plasmonic optical activity of the AgNWs-CNCs composite films can be tuned by changing the interparticle electrostatic repulsion between the CNCs nanorods and AgNWs. We also observe an electromagnetic energy transfer phenomena among the plasmonic bands of AgNWs, due to the modulation of the photonic band gap of the CNCs host matrix. This facile approach for fabricating chiral macrostructured plasmonic materials with optically tunable property is of interest for a variety of advanced optics applications.
J. Mater. Chem. C. 2015 Feb 17;3(14):3384-3390.
Journal of Materials Chemistry C
A novel chiral nematic luminescent film is fabricated by incorporating YVO4:Eu3+ nanoparticles with cellulose nanocrystals. We have shown that these nanoparticles could attach to the surface of twisted nanorods of cellulose, exhibiting electronic transition-based hierarchical chiroptical activity, responsible for strong circularly polarized emission and a high luminescence polarization dissymmetry factor.
ChemSusChem. 2014;8(1):1-29 (Back cover).
Transforming plant biomass to biofuel is one of the few solutions that can truly sustain mankind's long-term needs for liquid transportation fuel with minimized environmental impact. However, despite decades of effort, commercial development of biomass-to-biofuel conversion processes is still not an economically viable proposition. Identifying value-added co-products along with the production of biofuel provides a key solution to overcoming this economic barrier. Lignin is the second most abundant component next to cellulose in almost all plant biomass; the emerging biomass refinery industry will inevitably generate an enormous amount of lignin. Development of selective biorefinery lignin-to-bioproducts conversion processes will play a pivotal role in significantly improving the economic feasibility and sustainability of biofuel production from renewable biomass. The urgency and importance of this endeavor has been increasingly recognized in the last few years. This paper reviews state-of-the-art oxidative lignin depolymerization chemistries employed in the papermaking process and oxidative catalysts that can be applied to biorefinery lignin to produce platform chemicals including phenolic compounds, dicarboxylic acids, and quinones in high selectivity and yield. The potential synergies of integrating new catalysts with commercial delignification chemistries are discussed. We hope the information will build on the existing body of knowledge to provide new insights towards developing practical and commercially viable lignin conversion technologies, enabling sustainable biofuel production from lignocellulosic biomass to be competitive with fossil fuel.
RSC Adv. 2015;5(3):1673-1679.
Hierarchically nanostructured TiO2 has been hydrothermally synthesized using cellulose as a biotemplate involving various types of acids. We show that the surface charges of nanocrystalline cellulose and reaction parameters including reaction temperature, acid to cellulose ratio and reaction time have a large effect on the morphology and nanostructures of TiO2 products. The photocatalytic activity of as-synthesized, calcined hierarchically nanostructured TiO2 and calcined hierarchically nanostructured TiO2 loaded Au nanoparticles is evaluated by photo-degradation of methyl orange under white light.
J. Mater. Chem. A. 2015;3(4):1709-1716.
Journal of Materials Chemistry A
Visible-light photocatalytic H-2 production by water splitting is of great importance for its promising potential in converting solar energy to chemical energy. Zn(x)Cd1-S-x-based systems are intrinsic visible-light photocatalysts with appropriate electronic band structure and negative reduction potential of photoexcited electrons; however, the H-2 evolution rate is far from satisfactory. A common strategy for improving the photocatalytic activity includes the incorporation of expensive cocatalysts such as noble metals and graphene. Here, we report, for the first time, that high visible-light photocatalytic H-2 production activity can be achieved by organizing Zn(x)Cd1-S-x nanoparticles into the hierarchical architecture of bacterial cellulose (BC). This is achieved by templated mineralization and ion exchange/seeded growth. The bionanocomposite foams of Zn(x)Cd1-S-x/BC are flexible, monolithic and hierarchically porous. The optimized Zn0.09Cd0.91S/BC exhibits a high H-2 evolution rate of 1450 mu mol h(-1) g(-1) and an excellent apparent quantum efficiency of 12% at 420 nm. The monolithic nature of Zn(x)Cd1-S-x/BC makes catalyst recovery and recycling possible. The current work manifests that the integration of intrinsic chemical properties with multilength scale structural hierarchy affords performance optimization.
J. Mater. Chem. C. 2014 Nov 21;2(43):9189-9195.
Journal of Materials Chemistry C
Chiral nematic mesoporous yttrium oxide films are attractive for the design of new optical devices. The free-standing chiral nematic mesoporous films of Y2O3:Eu3+ are assembled using a hard-templating method using nanocrystalline cellulose-templated silica. The Y2O3:Eu3+ films with tunable optical properties are capable of modulating the spontaneous emission of Eu3+ ions and exhibit interesting photoluminescence properties.
J. Mater. Chem. A. 2014 May 15;2(31):12442-12448.
Journal of Materials Chemistry A
Design of heterostructured TiO2-SiO2 fibers with desired porous hierarchy holds exciting implications for applications such as optoelectronics, adsorption, sensing and catalysis. The current work demonstrates for the first time that the porous hierarchy of TiO2-SiO2 fibers can be regulated based on the hydrolysis and polycondensation of inorganic alkoxides. The fabrication of porous TiO2-SiO2 fibers is accomplished by single-spinneret electrospinning without using sacrificial templates and special heat treatment. The TiO2-SiO2 composite fibers with narrow mesopores, meso-macropores and micro-meso-macropores have been obtained, and the factors governing the porous hierarchy have been investigated. The presence of Ti-O-Si linkages and the interfaces between amorphous and crystalline domains are evidenced by XPS and high magnification TEM. Mesoporous TiO2-SiO2 fibers exhibit excellent photocatalytic activity in the degradation of Rhodamine B comparable to Degussa P25. The photocatalytic activities of the TiO2-SiO2 fibers may be attributed to the combined merits of mesoporosity, high specific surface area, good adsorption capacity for Rhodamine B and anatase-rutile heterojunction. The current contribution unveils the potential of the hydrolysis and polycondensation chemistry of inorganic alkoxides in the design of heterostructured inorganic fibers with desired porous hierarchy for advanced applications.
RSC Adv. 2014 May 2;4(42):21815-21818.
Zinc oxide aerogel-like materials with interconnected multimodal porosity and an intriguing interwoven hollow-sphere morphology were generated from zinc oxide/bacterial cellulose nanocomposite foams by controlled calcination. The monolithic zinc oxide aerogel- like materials with hierarchical porosity and high specific surface area exhibit excellent selective ethanol sensing properties.
J. Phys. Chem. C. 2014 May 20;118(11):5782-5788.
Journal of Physical Chemistry C
Helical core-satellite nanoarchitectures of AgNR@Cys@AuNPs have been successfully fabricated by self-assembly of Ag nanorods and Au nanoparticles, using L- and D-cysteine as bridging molecules, respectively. The chirality of the nanoarchitectures is confirmed by circular dichroism spectroscopy, and the results suggest that the chirality of nanoarchitectures relicates the L- and D-conformation of cysteine. The absorption peak of AgNR@Cys@AuNPs nanoarchitectures on the circular dichroism spectra shows a gradual red-shift with increasing cysteine concentration. The helical arrangement of Au nanoparticles in the nanoarchitectures is strongly dependent on the shape of Ag backbones and the cysteine concentration.
Dalton Trans. 2014 May 20;43(41):15321-15327 (Front cover).
Integration of luminescent rare earth ions and iridescence into a zirconium oxide photonic material is attractive for the design of new optical devices. The free-standing chiral nematic mesoporous films of ZrO2:Eu3+ are assembled by a hard-templating approach using nanocrystalline cellulose-templated silica. The ZrO2:Eu3+ films show tunable optical properties. The chiral nematic structured ZrO2:Eu3+ exhibits selective suppression of the spontaneous emission of Eu3+ and the capability to modulate the lifetime of luminescent Eu3+.
Dalton Trans. 2014 Feb 7;43(18):6762-6768.
The use of self-assembled biomacromolecules in the development of functional bionanocomposite foams is one of the best lessons learned from nature. Here, we show that monolithic, flexible and porous zinc oxide bionanocomposite foams with a hierarchical architecture can be assembled through the mediation of bacterial cellulose. The assembly is achieved by controlled hydrolysis and solvothermal crystallization using a bacterial cellulose aerogel as a template in a non-aqueous polar medium. The bionanocomposite foam with a maximum zinc oxide loading of 70 wt% is constructed of intimately packed spheres of aggregated zinc oxide nanocrystals exhibiting a BET surface area of 92 m(2) g(-1). The zinc oxide bionanocomposite foams show excellent antibacterial activity, which give them potential value as self-supporting wound dressing and water sterilization materials.