Search

A versatile synthetic method, which is based on a low-temperature hydrothermal technique, is developed for the fabrication of a microporous ZnO/TiO2 composite catalyst with different structures (e.g., amorphous, amorphous/crystalline and crystalline). In particular, a novel microporous ZnO/TiO2 composite with amorphous/crystalline structure is obtained with a 3/1 M ratio of Ti/Zn. This novel ZnO/TiO2 composite heterostructure not only has a large specific surface area (311.9 m2 g−1) but also exhibits outstanding performance during solar water splitting reactions to generate hydrogen without a noble metal co-catalyst. Based on our in-depth mechanistic analysis, the synergistic effect between the amorphous ZnO and crystalline TiO2 is responsible for the enhanced performance of this material.

We present an electrochemical route to synthesize silver nanoplates on seed-decorated Indium tin oxide (ITO) glass substrate. The nanoplates are several tens of to several hundred nanometers in dimension. The density of nanoplates covered on the substrate can be controlled well by adjusting the amounts of seed. All the nanoplates are standing on the substrate uniformly even at very high density. Silver nanoplate arrays displayed an extraordinary superhydrophobicity after chemical modification and can serve as highly active surface-enhanced Raman scattering (SERS) substrates for microdetection. The arrays can also be used as electrodes for electrochemical capacitor with high power density.

A bottom-up based photomediated strategy is presented to create single crystalline silver spherical particles by pulsed laser irradiation of silver nanoparticles in liquid, where the unique selective laser heating is responsible for the formation of spherical particles. The present approach is facile and flexible for the design of silver spherical particles with tunable sizes. Systematical studies reveal that the experimental parameters including laser fluence, laser irradiation time, dispersing liquid, and concentration of starting material are important factors that influence the formation of silver spherical particles. As a demonstration of the as-synthesized silver spheres for electrochemical applications, the performance of silver spherical particles as potential supercapacitors was investigated by cyclic voltammetry, and the results indicated a higher capacity of silver spherical particles compared to that of silver raw nanoparticles, which is considered to originate from the enhanced electronic conductivity due to the single crystalline feature of silver spherical particles. We believe that the photomediated method presented in this work can be set as a new alternative in creating a variety of noble metallic spherical particles.

Ni0.9Fe0.1 alloy-supported solid oxide fuel cells with NiTiO3 (NTO) infiltrated into the cell support from 0 to 4 wt.% are prepared and investigated for CH4 steam reforming activity and electrochemical performance. The infiltrated NiTiO3 is reduced to TiO2-supported Ni particles in H2 at 650 °C. The reforming activity of the Ni0.9Fe0.1-support is increased by the presence of the TiO2-supported Ni particles; 3 wt.% is the optimal value of the added NTO, corresponding to the highest reforming activity, resistance to carbon deposition and electrochemical performance of the cell. Fueled wet CH4 at 100 mL min−1, the cell with 3 wt.% of NTO demonstrates a peak power density of 1.20 W cm−2 and a high limiting current density of 2.83 A cm−2 at 650 °C. It performs steadily for 96 h at 0.4 A cm−2 without the presence of deposited carbon in the Ni0.9Fe0.1-support and functional anode. Five polarization processes are identified by deconvoluting and data-fitting the electrochemical impedance spectra of the cells under the testing conditions; and the addition of TiO2-supported Ni particles into the Ni0.9Fe0.1-support reduces the polarization resistance of the processes ascribed to CH4 steam reforming and gas diffusion in the Ni0.9Fe0.1-support and functional anode.

Ni0.9Fe0.1 alloy-supported solid oxide fuel cells with NiTiO3 (NTO) infiltrated into the cell support from 0 to 4 wt.% are prepared and investigated for CH4 steam reforming activity and electrochemical performance. The infiltrated NiTiO3 is reduced to TiO2-supported Ni particles in H2 at 650 °C. The reforming activity of the Ni0.9Fe0.1-support is increased by the presence of the TiO2-supported Ni particles; 3 wt.% is the optimal value of the added NTO, corresponding to the highest reforming activity, resistance to carbon deposition and electrochemical performance of the cell. Fueled wet CH4 at 100 mL min−1, the cell with 3 wt.% of NTO demonstrates a peak power density of 1.20 W cm−2 and a high limiting current density of 2.83 A cm−2 at 650 °C. It performs steadily for 96 h at 0.4 A cm−2 without the presence of deposited carbon in the Ni0.9Fe0.1-support and functional anode. Five polarization processes are identified by deconvoluting and data-fitting the electrochemical impedance spectra of the cells under the testing conditions; and the addition of TiO2-supported Ni particles into the Ni0.9Fe0.1-support reduces the polarization resistance of the processes ascribed to CH4 steam reforming and gas diffusion in the Ni0.9Fe0.1-support and functional anode.

Visible–light active (N, P)-codoped TiO2 (NP-TiO2) nanoparticles are prepared by one step hydrothermal method and characterized by XPS, XRD, SEM, FT-IR and UV–vis spectrum. Based on the XPS analysis, the chemical state of N in TiO2 is identified as N–Ti–O in the anatase TiO2 lattice, while P exists in a pentavalent-oxidation state (P5+) or as PO 4 3 - group coordinating in TiO2. The result confirms that the doping of phosphate would affect the crystallite size and structure of anatase. UV–vis spectra demonstrates that NP-TiO2 could shift the absorption edge of titania to the visible–light region effectively, which could increase the visible–light photocatalytic activity. The total degradation of methylene blue (MB) and rhodamine B (RhB) is significantly faster on NP-TiO2 samples than that on N-doped and NS-codoped TiO2 under visible–light irradiation.

Flexible structural design and accurate controlled fabrication with structural tunability according to need for binary or multicomponent colloidal crystals have been expected. However, it is still a challenge. In this work, the phase diagram of monolayer binary colloidal crystals (bCCs) is established on the assumption that both large and small polystyrene (PS) colloidal spheres can stay at the air/water interface, and the range diagram for the size ratio and number ratio of small to large colloidal spheres is presented. From this phase diagram, combining the range diagram, we can design and relatively accurately control fabrication of the bCCs with specific structures (or patterns) according to need, including single or mixed patterns with the given relative content. Further, a simple and facile approach is presented to fabricate large-area (more than 10 cm(2)) monolayer bCCs without any surfactants, using differently sized PS spheres, based on ethanol-assisted self-assembly at the air/water interface. bCCs with different patterns and stoichiometries are thus designed from the established phase diagram and then successfully fabricated based on the volume ratios (V(S/L)) of the small to large PS suspensions using the presented colloidal self-assembling method. Interestingly, these monolayer bCCs can be transferred to any desired substrates using water as the medium. This study allows us to design desired patterns of monolayer bCCs and to more accurately control their structures with the used V(S/L).

Mesoporous (N, S)-codoped TiO2 was simply prepared by a solvothermal method with thiourea as N and S source. The as-prepared products were characterized by XRD, SEM, XPS, BET and UV–vis. The results confirm that N and S have been incorporated into the lattice of anatase TiO2, which brings an obvious red-shift of the absorption edge into visible-light region. Moreover, the codoped products exhibit high photocatalytic activity under the visible-light irradiation.

(N, S)-codoped titania (TiO2) is synthesized by a simple template-free solvothermal method as photoanode for dye-sensitized solar cells (DSSCs). The results confirm that N and S have been doped into the lattice of anatase, which can enhance the visible-light absorbance and promote the electron transportation in TiO2. The prepared (N, S)-codoped TiO2 exhibits pure anatase phase mesoporous nanoparticles with average diameter of 60 nm. Mixing (N, S)-codoped TiO2 with Degussa P25 as photoanode results in the improvement of open-circuit voltage and short-circuit photocurrent density of DSSC. And the corresponding DSSC obtains a high conversion efficiency of 8.0%.

Electronic and optical properties of pure, N-doped, Fe-doped and (N, Fe)-codoped anatase TiO2 were evaluated, respectively, by using the density functional theory. The results indicate that the elemental doping narrows the band gap of TiO2 and realize its visible-light response activity; and incorporation of Fe into N-doped TiO2 further increases the photocatalytic activity under visible-light irradiation compared with that of the N-doped TiO2.

Fabrication of size-tailored semiconductor/metal submicrometer spherical particles has recently attracted signifi cant interest due to their unique physicochemical properties and emerging applications in many strategically important fi elds such as photonic crystals, pharmaceuticals, electronics, catalysis, energy, and environmental protection. [ 1 ] ZnO, with a wide bandgap of 3.37 eV and a large exciton binding energy of 60 meV, is one of the key semiconductors, widely utilized in piezoelectric transducers, varistors, phosphors, sensors, solar cells, and transparent conducting fi lms. [ 2 ] Due to the intrinsic nature of polar hexagonal-phase ZnO with an a : c axial ratio of 1:1.6, diverse well-defi ned 1D nanostructures have been synthesized [ 3 ] and utilized in a variety of functional device applications, such as light-emitting diodes, nanolasers, photodetectors, fi eld-effect transistors, photovoltaic devices, nanogenerators, and chemical sensors. [ 4 ] Comparatively, the creation of spherical crystals of ZnO, which are thought to be an attractive material for photonic crystals, sensors, solar cells, and photocatalysts, has seldom been reported. [ 5 ] Furthermore, even within those few existing reports, the resultant submicrometer ZnO spherical particles have usually been built up by secondary structures, such as nanoparticles and nanoplates, [ 5 ] where the lack of close contact between nanostructures will inevitably infl uence and possibly reduce the performance of ZnO submicrometer spheres in electric, magnetic, optoelectric, and thermoelectric applications. Consequently, it remains a challenge to acquire ZnO submicrometer spheres constructed without subunits. However, the synthesis of such spherical semiconductor/metal particles has been rarely reported. One effective approach has

A simple and flexiable route is presented to fabricate ordered micro/nanostructured porous films, based on a monolayer colloidal crystal template and solution dipping. In 2 O 3 is chosen as a main model material to demonstrate the validity of the given fabrication strategy. It has been shown that the porous films with different microstructures, can be constructed directly on any desired substrate (with flat, curved, or even rough surface). The separately tunable sensitivity and response time in a large range and the gas sensing performances with both high sensitivity and fast response have been obtained only by controlling microstructures of the porous films. High stability, good reproducibility, and selectivity of the sensing performance have been achieved. Further, micro/nanostructured porous film sensors with desired sensing performances are designed and fabricated. This work could be important towards practical applications of micro/nanostructured porous-film-based sensors in the near future.

The flapping of a flag in the wind is a classical fluid-structure problem that concerns the interaction of elastic bodies with ambient fluid. We focus on the desirable experimental results of the flow around the flapping flag. By immersing the elastic yet self-supporting heavy flag into water flow, we use particle image velocimetry (PIV) techniques to obtain the whole flow field around the midspan of the flag interacting with a fluid in periodic state. A unique PIV image processing method is used to measure near-wall flow velocities around a moving elastic flag. There exists a thin flow circulation region on the suction side of the flag in periodic state. This observation suggests that viscous flow models may be needed to improve the theoretical predictions of the flapping flag in periodic state, especially in a large amplitude.

This paper examines the transition process in a boundary layer on a rotor blade under the impingement of an inlet guide vane wake. The effects of wake strengths and the reduced frequency on the unsteady boundary layer development on a low-speed axial compressor were investigated using particle image velocimetry. The measurements were carried out at two reduced frequencies (fr = fIGVS0/U2i, fr = 1.35, and fr = 0.675) with the Reynolds number, based on the blade chord and the isentropic inlet velocity, being 97 500. At fr = 1.35, the flow separated at the trailing edge when the wake strength was weak. However, the separation was almost totally suppressed as the wake strength increased. For the stronger wake, both the wake’s high turbulence and the negative jet behavior of the wake dominated the interaction between the unsteady wake and the separated boundary layer on the suction surface of the airfoil. The boundary layer displacement thickened first due to the negative jet effect. Then, as the disturbances ...

In this paper, a general low-cost and substrate-independent chemical etching strategy is demonstrated for the synthesis of ZnO nanotubes array. During the chemical etching, the nanotubes array inherits many features from the preformed nanorods array, such as the diameter, size distribution, and alignment. The preferential etching along c axis and the surfactant protection to the lateral surfaces are considered responsible for the formation of ZnO nanotubes. This surfactant-assisted chemical etching strategy is highly expected to advance the research in the ZnO nanotube-based technology.

The double-layer hetero-apertured porous films with hierarchical micro/nanoarchitectures were fabricated on a desired substrate, based on a simple and flexible strategy alternately using the monolayer colloidal crystal with different sizes of colloidal spheres as templates. Such films are of biperiodic ordered structures and can be fully lifted off from the substrate and present a freestanding property. The structures and morphologies of the films can be controlled by combination of the colloidal monolayers with different sphere sizes. The corresponding gas sensing devices were also built. Representatively, the In(2)O(3) hierarchically micro/nanostructured porous film-based sensors have shown both higher sensitivity and much faster response to NH(3) atmosphere than the corresponding conventional nanostructured ones. Importantly, the gas-sensing parameters (i.e., response time and the sensitivity) can be well-controlled separately in a large range simply by changing the pore sizes in different layers of the porous film. Further, for the application, a diagram of gas-sensing parameters (t(R)-S diagram) was presented, which can not only give a measurement of sensing performances but also well guide design and fabrication of the hierarchically structure-based sensors with desired sensing performances. This work is an important step toward the practical application of the nanostructured porous film sensors.

Two-dimensional double-layer micro/nanostructured ZnO disks were fabricated in large quantity by a facile solution route at 50 °C within a short reaction time using citrate as crystal growth modifiers. The disks are round-shaped and double-layer nanostructured, about 2 μm in diameter and 400 nm in thickness, which is a new member of the nanostructured ZnO family. Polar-field-induced growth is proposed for the formation of the double-layer ZnO disks. Photoluminescence measurements indicate that there is a strong violet emission in such disks, which is expected to find applications in next generation nanostructured optoelectronic devices.

Porous ZnO nanotubes have been synthesized via a facile hydrothermal method based on a preferential etching strategy. The nanotubes have a nearly homogeneous size with about 250 nm diameter, 40 nm wall thickness, and 500 nm length. Nanoholes with diameters ranging from tens to hundreds of nanometers were created on the side wall of the tubular structure. Formation of the porous ZnO nanotubes resulted from preferential etching along the c axis and relatively slow etching along the radial directions due to the polar feature of the ZnO crystal. Superior photocatalytic activity of the porous ZnO nanotubes in the degradation of methyl orange compared to the other samples has been demonstrated, and the origin is mainly ascribed to the scattered nanoholes on the wall of the porous nanotubes. The influence factors and formation mechanism of the porous ZnO nanotubes were analyzed and discussed.

Base do na monolayer polystyrene (PS) colloidal crystal, large-scale two-dimensional (2D) hierarchical porous silica (orderly arranged macropores and disordered mesopores in its skeleton) with a high specific surface area was fabricated by the sol–gel technique. Such material has demonstrated superhydrophilicity with a water contact angle (CA) of 5 ◦ and superhydrophobicity with a water CA of 154 ◦ after surface modification with fluoroalkylsilane. More interestingly, the water CA can be increased to 165 ◦ using a heat-deformed PS template, which suggests that the superhydrophobicity can be controlled by the template with different heat-deformed extents. Such silica films have applications in fields of adsorbent, catalytic, chromatographic support, microseparator and microfluid devices. (Some figures in this article are in colour only in the electronic version)

The LSM-coated BSCF cathode with 3D core-shell architecture had been fabricated by the solution impregnation technology and presented the excellent CO2-poisoning resistance at the operating temperature. The LSM shell limited the combination of CO2 and BSCF, making that the 3D core-shell cathode present the great CO2-poisoning resistance. The three-electrode measurement was carried out to investigate the ORR mechanism. As the intervention of LSM shell, the LSM-coated BSCF presented the different ORR rate-determining step comparing with the BSCF cathode. The formation of lattice oxygen was the rate-determining step for the LSM-coated BSCF cathode, while molecular oxygen surface adsorption for the BSCF cathode. In addition, the electrochemical stability was promoted greatly with the protection of LSM shell. The LSM-coated BSCF cathode could get the stable state at about 11 h under cathodic current passage of 400 mAcm-2 at 650 °C, while it was about 70 h for the BSCF cathode. The excellent electrochemical performance and CO2-poisoning resistance made that the LSM-coated BSCF cathode appears to be a promising cathode for IT-SOFCs.

The inner tubes of carbon nanotubes (CNTs) have a significant promotion effect on the electrocatalytic activity of Pd nanoparticles (NPs) for the ethanol oxidation of direct alcohol fuel cells (DAFCs) and Pd NPs supported on CNTs with 3–7 walls show a much higher activity as compared to that supported on typical single-walled and multi-walled CNTs.

Ordered porous carbon films with tunable pore diameters, immobilized with glucose oxidase (GOD) have been fabricated and employed for the construction of a biosensor for glucose molecules. The as-prepared porous films have large specific surface areas and highly ordered porous structure with uniform pore sizes, which are critical for the immobilization of large amounts of GOD and support the promotion of heterogeneous electron transfer. The developed biosensors give enough room for the encapsulation of a high amount of GOD molecules and show excellent biosensing performance with a linear response to glucose concentration ranging from 0.5 to 9 mM and a detection limit of 1.5 μM. It is also demonstrated that the sensitivity of the biosensor can be easily tuned by modulating the pore size of carbon film as it dictates the amount of immobilization of GOD in the porous channels. The fabricated carbon-film-based biosensor has a good stability and a high reproducibility, which opens the gateway for the commercialization of this excellent technology. Refereed/Peer-reviewed

Well-ordered meso-macroporous carbon nitride film fabricated via a simple and flexible template replication method by using the P123 block copolymer and polystyrene spheres as dual templates shows selective sensing performance for acetic acid but after treating the surface of the film with UV light and oxygen, the selectivity of sensing can be tuned for basic molecules. Refereed/Peer-reviewed

Dye-sensitized solar cells (DSSC) have received considerable attention owing to their low preparation cost and easy fabrication process. However, one of the drawbacks that limits the further application of DSSC is their poor stability, arising from the leakage and volatilization of the liquid organic solvent in the electrolyte. Therefore, to improve the long-term stability of DSSC, polymer gel electrolyte was studied to replace the conventional liquid electrolyte in this work. The results show that compared to liquid electrolyte, DSSC with polymer gel electrolyte has a smaller short-circuit current (Jsc), which decreases with the increase of the polymer gelator. Nevertheless, with the employment of the polymer gel electrolyte, there is a significant enhancement of open-circuit voltage (Voc), and it increases with the increase of the polymer gelator content. The highest Voc, up to 0.873 V, can be obtained for DSSC with a 30% polymer gelator content. The impact of the polymer gel electrolyte on the photovoltaic performance of DSSC, especially on Voc, was studied by analyzing the charge-transfer kinetics in the polymer gel electrolyte. Furthermore, the influence of the polymer gel electrolyte on the long-term stability of DSSC was also investigated.

The formation of an interface between Bi${}_{2}$O${}_{3}$, Fe${}_{2}$O${}_{3}$, BiFeO${}_{3}$, Bi${}_{0.5}$Na${}_{0.5}$TiO${}_{3}$, and the high work function metallic RuO${}_{2}$ is studied using photoelectron spectroscopy with in situ RuO${}_{2}$ deposition. Schottky barrier heights are derived and the valence band maximum energies of the studied materials are aligned with respect to each other as well as to other functional oxides like SrTiO${}_{3}$ and PbTiO${}_{3}$. The energy band alignment follows systematic trends compared to a large number of oxides, and can be understood in terms of the contribution of Fe $3d$ and Bi $6s/6p$ (lone pair) orbitals to electronic states near the valence band maximum. The results indicate that the valence band maxima are largely determined by the local environment of the cations, which allows to estimate valence band maximum energies of oxides with multiple cations from those of their parent binary compounds. The high valence band maximum of BiFeO${}_{3}$ is consistent with reported $p$-type conduction of acceptor doped material, while the high conduction band minimum makes $n$-type conduction unlikely.

Homogenous thin films are preferable for high-performance gas sensors because of their remarkable reproducibility and long-term stability. In this work, a low-temperature fabrication route is presented to prepare crack-free and homogenous metal oxide periodic porous thin films by oxygen plasma irradiation instead of high temperature annealing by using a sacrificial colloidal template. Rutile SnO2 is taken as an example to demonstrate the validity of this route. The crack-free and homogenous porous thin films are successfully synthesized on the substrates in situ with electrodes. The SnO2 porous thin film obtained by plasma irradiation is rich in surface OH groups and hence superhydrophilic. It exhibits a more homogenous structure and lower resistance than porous films generated by annealing. More importantly, such thin films display higher sensitivity, a lower detection threshold (100 ppb to acetone) and better durability than those that have been directly annealed, resulting in enhanced gas-sensing performance. The presented method could be applied to synthesize other metal oxide homogenous thin films and to fabricate gas-sensing devices with high performances.

A-site cation ordered double perovskite cathode, especially LnBaCo2O5+δ series, have drawn great interests due to their faster oxygen ion diffusion and higher electrical conductivity[1-3].As a promising SOFC cathode with highest oxygen diffussion coefficient (D*) among the mixed ionic and electronic conductor (MIEC)[4], PrBaCo2O5+ δ exhibits great oxygen reduction reaction(ORR) catalytic activity and electrochemical performance[5] .Here we proposed a gradient-porosity PrBaCo2O5+ δ SOFC cathode. The top-layer of the cathode was highly porous while the sub-layer much denser. Gases’ adsorption plays important roles in ORR process, thus pores’ distribution has great influence on cathode’s performance[6]. Higher porosity means more ORR active regions but less ions paths, and vice versa. There is a trade-off between gases path and ions path. And gradient-porosity cathode aiming at increasing gases adsorption region at gas-contacted surface of cathode about 3-5um depth, at the meantime ensure ions’ fast transfer by enlarge cathode-electrolyte contacted regions. This targeted modification will enhanced cathode’s ORR activity and can be adopted in SOFC’s practical application. [1] Q. Zhou, T. He, Y. Ji, J. Power Sources, 185,754-758 (2008) . [2] A. Chang, S.J. Skinner, J.A. Kilner, Solid State Ion, 177,2009-2011 (2006) . [3] S. Choi, S. Yoo, J. Kim, S. Park, A. Jun, S. Sengodan, J. Kim, J. Shin, H.Y. Jeong, Y. Choi, Sci. Rep, 3 (2013). [4] A. Tarancón, M. Burriel, J. Santiso, S.J. Skinner, J.A. Kilner, J. Mater. Chem, 20,3799-3813 (2010) . [5] D. Chen, R. Ran, K. Zhang, J. Wang, Z. Shao, J. Power Sources, 188,96-105 (2009) . [6] S. Skinner, J. Kilner, Solid State Ion, 135,709-712 (2000) .

A simple photo-induced approach is developed for the preparation of COOH functionalized meso-macroporous carbon films with tunable pores without using any inorganic mesoporous silica templates, which show excellent sensing selectivity for aniline and the selectivity can be enhanced upon increasing COOH functional groups. Refereed/Peer-reviewed

Introducing the rank-weight method into the basic ant colony optimization (ACO), we use the modified ACO to optimize the weights and thresholds value of neural networks (NN). And when the BPNN is being trained, this method can solve the disadvantages of running into the minimum easily, and enhance the convergence speed. So we get a heuristic method, which is good at time efficiency and derivation efficiency that is ACOrw-BP. Then this method was used to identify the speed of the motor in direct torque control (DTC).The results of the simulation showed that: the modified ACOrw-BP neural network not only has the ability of mapping widely, but also enhancing the operation efficiency obviously. The speed of the motor can be identified accurately by this method, and the result is good. So, it implements the direct torque control of speed sensorless.

In this study, a promising alternative method for addressing grain boundary issues in hematite (α-Fe2O3)-based photoanodes is presented. The porous α-Fe2O3 films are prepared by dip coating a polymerizable precursor onto fluorine-doped tin oxide (FTO) substrates. The photoelectrochemical (PEC) performance of α-Fe2O3 photoanodes is characterized and optimized through controlling the annealing temperature and the number of deposition cycles. Samples of improved crystallinity consisting of a layer of hematite particles of 50 nm in diameter exhibit highest photoresponses of 1.04 mA cm−2 at 1.23 V versus a reversible hydrogen electrode (RHE), and 2.0 mA cm−2 before the dark current onset at 1.7 VRHE. This study indicates that the PEC performance of hematite can be enhanced greatly by an improved crystallinity, particle texture, and a better control of grain boundary effects.

A simple and flexible strategy is presented for synthesis of mono or multi-layer nanostructured ordered porous films on any desired substrates with flat or even curved surface, based on the fact that polystyrene sphere colloidal monolayer on glass substrate can lift off and floated on some precursor solutions, which can, in turn, be transferred onto any substrates by picking it up. SnO/sub 2/ ordered nanostructured porous films are thus successfully synthesized on the cylindrical surface, the concave surface and the spherical surface, respectively, just by taking the easily acquired SnCl/sub 4/ solution as precursor. More importantly, the mono and multi-layer porous films are also directly synthesized on commercially supplied ceramic or porcelain tubes which are used for the substrate of gas sensors. And hence, the SnO2 ordered nanostructured porous gas-sensor is constructed. Sensitivity of the sensor can be easily controlled by changing the sizes of polystyrene spheres. Such method is universal and suitable for synthesis of many other oxides or doped porous films, mesoporous/macroporous gas sensor films and even the hetero-multi-layer porous films on the curved surfaces just by changing the compositions of the precursors or alternatively repeating this strategy. This strategy provides a good way to construct nanostructured gas-sensors and practical possibility of the nanostructured devices in the near future.

Polymer electrolytes, acting as an ionic solid-state conducting phase, have been demonstrated as promising charge carrying mediators for energy storage devices. However, the large majority of polymer electrolyte studies are focused on cation transportation and little consideration has been given to the investigation of the anion transportation mechanism. In this study we focus on the individual ionic transportation mechanisms in polymer electrolytes for potential application in dye-sensitized solar cells (DSSCs). To explore the ionic transportation mechanism, polymer electrolytes with different ion concentrations were studied. The influence of ion concentration on the structure of the polymer electrolytes was elucidated using X-ray diffraction (XRD) and Raman spectroscopy. Additionally, the temperature and composition dependence of the ionic conductivity and restricted ion diffusion coefficient of the polymer electrolytes were studied to gain an insight into the ionic transportation mechanism. The behavior of the anion transportation was further discussed via the addition of I2 into the polymer electrolytes. The results imply that the disorder and flexibility of the polymer matrix are favorable for ionic transportation, and that mass transportation can be facilitated by increasing the I2 concentration in the polymer electrolyte, which could be applied in DSSCs.

We report for the first time the demonstration of high intensity sonication treatment as a simple and effective way to fundamentally improve the performance of nanoparticles for photoelectrochemical (PEC) water splitting. The capability of making highly photoactive nanoparticles by high intensity sonication is highly appreciated to open up new opportunities in various areas, including PEC water splitting, dye-sensitized solar cells, and photocatalysis.

The density of states and optical properties of N, S, and (N, S)-doped anatase TiO2 are calculated based on the density functional theory. The results indicate that the doping S atoms occupy the Ti-atom sites in anatase TiO2 lattice. The mixing of O 2p, N 2p, S 3p, and Ti 3d states in the forbidden gap of (N, S)-codoped TiO2 can result in the higher visible-light photocatalytic activities than those monodoped TiO2. For comparison, (N, S)-codoped TiO2 was also synthesized by one-step hydrothermal method, and the optical absorption spectra obtained by experiments verified the reliability of our calculation.

Based on a sol-gel technique and the colloidal monolayer template, ion-doped SnO2 ordered porous films were fabricated, and the corresponding gas-sensing properties were studied. The sensitivity to the given test gases strongly depends on the doping species and doping amount. Importantly, when the doping amount is 1% M, the Cr+3 and Pd+2 doped porous films demonstrate a greatly enhanced sensitivity and strong selectivity to ethanol and ammonia, respectively. The improved sensing properties are attributed to the doping-induced surface modification of the films. Such ion-doped porous films are expected to bring new opportunities for application of future porous film-based gas sensors.

In this paper, the general synthesis of two-dimensional (2D) ordered porous micro/nanostructured arrays by a layer-by-layer strategy based on the 2D colloidal template transfer are systematically studied. Using such a strategy, various 2D ordered porous films including hetero-pore sized, heterostructured and ion-doped porous films can be fabricated on any desired substrates. Moreover, the film thickness, chemical composition and packing geometry of the porous film also demonstrate a good manner of controllability. The formation mechanisms of these structures are briefly discussed. This synthetic route is highly expected to advance the synthesis of functional patterned 2D ordered porous nanostructures, which will find potential applications in sensors, optoelectronic devices, separation science and smart filters/flowmeters.

A high-temperature anisotropic silicon-etching strategy is demonstrated to steer the growth of the horizontally localized parallel Zn(2)SiO(4) nanowires.

Hexagonal nanopillars with a single InGaAs/GaAs quantum well (QW) were fabricated on a GaAs (111) B substrate by selective-area metal-organic vapor phase epitaxy. The standard deviations in diameter and height of the nanopillars are about 2% and 5%, respectively. Zincblende structure and rotation twins were identified in both the GaAs and the InGaAs layers by electron diffraction. The excitation-power-density-dependent micro-photoluminescence (mu-PL) of the nanopillars was measured at 4.2, 50, 100 and 150 K. It was shown that, with increasing excitation power density, the mu-PL peak's positions shift to a higher energy, and their intensity and width increase, which were rationalized using a model that includes the effects of piezoelectricity, photon-screening and band-filling. It was also revealed that the rotation twins significantly reduce the diffusion length of the carriers in the nanopillars, compared to that in the regular semiconductors.