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Here, we report an inexpensive and highly catalytic carbon/AgNWs counter electrode for flexible dye-sensitized solar cells (DSSCs). In order to reduce the process time, an organic surfactant is added to disperse the carbon composites. Then, a uniform catalytic layer can deposit on the silver nanowire (AgNW) transparent conductive electrode. Ultimately, a low temperature UV irradiation post-treatment is proposed to clean the surface of the catalytic layer. Through the electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) curve and Tafel curve, it can be established that this carbon/AgNWs counter electrode exhibits high catalytic activity than that of Pt/ tin-doped indium oxide (ITO) electrode. In addition, the current density–voltage characteristic curves also prove that the as-assembled DSSC has a superior photoelectrical conversion efficiency.

The high throwing power (TP) value is one of the most important parameters for the Cu electroplating of through-holes in flexible printed circuit (FPC). It was found that an ultra-high TP value could be obtained using a specific suppressor, i.e., iodonitrotetrazolium chloride (INT) in the electrolyte. The ultra-high TP value was attributed to fast-consumption of this suppressor instead of traditional convection-dependence adsorption mechanism. A consumption model was built and simulated to clarify the formation of the ∆θ, i.e., the difference of suppressor fractional coverage between the entrance and center of through-holes sidewalls. It revealed that the TP, proportional to the ∆θ, was determined by the consumption rate of a suppressor. This simulation results were well consistent with the results of electroplating using INT with different concentration. The electrochemical analysis verified the characteristics of fast consumption of INT due to the reduction reaction. The difference of residual INT between the entrance and center of the plated through-holes confirmed the occurrence of ∆θ. These results supported the opinion that the ultra-high TP value was obtained by fast-consumption mechanism of INT suppressor.

A highly porous nitrogen-doped carbon sphere (NPC) electrocatalyst was prepared through the carbonization of biomass carbon spheres mixed with urea and zinc chloride in N2 atmosphere. The sample carbonized at 1000 °C demonstrates a superior oxygen reduction reaction (ORR) performance over the Pt/C electrocatalyst, while its contents of pyridinic nitrogen and graphitic nitrogen are the lowest among samples synthesized at the same or lower carbonization temperatures. This unusual result is explained by a space confinement effect from the microporous and mesoporous structures in the microflakes, which induces the further reduction of peroxide ions or other oxygen species produced in the first step reduction to water to have the preferred overall four electron reduction ORR process. This work demonstrates that in addition to the amount or species of its active sites, the space confinement can be a new approach to enhance the ORR performance of precious-metal-free, nitrogen-doped carbon electrocatalysts.

A novel arsenic adsorbent with hydrous cerium oxides coated on glass fiber cloth (HCO/GFC) was synthesized. The HCO/GFC adsorbents were rolled into a cartridge for arsenic removal test. Due to the large pores between the glass fibers, the arsenic polluted water can flow through easily. The arsenic removal performance was evaluated by testing the equilibrium adsorption isotherm, adsorption kinetics, and packed-bed operation. The pH effects on arsenic removal were conducted. The test results show that HCO/GFC filter has high As(V) and As(III) removal capacity even at low equilibrium concentration. The more toxic As(III) in water can be easily removed within a wide range of solution pH without pre-treatment. Arsenic contaminated ground-water from Yangzong Lake (China) was used in the column test. At typical breakthrough conditions (the empty bed contact time, EBCT = 2 min), arsenic researched breakthrough at over 24,000 bed volumes (World Health Organization (WHO) suggested that the maximum contaminant level (MCL) for arsenic in drinking water is 10 mg/L). The Ce content in the treated water was lower than 5 ppb during the column test, which showed that cerium did not leach from the HCO/GFC material into the treated water. The relationship between dosage of adsorbents and the adsorption kinetic model was also clarified, which suggested that the pseudo second order model could fit the kinetic experimental data better when the adsorbent loading was relatively low, and the pseudo first order model could fit the kinetic experimental data better when the adsorbent loading amount was relatively high.

Photocatalysts with the photocatalytic “memory” effect could resolve the intrinsic activity loss of traditional photocatalysts when the light illumination is turned off. Due to the dual requirements of light absorption and energy storage/release functions, most previously reported photocatalysts with the photocatalytic “memory” effect were composite photocatalysts of two phase components, which may lose their performance due to gradually deteriorated interface conditions during their applications. In this work, a simple solvothermal process was developed to synthesize Bi2WO6 microspheres constructed by aggregated nanoflakes. The pure phase Bi2WO6 was found to possess the photocatalytic “memory” effect through the trapping and release of photogenerated electrons by the reversible chemical state change of W component in the (WO4)2− layers. When the illumination was switched off, Bi2WO6 microspheres continuously produced H2O2 in the dark as those trapped photogenerated electrons were gradually released to react with O2 through the two-electron O2 reduction process, resulting in the continuous disinfection of Escherichia coli bacteria in the dark through the photocatalytic “memory” effect. No deterioration of their cycling H2O2 production performance in the dark was observed, which verified their stable photocatalytic “memory” effect.

Recently, photoassisted charging has been demonstrated as a green and sustainable approach to successfully enhance the capacitance of supercapacitors with low cost and good efficiency. However, their light-induced capacitance enhancement is relatively low and is lost quickly when the illumination is off. In this work, a novel active material system is developed for supercapacitors with the photoassisted charging capability by the decoration of a small amount of Bi

Prussian blue analogs (PBAs) are considered as efficient catalysts for energy-related applications due to their porous nanoscale architectures containing finely disseminated active sites. Their catalytic capability can be greatly boosted by the rational design and construction of complex PBA hybrid nanostructures. However, present-day structure engineering inevitably involves additional etchant or procedure. Herein, a facile, yet controllable one-pot self-assembly strategy is introduced to prepare hierarchical core-shell polymetallic PBAs (featuring bimetallic FeMn PBAs cores and CoNi PBAs shells) with hollow nano-cages/solid nano-cube architectures. The detailed characterization of material morphology/composition, assisted with theoretical simulations, reveals the underlying formation mechanism where the key factor is the control of the nucleation rate via the use of chelating agent (citrates) and reaction kinetics. The resulting FeMn@CoNi-H compound is found to accelerate the oxygen evolution reaction activity with a low overpotential (236 mV at a current density 10 mA cm

Recently, high entropy alloy (HEA) based materials have been vigorously explored as viable catalysts in water electrolysis for their unique properties. However, the synthesis of efficient and robust high entropy catalysts remains a challenge. Here a facile and scalable approach is reported to synthesize advanced HEA (CoNiCuMnAl)/C nanoparticles from the polymetallic Metal–organic framework (MOF). The novel core-shell nanoarchitectures feature face-centered cubic HEA wrapped in ultra-thin carbon shell. The optimized catalyst (deposited upon Ni foam) boosted alkaline Oxygen evolution reaction (OER) (in 1.0 M KOH) with an ultralow overpotential of 215 mV at 10 mA/cm2 (also by a low Tafel slope of 35.6 mV dec−1). The enhanced performance is closely tied to surface reconstruction (i.e., formation of oxyhydroxide catalytic active species) and the high entropy effect, revealed by Fourier-transformed alternating current voltammetry (FTACV) and in-situ Raman spectrum analysis, in conjunction with Density Functional Theory (DFT) computations. Furthermore, the new design showed excellent long-term OER stability with negligible decay through 30 h testing (under 200 mA cm−2). The present work demonstrates the feasibility and advantage of utilizing highly efficient and durable high entropy alloys for catalyzing electrochemical water splitting process.

Nano-twinned, nanocrystalline CoCrFeNi high-entropy alloy films were produced by magnetron sputtering. The films exhibit a high hardness of 8.5 GPa, the elastic modulus of 161.9 GPa and the resistivity as high as 135.1 μΩ·cm. The outstanding mechanical properties were found to result from the resistance of deformation created by nanocrystalline grains and nano-twins, while the electrical resistivity was attributed to the strong blockage effect induced by grain boundaries and lattice distortions. The results lay a solid foundation for the development of advanced films with structural and functional properties combined in micro-/nano-electronic devices.

Metal-free polymeric carbon nitride (C3N4) photocatalysts offer attractive technological advantages over the conventional transition metal oxides or sulfides -based photocatalysts in water disinfection, but their antimicrobial activities are limited by their rapid charge carrier recombination and low specific surface areas. By controlling photocatalytic pathways, we obtained in amino-rich holey ultrathin g-C3N4 nanosheets (AHUCN) a highly efficient inactivation rate against E-coli, which is the highest among the monolithic g-C3N4 and exceeds the antibacterial performance of the most of the previously reported g-C3N4-based photocatalysts. Both the experiments and theoretical calculations demonstrated that the high photocatalytic disinfection performance of AHUCN was derived from the synergistic advantages of their unique holey ultrathin structure and the amino - rich surface in controlling the charge separation and transfer, and most importantly in increasing the photo-production of the dominant antibacterial species, H2O2. From the analysis of the reactive oxygen species and rotating disk electrode (RDE) measurements, it was found that the presence of abundant surface amino groups enabled the switch of the oxygen-reduction pathway from the two-step single-electron indirect reduction on holey ultrathin g-C3N4 nanosheets (HUCN) to the one-step two-electron direct reduction on AHUCN. The switch of the H2O2 production pathway not only facilitated the separation of photogenerated electron-hole pairs but also promoted the generation of reactive oxygen species, greatly enhancing photocatalytic disinfection efficiency.

Single-crystal Sn/Cu solder joints with (001), (101), (301) and (100) plane of Sn as the interfaces were prepared for studying the relation between orientation of Sn and electromigration. The growth of interfacial intermetallic compounds was found to strongly depend on the Sn grain orientation. When the c-axis was parallel to the current direction, a severe polarity effect was observed, while the c-axis of Sn off the current direction, the polarity effect became less pronounced. For (101) and (301) orientation samples making a 28.6° and 58.6° angles with c-axis of Sn, asymmetrical IMCs layer growth at the anode interface, downward sloping serrated edges of Cu dissolution groove at the cathode and granular Cu6Sn5 growth at the surface were observed, while these morphological features were not found in (001) and (100) samples making a 0° and 90° angles with c-axis of Sn. It is suggested that when the c-axis of β-Sn was off the current direction, the direction of Cu atoms diffusion is shifted to the c-axis of tin grain under the electromigration driving force.

The orientations of Cu 6 Sn 5 grains grown on (001), (011) and (301) Sn single crystals plated with Cu were investigated under electrical loading. After current stressing, anode Cu 6 Sn 5 grains preferred the following orientation relationships with Sn: {-111} Sn //{01-10} Cu6Sn5 , 〈0-11〉 Sn //〈2-1-13〉 Cu6Sn5 . Four different Cu 6 Sn 5 orientations were found in anode of (001) Sn/Cu joints, where the coherent interface, {-111} Sn //{01-10} Cu6Sn5 , makes a 37.7° angle with the initial interface. Only two orientations were found in the (301) Sn/Cu joint, where the undiscovered orientations with coherent interfaces were nearly vertical to the initial interface. In (101) Sn/Cu joints, the Cu 6 Sn 5 grains with a 25.6° angle between coherent interfaces and the initial interface are much more numerous than with a high angle (60.8°). The results show that Cu 6 Sn 5 grains with a low angle between the coherent interfaces and the initial interface form preferentially during the electromigration process. In addition, cline Cu 6 Sn 5 grain boundaries were observed. A thermodynamics model based on coherent interfacial energy was presented to explain the relations and the formation of cline Cu 6 Sn 5 grain boundaries. It suggests that only when the angle between the coherent interface and the initial interface is lower than a threshold value will the relation form for the lower free energies.

Highly efficient photocatalytic reduction of environmental pollutants requires the enrichment of photogenerated electrons on the photocatalyst’s surface. Thus, proper material design and modification are needed to efficiently separate photogenerated electron/hole pairs and achieve their oriented migrations for the enrichment of photogenerated electrons on their surface. In this work, a modified photo-deposition process was developed which successfully deposited silver nanoparticles selectively on {1 0 1} facets of TiO 2 nanocrystals with co-exposed {0 0 1}/{1 0 1} facets. The synergistic effect of crystal facet engineering and the selective deposition of silver nanoparticles on {1 0 1} facets largely enhanced the separation of photogenerated carriers and enriched the presence of photo-generated electrons onto the surface of TiO 2 to a net negative-charged surface. A strong photocatalytic reduction capability of the sample was demonstrated by its superior photocatalytic reduction activity on aqueous nitrate under a simulated solar illumination. The removal ratio of aqueous nitrate reached ∼95%, and most of the reduction product was the desirable N 2 with the selectivity over 90%. These TiO 2 nanocrystal with co-exposed {0 0 1}/{1 0 1} facets and silver modification on {1 0 1} facets could also effectively remove both nitrate and various organic pollutants from water simultaneously.

New under bump metallization (UBM) is required for future microelectronics to minimize reliability concerns with solder interconnects. In this study, electroless FeP film was prepared as UBM. Solderability of electroless NiP, electrodeposite Fe and electroless FeP films with eutectic SnAgCu solder was investigated by static wetting tests and wetting balance measurements. Results revealed that the solderability of NiP film has almost no change with thermal aged for the film in air atmosphere increasing. The contact angles for FeP and Fe films with SnAgCu solder increased and the maximum wetting force decreased with heating time increasing from 0 h, 48 h, 89 h–160 h at 180 °C. But the solderability of FeP film was found to be better than those of NiP and Fe whether the films in base or thermal aged at 180 °C for 89 h. Even after thermal aged in air atmosphere at 180 °C for 160 h, the FeP also performed the smallest contace angle compared with the NiP and the Fe. Oxide layer on the surface of FeP was much easier to be removed by rosin mildly activated flux during reflow process because loose structure. It was proved to be the key for the highly solderability of electroless FeP.

One-dimensional nanomaterials may organize into macrostructures to have hierarchically porous structures, which could not only be easily adopted into various water treatment apparatus to solve the separation issue of nanomaterials from water but also take full advantage of their nanosize effect for enhanced water treatment performance. In this work, a novel template-based process was developed to create Mn3O4/CeO2 hybrid nanotubes, in which a redox reaction happened between the OMS-2 nanowire template and Ce(NO3)3 to create hybrid nanotubes without the template removal process. Both the Ce/Mn ratio and the precipitation agent were found to be critical in the formation of Mn3O4/CeO2 hybrid nanotubes. Because of their relatively large specific surface area, porous structure, high pore volume, and proper surface properties, these Mn3O4/CeO2 hybrid nanotubes demonstrated good As(III) removal performances in water. These Mn3O4/CeO2 hybrid nanotubes could form paper-like, free-standing membranes spontaneously b...

Considering the current induced voids flow will accelerate the creep strain rate and lower the strength of the solder, a current induced activation energy change, ΔQe is added in the Anand model. A lifetime prediction model was constructed based on linear damage rule for the current-thermal cycling coupling test. To verify the accuracy of the model, mean-time-to-failure (MTTF) of copper pillar has been experimentally and analytically investigated under the combination of thermal cycling with temperature range of −40 to 125 °C and a superimposed electric current with current densities of 17.4–22.4 × 104 A/cm2. The experimental results reveal that the MTTF sharply decreases with the increasing current density. The acceleration factors are calculated, which is consistent well with the prediction model.

The electromigration (EM) lifetime of copper pillars were investigated by orthogonal tests. According to the Black’s mean-time-to-failure equation, the activation energy and exponent of current density were calculated to be 0.88 eV and 1.64, respectively. The microstructure evolution of the joints under current stressing was observed. It was found that the Sn solder was usually depleted before the joint failed, which means the joint was only composed of Cu6Sn5 and Cu3Sn phases as a Cu/Cu3Sn/Cu6Sn5/Cu3Sn/Cu structure after a period of EM test. Three failure modes were observed: failure along the Cu/Cu3Sn interface at the cathode side, failure along the Cu/Cu3Sn interface at the anode side and brittle fracture through the IMCs. The percentages of these three failure modes are 55, 24 and 21 %, respectively. The formation of Kirkendall voids was suggested to be the key factor for the EM failure of the Cu pillar joints. Before the Sn solder was depleted, voids were mainly formed at the Cu6Sn5/Sn interface at the cathode, which is dominated by the Cu flux induced by current; while after the Sn solder was depleted, voids formation is dominated by the chemical diffusion.

Sn–Ag–Cu solder interconnects were made by solidifying the solder balls in a magnetic field and subsequently tested for their electromigration behavior. The orientation of the tin grains was analyzed by electron backscattered diffraction. It was found that the c-axis of Sn grain tended to rotate away from the direction of the magnetic field during solidification, resulting in an enhanced electromigration resistance for the solder joint when the current was applied along the direction of the magnetic field, as evidenced by a smaller electromigration-induced polarity effect in the growth of the interfacial intermetallic compound. Such a reduced polarity-effect of electromigration is shown to agree well with the anisotropy in the diffusivity of the active diffusion species, Cu, in the tetragonal Sn. The difference of free energy change caused by the anisotropy in the magnetic susceptibility of the tetragonal Sn during solidification is suggested to be the main factor for this phenomenon.

An in situ microscopy technique was developed to observe in real time the photocatalytic inactivation process of Saccharomyces cerevisiae (S. cerevisiae) cells by palladium-modified nitrogen-doped titanium oxide (TiON/PdO) under visible light illumination. The technique was based on building a photocatalytic micro-reactor on the sample stage of a fluorescence/phase contrast microscopy capable of simultaneously providing the optical excitation to activate the photocatalyst in the micro-reactor and the illumination to acquire phase contrast images of the cells undergoing the photocatalytic inactivation process. Using TiON/PdO as an example, the technique revealed for the first time the vacuolar activities inside S. cerevisiae cells subjected to a visible light photocatalytic inactivation. The vacuoles responded to the photocatalytic attack by the first expansion of the vacuolar volume and then contraction, before the vacuole disappeared and the cell structure collapsed. Consistent with the aggregate behavior observed from the cell culture experiments, the transition in the vacuolar volume provided clear evidence that photocatalytic disinfection of S. cerevisiae cells started with an initiation period in which cells struggled to offset the photocatalytic damage and moved rapidly after the photocatalytic damage overwhelmed the defense mechanisms of the cells against oxidative attack.

Blue algae blooms could cause the indiscriminate killing of fish/invertebrates in water and the destruction of the local ecological equilibrium. The release of cyanotoxins by blue algae cells could kill livestock and cause various health problems to human beings. The highly effective photocatalytic disinfection of Anabaena sp. PCC 7120 as a representative blue algae specie under visible light illumination was demonstrated on a visible-light-activated palladium oxide-modified nitrogen-doped titanium oxide (TiON/PdO) nanoparticle photocatalyst. The large release of substances in blue algae cells, such as chlorophyll a and various ions, and severe damages on their cell wall/membrane clearly demonstrated the photocatalytic disinfection on blue algae by TiON/PdO nanoparticles under visible light illumination was an irreversible process. TiON/PdO nanoparticles also demonstrated a highly efficient photocatalytic degradation of a typical cyanotoxin, Microcystin LR, under visible light illumination. Thus, the photocatalytic treatment by TiON/PdO nanoparticles could effectively disinfect blue algae and degrade cyanotoxins under visible light illumination at the same time, which makes it attractive as an environmentally friendly and cost-effective alternative to current blue algae treatment practices.

Aqueous ammonium–ammonia (NH 4 + –NH 3 ) is a commonly found pollutant in industrial and domestic wastewater, which poses a great threat to both the environment and the human health. Photocatalytic treatment had been proved to be an efficient approach to oxidize aqueous NH 4 + –NH 3 for its removal. However, most current researches still suffer from the requirements of UV illumination and strong alkaline environment, low removal rates, and high ratios of toxic oxidation by-products of NO 3 − and NO 2 − . In this study, palladium-modified nitrogen-doped titanium oxide (TiO 2− x N x /PdO) nanoparticles were synthesized by a simple sol–gel process, which demonstrated an effective photocatalytic removal of aqueous NH 4 + –NH 3 under visible light illumination. By optimizing the reaction conditions, a high removal rate of over 90% could be achieved by TiO 2− x N x /PdO nanoparticles under only visible light illumination with the major product of N 2 , and the production of toxic photocatalytic oxidation by-products of NO 3 − and NO 2 − was minimized. The real time solution pH was found to be critical for the photocatalytic oxidation of aqueous NH 4 + –NH 3 . By keeping the solution pH constantly at ∼8, the effective photocatalytic removal of aqueous NH 4 + –NH 3 in a weak alkaline solution was achieved for the first time.

The creation of photocatalysts with controlled facets has become an important approach to enhance their activity. However, how the formation of heterojunctions on exposed facets could affect their photocatalytic performance ranking had not yet been investigated. In this study, Cu2O@TiO2 core-shell structures were created, and Cu2O/TiO2 p-n heterojunctions were formed on various exposed facets of Cu2O cubes, Cu2O cuboctahedra, and Cu2O octahedra, respectively. These Cu2O@TiO2 polyhedra demonstrated an enhanced photocatalytic degradation effect on Methylene Blue (MB) and 4-nitrophenol (4-NP) under visible light illumination, because of the enhanced charge carrier separation by the formation of Cu2O@TiO2 p-n heterojunctions. It was further found that their photocatalytic performance was also facet-dependent as pure Cu2O polyhedra, while the photocatalytic performance ranking of these Cu2O@TiO2 polyhedra was different with that of their corresponding Cu2O polyhedron cores. By the combination of optical property measurement and XPS analysis, the energy band alignments of these Cu2O@TiO2 polyhedra were determined, which demonstrated that Cu2O@TiO2 octahedra had the highest band offset for the separation of charge carriers. Thus, the charge-carrier-separation-driven force in Cu2O@TiO2 polyhedra was different from their corresponding Cu2O polyhedron cores, which resulted in their different surface photovoltage spectrum (SPS) responses and different photocatalytic performance rankings.

Hydrous manganite (MnOOH) nanorods were synthesized by a simple precipitation process in ethanol at room temperature, which eliminated high temperature calcination or a hydrothermal process in the creation of most manganese oxide-based adsorbents and resulted in low energy consumption and subsequently low production cost. These MnOOH nanorods had a high specific surface area at ∼165.9 m2 g−1 and their total pore volume was ∼0.561 cm3 g−1, which was beneficial to their arsenic removal performance. These MnOOH nanorods demonstrated a superior As(III) removal performance from an aqueous environment. At near neutral conditions (pH ∼ 7), their arsenic adsorption capacity was over 431.2 mg g−1, which was among the highest reported values in the literature. The superior As(III) removal performance of these MnOOH nanorods relied on the adsorption and subsequent oxidation of As(III) to less mobilized/toxic As(V), and its fixation on their surface to form inner-sphere arsenic surface complexes.

Parameters of stirring rate and temperature were designed based on electrochemical testings of cathodic polarization, electrochemical impedance spectroscopy and defferential capacitance. At the same time electrochemical action of diamond particles in the bath was studied. Interface force per unit area between particle and cathode was calculated in order to analyse the mechanism of composite electrodeposition. And then Ni-diamond composite coatings with 1.47–15.6 wt.% particle content were prepared by composite electrodeposition technique in typical Watt's bath. Result of electrochemical measurements revealed that mass fraction of codeposited diamond particles at medium stirring rate is higher than those of high and low stirring rate. Technics experiments confirmed the foretaste well. It was proved that electrochemical testing is significant for parameter designment. It was also detected that fraction of coverage θ NF which had effect on non-Faraday admittance could reflect more efficiently on particle content in coating compared with fraction of coverage θ F which interfered with Faraday admittance. Interface force per unit area was found to be the key for particle to entry into coating since 3.57% particles were rooted in matrix metal at just 0.0252% coating thickness/particle size. Interim stirring designed according to interface force mechanism increased the weight percentage of diamond particles in coating. The mechenism could explain the effect of particle size on particle content in coating. Calculation results show that the interface force per unit area for Ni-diamond system was close to 3.3 × 10 3 N/m 2 . Furthermore, composite electrodeposite process can be divided into three steps. Firstly, diamond particles adsorbing positive charges are direct transported toward cathodic surface due to stirring. Secondly, a tremendous amount of particles temporary attaching on cathode are scoured back into the bath by particles in the bath and flowing solution. A few particles root quickly in coating depending on interface pressure after formation of interface between particle and fresh nickel coating with the help of high electric field intensity of electric double layer. Finally, particles are buried slowly by fresh nickel coating.

Palladium-modified nitrogen-doped titanium oxide (TiON/PdO) thin film was synthesized by the ion-beam-assisted deposition technique, which enabled a heavy nitrogen doping and the subsequent light absorption extension to ∼700 nm for a better usage of the solar spectrum. Based on TiON/PdO thin film and a phase contrast microscope, a micro-reaction chamber was developed, which allowed the simultaneous optical excitation of the photocatalytic thin film and the phase contrast image observation of cells in it. The real time, in situ observation of the photocatalytic destruction of Saccharomyces cerevisiae (S. cerevisiae), an essential eukaryotic unicellular model of living cells, was conducted with this new observation technique, which demonstrated clearly that the photocatalytic destruction effect was much stronger than the photodamage effect caused by the visible light irradiation alone in the disinfection process.

Arsenic is a highly toxic element and its contamination in water bodies is a worldwide problem. Arsenic adsorption with metal oxides/hydroxides-based adsorbents is an effective approach to remove arsenic species from water for the health of both human beings and the environment. However, no material criterion had been proposed for the selection of potential candidates. Equally puzzling is the fact that no clear explanation was available on the poor arsenic adsorption performance of some commonly used adsorbents, such as active carbon or silica. Furthermore, in-depth examination was also not available for the dramatically different competing adsorption effects of various anions on the arsenic adsorption. Through the arsenic adsorption mechanism study on these highly efficient arsenic adsorbents, we found that ionic potential could be used as a general material criterion for the selection of highly efficient arsenic adsorbents and such a criterion could help us to understand the above questions on arsenic adsorbents. This material criterion could be further applied to the selection of highly efficient adsorbents based on ligand exchange between their surface hydroxyl groups and adsorbates in general, which may be used for the prediction of novel adsorbents for the removal of various contaminations in water.

PdO loaded TiO2 hollow spheres were synthesized via first reducing Pd2+ to Pd in ethanol onto TiO2 hollow spheres by refluxing and then oxidizing Pd to PdO through calcination in air. PdO nanoparticles were distributed relatively uniformly both on the surface and in the shell/interior of these TiO2 hollow spheres, to act as potential electron/hole pair separation centers. These PdO loaded TiO2 hollow spheres demonstrated a superior photocatalytic disinfection performance on Eschetichia coil bacteria, compared with the unloaded samples or P25 TiO2 nanoparticles. Their largely enhanced photocatalytic disinfection performance could be attributed to both their unique hollow structure and the electron trapping capability of loaded PdO nanoparticles. Samples with a series of PdO loading ratios were synthesized and tested to determine the optimum PdO loading ratio, which was found to be similar to 0.4 wt.%. Below the optimum PdO loading, the photocatalytic disinfection performance increased with the increase of PdO loading ratio, while further increase of the PdO loading over 0.4% resulted in a deleterious influence on the PdO enhancement effect. The photocatalytic performance differences between Pd and PdO modified samples were also investigated. Samples with 0.4% PdO modification demonstrated a better photocatalytic disinfection effect on E. coli bacteria than samples with 0.4% Pd modification, which could be attributed to their different work functions. (C) 2014 Elsevier B.V. All rights reserved.

A novel Cu2O/TiO2 composite photocatalyst structure of Cu2O nanospheres decorated with TiO2 nanoislands were synthesized by a facile hydrolyzation reaction followed by a solvent-thermal process. In this Cu2O/TiO2 composite photocatalyst, Cu2O served as the main visible light absorber, while TiO2 nanoislands formed heterojunctions of good contact with Cu2O, beneficial to the photoexcited electron transfer between them. Their band structure match and inner electrostatic field from the p–n heterojunction both favored the transfer of photoexcited electrons from Cu2O to TiO2, which effectively separated the electron–hole pairs. Photogenerated holes on Cu2O could react with water or organic pollutants/microorganisms in water to avoid accumulation on Cu2O because of the partial TiO2 nanoislands coverage, which enhanced their stability during the photocatalysis process. Their superior photocatalytic performance under visible light illumination was demonstrated in both the degradation of methyl orange and the disi...

Thermal resistance of low-melting-temperature alloy (LMTA) thermal interface materials (TIMs) was measured by laser flash method before and after different stages of heating. The results showed that the thermal performance of the LMTA TIMs was degraded during the heating process. It is suggested that the degradation may mainly be attributed to the interfacial reaction between the Cu and the molten LMTAs. Due to the fast growth rate of intermetallic compound (IMC) at the solid–liquid interface, a thick brittle IMC is layer formed at the interface, which makes cracks easy to initiate and expand. Otherwise, the losses of indium and tin contents in the LMTA during the interfacial reaction will make the melting point of the TIM layer increase, and so, the TIM layer will not melt at the operating temperature.

Passivated n–p co-doping of niobium and nitrogen was successfully incorporated into self-organized TiO2 nanotube arrays by anodizing Ti–Nb alloys, followed with the heat treatment in a flow of ammonia gas. Nb was doped into TiO2 nanotube arrays during the anodization by substituting Ti4+ with Nb5+, while N was doped into TiO2 nanotube arrays during the heat treatment by substituting O2− with N3−. Since Nb in TiO2 enhanced the adsorption of NH3 molecules onto the nanotube arrays, Nb doping was found to promote the subsequent N doping into the anatase lattice. As predicted by first-principles band structure calculations, Nb/N co-doped titanium oxide nanotube arrays demonstrated a largely enhanced visible light response and visible light photocatalytic performance on the degradation of methylene blue, compared to TiO2 nanotube arrays or TiO2 nanotube arrays with either dopant. The passivated n–p co-doping approach may also be applied to other material systems and promise a wide range of technical applications.

Well-defined WO3·H2O hollow spheres composed of nanoflakes were successfully synthesized by a template-free solvothermal process with i-PrOH–H2O mixture solvent. In this process, the tungsten precursor was firstly hydrolyzed to form solid spheres composed of both WO3·2H2O and WO3·H2O phases. Then, these solid spheres underwent an Ostwald ripening process and the WO3·2H2O phase was dehydrated to WO3·H2O at the same time to form hollow spheres with a pure WO3·H2O phase. With appropriate calcination temperature, hollow spheres with WO3 (major) and WO3·H2O (minor) mixture phases were created. These hollow spheres with WO3 and WO3·H2O mixture phases demonstrated a largely enhanced photocatalytic activity for RhB degradation under visible light irradiation compared with either pure WO3·H2O hollow spheres or pure WO3 hollow spheres which could be attributed to the matched band structure between the WO3 and WO3·H2O phases. Thus, an effective charge carrier separation can occur between the WO3 and WO3·H2O phases of these hollow spheres under visible light irradiation, contributing to the observed largely enhanced photocatalytic performance.

A novel superparamagnetic Ag@silver-based salt photocatalyst, MFNs@SiO2@Ag4SiW12O40/Ag, was created, which demonstrated highly efficient photocatalytic performance under visible light illumination in both the degradation of methylene blue (MB) and the disinfection of Escherichia coli (E. coli) bacteria. In this composite photocatalyst, well-dispersed, superparamagnetic magnesium ferrite nanoparticles (MFNs) were used as the core because of their easy magnetic separation capability. A passive SiO2 mid-layer was used to separate MFNs and Ag4SiW12O40 and form a strong bond with silver ions for their loading after –SH surface modification. The Ag4SiW12O40 layer was subsequently formed by the reaction with silicotungstic acid to avoid the commonly adopted calcination procedure after deposition/precipitation, and silver nanoparticles were formed on the surface of Ag4SiW12O40 layer after UV irradiation to further enhance their photocatalytic performance and stability under visible light illumination. The surface modification on the passive SiO2 mid-layer and the bridging procedure for material loading developed in our approach could be readily applied to other material systems for the creation of novel composite materials with various functions.

Fusarium graminearum is the pathogen for Fusarium head blight (FHB) on wheat, which could significantly reduce grain quality/yield and produce a variety of mycotoxins posing a potential safety concern to human foods. As an environmentally friendly alternative to the commonly used chemical fugicides, a highly effective photocatalytic disinfection of F. graminearum macroconidia under visible light illumination was demonstrated on a visible-light-activated palladium-modified nitrogen-doped titanium oxide (TiON/PdO) nanoparticle photocatalyst. Because of the opposite surface charges of the TiON/PdO nanoparticles and the F. graminearum macroconidium, the nanoparticles were strongly adsorbed onto the macroconidium surface, which is beneficial to the photocatalytic disinfection of these macroconidia. The photocatalytic disinfection mechanism of TiON/PdO nanoparticles on these macroconidia could be attributed to their cell wall/membrane damage caused by the attack from reactive oxygen species (ROSs) as demonstrated by the fluorescence/phase contrast microscopy observations, while a breakage of their cell structure was not necessary for their loss of viability.

Highly porous, nanostructured zirconium oxide spheres were fabricated from ZrO2 nanoparticles with the assistance of agar powder to form spheres with size at millimeter level followed with a heat treatment at 450 °C to remove agar network, which provided a simple, low-cost, and safe process for the synthesis of ZrO2 spheres. These ZrO2 spheres had a dual-pore structure, in which interconnected macropores were beneficial for liquid transport and the mesopores could largely increase their surface area (about 98 m(2)/g) for effective contact with arsenic species in water. These ZrO2 spheres demonstrated an even better arsenic removal performance on both As(III) and As(V) than ZrO2 nanoparticles, and could be readily applied to commonly used fixed-bed adsorption reactors in the industry. A short bed adsorbent test was conducted to validate the calculated external mass transport coefficient and the pore diffusion coefficient. The performance of full-scale fixed bed systems with these ZrO2 spheres as the adsorber was estimated by the validated pore surface diffusion modeling. With the empty bed contact time (EBCT) at 10 min and the initial arsenic concentration at 30 ppb, the number of bed volumes that could be treated by these dry ZrO2 spheres reached ~255,000 BVs and ~271,000 BVs for As(III) and As(V), respectively, until the maximum contaminant level of 10 ppb was reached. These ZrO2 spheres are non-toxic, highly stable, and resistant to acid and alkali, have a high arsenic adsorption capacity, and could be easily adapted for various arsenic removal apparatus. Thus, these ZrO2 spheres may have a promising potential for their application in water treatment practice.

Phosphate removal is important in the control of eutrophication of water bodies. Adsorption is one of the promising approaches for the removal of phosphate, which could serve as a supplement for the biological phosphate removal process commonly used in the wastewater treatment industry to meet the discharge requirement when the biological performance is deteriorated from changes of operation conditions. Amorphous zirconium oxide nanoparticles were synthesized by a simple and low-cost hydrothermal process, and their phosphate removal performance was explored in aqueous environment under various conditions. A fast adsorption of phosphate was observed in the kinetics study, and their adsorption capacity was determined at about 99.01 mg/g at pH 6.2 in the equilibrium adsorption isotherm study. Commonly coexisting anions showed no or minimum effect on their phosphate adsorption performance. The phosphate adsorption showed little pH dependence in the range from pH 2 to 6, while it decreased sharply with the pH increase above pH 7. After adsorption, phosphate on these am-ZrO2 nanoparticles could be easily desorbed by NaOH solution washing. Both the macroscopic and microscopic techniques demonstrated that the phosphate adsorption mechanism of am-ZrO2 nanoparticles followed the inner-sphere complexing mechanism, and the surface hydroxyl groups played a key role in the phosphate adsorption.

By doping a proper amount of Mg2+ (∼10%) into α-Fe2O3 during a solvent thermal process, ultrafine magnesium ferrite (Mg0.27Fe2.50O4) nanocrystallites were successfully synthesized with the assistance of in situ self-formed NaCl “cage” to confine their crystal growth. Their ultrafine size (average size of ∼3.7 nm) and relatively low Mg-content conferred on them a superparamagnetic behavior with a high saturation magnetization (32.9 emu/g). The ultrafine Mg0.27Fe2.50O4 nanoadsorbent had a high specific surface area of ∼438.2 m2/g, and demonstrated a superior arsenic removal performance on both As(III) and As(V) at near neutral pH condition. Its adsorption capacities on As(III) and As(V) were found to be no less than 127.4 mg/g and 83.2 mg/g, respectively. Its arsenic adsorption mechanism was found to follow the inner-sphere complex mechanism, and abundant hydroxyl groups on its surface played the major role in its superior arsenic adsorption performance. It could be easily separated from treated water bodies with magnetic separation, and could be easily regenerated and reused while maintaining a high arsenic removal efficiency. This novel superparamagnetic magnesium ferrite nanoadsorbent may offer a simple single step adsorption treatment option to remove arsenic contamination from water without the pre-/post-treatment requirement for current industrial practice.

We focused on the surface microstructure and morphology changes of Cu/eutectic SnBi/Cu joint during solid-state aging process through ex situ scanning electron microscopy (SEM) observations and energy dispersive X-ray spectroscopy (EDXS) analysis. Different intermetallic compound (IMC) growth behaviors on the surface from the bulk of solder joints were observed and investigated. The results indicated that at the initial stage of solid-state aging IMCs protruded from the interfacial region with two different microstructures, the small particles on the Cu surface and chunk-type IMC at the solder side. With the increment of solid-state aging time, although the total thickness of IMCs increased very slowly, Cu3Sn phases grew fast by the consumption of Cu6Sn5 phase. Growth kinetic analyses for IMC on the surface and in the bulk of solder joints revealed that the IMC growth on the surface was faster than that in the bulk at the initial stage. For the long-term aging, although the total IMC thickness was still thicker than that in the bulk, the rate of the IMC growth on the surface was slower than that in the bulk. The growth of IMC on the surface of interfacial region was divided into two distinct stages, which corresponds to different IMC growth behaviors.

Titanium dioxide has been used for environmental applications. However, pure TiO2 has low photocatalytic efficiency outdoors because of its large energy band gap. Higher nitrogen-doping level would have lower band-gap energy and it would make it possible to improve the utilization ratio of solar energy. Heavily nitrogen-doped TiO2 could be obtained by using ion beam assisted deposition (IBAD) technique. Acceleration voltage is a very important parameter of IBAD technique and will affect the processes of depositing thin film. Under the given experiment condition, acceleration voltage had little effect on the structure and absorbance spectra of the obtained nitrogen-doped titanium oxide thin films, but had great effect on the deposition rate, composition and surface morphology of the thin films. When the accelerate voltage was 250V, the deposition rate was the highest (about 9.0 nm/min), the resulting TiO2-xNx films contained nitrogen levels up to x =0.45, the structures were mostly crystalline anatase and the amount of shift was observed about 500 nm. The optimum acceleration voltage is about 250V under the given condition.

Well-dispersed hollow TiO2 spheres were synthesized via Ostwald ripening through a fluorine-free solvothermal process in a n-PrOH/H2O mixed solvent. Several commonly used acids, such as HNO3, HCl, and H2SO4, were found to be effective as the ripening-directing agent to replace the highly corrosive HF, and the hollow TiO2 sphere size could be modulated by varying the reactant concentrations. The effects of the solvents and reactants were explored in details, which demonstrated that four important criteria existed in this fluorine-free process to create well-dispersed hollow TiO2 spheres, including the utilization of n-PrOH/H2O mixed solvent, certain degree of acidity, coexistence of different acids, and the existence of SO42− in the reaction solution. After calcination for a better crystallization, these hollow TiO2 spheres were composed of pure anatase phase, and had a good photocatalytic degradation performance on RhB under UV illumination.

The effects of exposure time, temperature and humidity on the growth of tin whisker and hillock from Sn5Nd alloy were investigated via scanning electron microscopy. It was found that tin whiskers grew from NdSn 3 compound, while hillocks grew from the tin matrix around the NdSn 3 compound, which was induced by the oxidation of NdSn 3 compound by oxygen and water vapor in the ambient. More tin whiskers and/or hillocks were extruded from the substrate with longer exposure time, higher temperature and higher humidity. This resulted in the formation of various morphologies of tin extrusions at different storage conditions, including thread-like, spiral, flute-like, claw-like, sprout-like, chrysanthemum-like and rod-like whiskers, as well as hillocks. Tin whisker was extruded from the crack of the surface Nd(OH) 3 layer which serves as the mold of tin whisker growth. And the proposed growth models of tin whisker and hillock on Sn–Nd alloy can explain the diversity of the whisker morphology.

Because Fe has a more negative standard reduction potential than Ni, the simultaneous electroless deposition of Fe and Ni is difficult. In this study, Fe–42Ni(P) electroless deposit was prepared by using disodium ethylene diamine tetraacetate (ETDA-2Na) as complexing agent to reduce the difference in the electrode potential between Ni 2+ and Fe 2+ . The solderability and the interfacial reaction between Fe−42Ni(P) alloy and Sn were investigated. It was found that the electroless Fe−42Ni(P) alloy has excellent wettability with Sn. Moreover, the interfacial reaction rate between Fe−42Ni(P) and Sn is very slow. These results suggest that Fe–42Ni(P) alloy may become an attractive under-bump metallization (UBM).

Ultrafine superparamagnetic magnesium ferrite nanocrystallites were successfully synthesized by doping Mg2+ into α-Fe2O3 in a solvent thermal process. The dopant altered the microstructure of the α-Fe2O3 which resulted in an enhanced arsenic adsorption performance and an easy magnetic separation capability. At a concentration of 10%, Mg-doping largely increased the surface area to ∼438 m2 g−1, enhanced the dispersion and contact with arsenic species in water due to its superparamagnetic behavior, and largely improved the arsenic adsorption performance in both lab-prepared and natural water samples at near neutral pH when compared with ultrafine α-Fe2O3 nanoparticles. At an Mg concentration of 10%, the amounts of As(III) and As(V) adsorbed reached 9.3 mg g−1 and 10 mg g−1, respectively, at a low equilibrium arsenic concentration of less than 10 μg L−1. The nanocrystallites could be easily separated from water when an external magnetic field was present after water treatment due to their high saturation magnetization, which solved the potential nanomaterial dispersion problem and facilitated arsenic desorption and reuse of the material.

The simultaneous electroless-deposition of Fe and Ni is challenging because Fe has a more negative standard reduction potential than Ni. In this study, FeNiP electroless deposits with Fe content up to 97 at.% were prepared by complexing with disodium ethylene diamine tetraacetate (EDTA-2Na). The addition of ETDA-2Na complexing agent effectively reduced the difference in the electrode potential between Ni and Fe from 0.21 V to 0.156 V, resulting in Fe-Ni depositions with very high Fe concentrations. The iron concentrations of deposited films were systematically investigated as functions of bath temperature, concentrations of EDTA-2Na and DTPA, mole ratio of Fe2+/Ni2+ and contents of NH3 center dot H2O in the plating bath. The solderability of electroless FeNiP deposits with Sn and SnAgCu solders was found to increase with the iron content in the deposits from 0 at.% to 85 at.%, and to be better than that of the electroless NiP. (C) 2013 The Electrochemical Society. All rights reserved.

Most photocatalysts only function under illumination, while many potential applications require continuous activities in dark. Thus, novel photocatalysts should be developed, which could store part of their photoactivity in “memory” under illumination and then be active from this “memory” after the illumination is turned off for an extended period of time. Here a novel composite photocatalyst of SnO2 nanoparticle-decorated Cu2O nanocubes is developed. Their large conduction band potential difference and the inner electrostatic field formed in the p-n heterojunction provide a strong driving force for photogenerated electrons to move from Cu2O to SnO2 under visible light illumination, which could then be released to react with O2 in dark to produce H2O2 for its post-illumination activity. This work demonstrates that the selection of decoration components for photocatalysts with the post-illumination photocatalytic “memory” could be largely expanded to semiconductors with conduction band potentials less positive than the two-electron reduction potential of O2.

Well crystallized niobium-doped TiO2 nanotube arrays (TiNbO-NT) were successfully synthesized via the anodization of titanium/niobium alloy sheets, followed with a heat treatment at 550 degrees C for 2 h. Morphology analysis results demonstrated that both the titanium/niobium alloy microstructure and the dissolution strength of electrolyte played major roles in the formation of nanotube structure. A single-phase microstructure was more favorable to the formation of uniform nanotube arrays, while modulating the dissolution strength of electrolyte was required to obtain nanotube arrays from the alloys with multi-phase microstructures. X-ray diffraction (XRD) and X-ray photoelectron (XPS) analysis results clearly demonstrated that niobium dopants (Nb5+) were successfully doped into TiO2 anatase lattice by substituting Ti4+ in this approach.