Search

Synthesizing nanopores which mimic the functionality of ion-selective biological channels has been a challenging yet promising approach to advance technologies for precise ion-ion separations. Inspired by the facilitated fluoride (F-) permeation in the biological fluoride channel, we designed a highly fluoride-selective TiO2 film using the atomic layer deposition (ALD) technique. The subnanometer voids within the fabricated TiO2 film (4 A < d < 12 A, with two distinct peaks at 5.5 and 6.5 A), created by the hindered diffusion of ALD precursors (d = 7 A), resulted in more than eight times faster permeation of sodium fluoride compared to other sodium halides. We show that the specific Ti-F interactions compensate for the energy penalty of F- dehydration during the partitioning of F- ions into the pore and allow for an intrapore accumulation of F- ions. Concomitantly, the accumulation of F- ions on the pore walls also enhances the transport of sodium (Na+) cations due to electrostatic interactions. Molecular dynamics simulations probing the ion concentration and mobility within the TiO2 pore further support our proposed mechanisms for the selective F- transport and enhanced Na+ permeation in the TiO2 film. Overall, our work provides insights toward the design of ion-selective nanopores using the ALD technique.

(Tb0.5Y0.5)2O3 transparent ceramics have been prepared by wet chemical co-precipitation route and flowing H2 atmosphere sintering. The optical quality, microstructure and magneto-optical properties of the ceramics were investigated. No sintering aids or milling were adopted in the ceramic fabrication processing. The cold isostatic pressed green compact could be sintered to be transparent (Tb0.5Y0.5)2O3 ceramic at 1800 ℃ in flowing H2 atmosphere. The mechanical polished ceramic showed the good transmittance from visible to near infrared wavelength, corresponding to a 71.9% transmittance at 1400 nm wavelength. The Verdet constant measured at 632.8 nm of the (Tb0.5Y0.5)2O3 transparent ceramics was -220.19 rad T−1 m-1, which was 1.64 times that of Tb3Ga5O12 single crystal.

Semiconductors of narrow bandgaps and high quantum efficiency have not been broadly utilized for photocatalytic coevolution of H(2) and O(2) via water splitting. One prominent issue is to develop effective protection strategies, which not only mitigate photocorrosion in an aqueous environment but also facilitate charge separation. Achieving local charge separation is especially challenging when these reductive and oxidative sites are placed only nanometers apart compared to two macroscopically separated electrodes in a photoelectrochemical cell. Additionally, the driving force of charge separation, namely the energetic difference in the barrier heights across the two type of sites, is small. Herein, we used conformal coatings attached by nanoscale cocatalysts to transform two classes of tunable bandgap semiconductors, i.e., CdS and GaInP(2), into stable and efficient photocatalysts. We used hydrogen evolution and redox-mediator oxidation for model study, and further constructed a two-compartment solar fuel generator that separated stoichiometric H(2) and O(2) products. Distinct from the single charge-transfer direction reported for conventional protective coatings, the coating herein allows for concurrent injection of photoexcited electrons and holes through the coating. The energetic difference between reductive and oxidative catalytic sites was regulated by selectivity and local kinetics. Accordingly, the charge separation behavior was validated using numerical simulations. Following this design principle, the CdS/TiO(2)/Rh@CrO(x) photocatalysts evolved H(2) while oxidizing reversible polysulfide redox mediators at a maximum rate of 90.6 μmol⋅h(−1)⋅cm(−2) by stacking three panels. Powered by a solar cell, the redox-mediated solar water-splitting reactor regenerated the polysulfide repeatedly and achieved solar-to-hydrogen efficiency of 1.7%.

Semiconductors of narrow bandgaps and high quantum efficiency have not been successfully utilised for coevolving photocatalysis despite the widely demonstrated protective coating schemes. Herein, we showcase a general strategy of using conformal coatings and cocatalysts energetic properties to transform CdS powders and GaInP2 films into stable and efficient photocatalysts for coevolution of H2 and reversible redox couples. A scalable redox-mediated solar water-splitting reactor was constructed, regenerating the redox mediators while evolving O2 in a separate compartment. Distinct from the single direction of charge transfer found with conventional photoelectrode stabilisation, the coating herein allows both photo-excited electrons and holes to spatially separate and inject simultaneously to the respective reductive and oxidative sites. With TiO2 stabilisation, CdS particles produced H2 continuously for 150 hours. Under simulated sunlight, solar-to-hydrogen (STH) efficiency of 5.9% and 9.4% can be achieved for the CdS and GaInP2 panels, respectively, by stacking multiple panels and matching the rate of redox regeneration to that of H2 production.

To study a new type of paper plastic film laminating product based on PVP and PVA and its related properties. L9 (33) orthogonal test was used to prepare PVP adhesives, in which three factors (levels) were PVP (10, 12, 14%), potassium stearate (1, 2, 3%) and glycerol concentration (8, 10, 12%). With the peel strength of PVP and PVA laminating products as the evaluation index, the optimal amount of PVP adhesive raw materials could be obtained. At the same time, the solid content and infrared spectrum of the adhesive and the thermal shrinkage rate of the laminating product were measured. The optimal amount of PVP adhesive for laminating was: 10% for PVP, 3% for potassium stearate and 12% for glycerin. The solid content of 10, 12, and 14% PVP adhesives were 55, 67 and 75%, respectively, satisfying the requirements for adhesives for laminating. Infrared spectroscopy analysis showed that there were interactions between the PVP molecules and glycerol hydrogen bonds, and the addition of potassium stearate and glycerin improved the performance of the PVP adhesive and enhanced its stability. With being tested by constant temperature and humidity and heat shrinkage, the samples showed no separation, shrinkage, blistering, wrinkling, warping and discoloration, and had excellent stability. In this paper, the optimum raw material dosage of PVP adhesive for laminating was obtained, and paper plastic laminatings based on PVP adhesive and PVA film were prepared.

Ytterbium doped Lu1.5Y1.5Al5O12 (LuYAG) nanocrystalline powders were synthesized by a wet chemical mixed precipitant co-precipitation (MPP) method, and then the mixed crystal of Yb:LuYAG was grown in an optical floating zone (OFZ) furnace at the speed of 6&ndash, 10 mm/h, using a [111] oriented YAG seed crystal. The transmittance of the polished LuYAG crystal is close to the ideal value of LuAG or YAG. The X-ray rocking curve shows complete symmetry and the full width at half maximum (FWHM) is 10 arc-second, indicating the good quality of as grown Yb:LuYAG multicomponent garnet crystal. The thermal luminescent spectrum at room temperature shows four deep energy traps at around 1&ndash, 1.3 eV. X-ray excited luminesce (XEL) spectra is measured to characterize the existence of LuAl or YAl shadow defects in the bulk single crystal. The emission peak at around 320 nm indicates that the LuYAG crystal prepared by OFZ have lower concentrations of antisite defects (AD) with respect to its Czochralski counterpart.

Most of current packaging tape are made of non-degradable BOPP film, subsequently rendering carton recycled lose commercial value and causing a great hazard on the living environment. PVA film is known as a type of environmentally friendly material because of its excellent characteristics, e.g. water solubility and degradability. Since PVA film has strong polarity, it is necessary to coat surfactants to reduce the surface tension. In the paper, Span20, Span60, Span80 and Tween60 were coated on the other side of PVA hot-melt adhesive tape by hand. The surface tension was measured under different placement time. It measured the 180° peel strength of PVA hot-melt adhesive tape coated with surfactants in comparison to PVA hot-melt adhesive tape without surfactants and BOPP tape so that appropriate surfactants were chosen. The results show that the surfactants can reduce surface tension of the other side of PVA hot-melt adhesive tape. However, only the mass ratio of Span60 and C2H6O is between 1:5 and 1:10, the 180° peel strength of PVA hot-melt adhesive tape is the best. PVA hot-melt adhesive tape with other surfactants is stuck together when the tape is crimped or its peel strength is too small.