透明水泥i.light

意大利水泥集团(Italcementi)的建筑师们把特殊树脂与一种新混合物结合在一起,制成透明水泥.采用这种水泥建成的建筑物,整面墙就像个巨大的窗户,阳光能穿透墙体射进室内,这样就可减少室内灯光使用量,从而节省能源. 透明水泥i.light的里面有很多小孔,这些小孔可在不破坏建筑物结构的整体性的前提下,令阳光投射进来.     

Photocatalytic effects of plasma-heated TiO2−x particles under visible light irradiation

The photocatalytic characteristics of partially reduced TiO₂ (TiO_2?x ) by plasma treatment and plasma-heated treatment were investigated in the visible-light region. For the visible-light photocatalytic activity of TiO_2?x , plasmaheated treatment shows stronger than plasma treatment significantly. The TiO_2?x by plasma-heated treatment shows broader red-shifted absorption bands than one by plasma treatment in the visible-light region. The surface color of TiO_2?x by plasma treatment and plasma-heated treatment changed from white to sky blue, and to navy, respectively. After exposure to air, the surface color of TiO_2?x changed from sky blue to white for plasma treatment and from navy to beige for plasma-heated treatment.     

Development and evaluation of Al2O3–ZrO2 composite processed by digital light 3D printing

Digital Light Processing (DLP) is a promising approach to fabricate delicate ceramic components with high-fidelity structural features. In this work, the alumina and zirconia/alumina ceramic suspensions with low viscosity and high solid loading (40 vol%) were prepared specifically for DLP 3D printing. After debinding and sintering, the final parts were obtained without any defects. The surface morphologies and mechanical properties of alumina (Al₂O₃) and zirconia toughened alumina (ZTA) composites were investigated and the results showed that the final parts exhibited high relative densities and good interlayer combination at the sintering temperature of 1600 °C. Comparing with the Al₂O₃, the ZTA composites exhibited significantly enhanced density (99.4%), bending strength (516.7 MPa) and indentation fracture toughness (7.76 MPa m^1/2).     

Doping and luminescence mechanisms of broadband NIR-II emitting Zn2(1−x)Ni2xGa3Ge0.75O8 nanoparticles

In this study, Zn_2(1−x)Ni_2xGa₃Ge_0.75O₈ (x = 0.0002, 0.001, 0.002, 0.010, 0.020, and 0.030) nanoparticles with broadband NIR-II emissions were synthesized by a hydrothermal synthesis combined with a vacuum annealing. For the Ni²⁺-doped ZGGO samples (x = 0–0.03), with increasing concentration, the particle shape gradually becomes spherical and the average particle size decreases from 124.4 to 74.2 nm. Meanwhile, for the ZGGO:Ni²⁺_0.01 nanoparticles, the asymmetrically broad emission peak around 1290 nm, which is the superposition of the two peaks locating at 1280 and 1450 nm, can be observed and the afterglow time exceeds 30 min. Based on the spectral data, luminescence decay curves, first-principles calculations, and Tanabe–Sugano theory, it is found that Ni²⁺ ions can occupy not only tetrahedral but also octahedral Zn²⁺ sites (locating in anti-site defects pair) in the spinel ZGGO host, and they have the contributions to the 1450 and 1280 nm emission peaks, respectively. Furthermore, the surface-modified ZGGO:Ni²⁺ nanoparticles exhibited good stability in the H₂O and HSA (5% human serum albumin, pH = 7.4) solutions and the occurred agglomeration sinking in the SLS (simulate lysosomal solution, pH = 4.7) solution. Compared to the narrow-band NIR-II emitting persistent luminescence nanoparticles (ZGGO:Cr³⁺,Er³⁺ and ZGGO:Cr³⁺,Nd³⁺), broadband NIR-II emitting persistent luminescence nanoparticles (ZGGO:Ni²⁺ NIR-II) possess stronger persistent luminescence intensity and can effectively avoid the water absorption of biological tissues. Our results suggest that ZGGO:Ni²⁺ persistent luminescence nanoparticles have a potential to become optical probes for deep-tissue autofluorescence-free bioimaging in the biomedical field.     

UV-curable polyurethane acrylate–Ag/TiO2 nanocomposites with superior UV light antibacterial activity

Polyurethane acrylate (PUA)–Ag/TiO₂ nanocomposites were synthesized through in situ polymerization. The well-dispersed Ag/TiO₂ nanorods serve as photoinitiator. Meanwhile, the PUA–Ag/TiO₂ nanocomposite films exhibit superior activity toward the photocatalytic degradation of Escherichia coli under UV light. The excellent UV curing and antibacterial activities can be ascribed to the synergistic effect of Ag and TiO₂, which promotes the effective electron/hole separation and thus generates various reactive species. Thin films with these nanoparticles are more hydrophilic after UV illumination. And the antibacterial mechanism of the UV-curable PUA–Ag/TiO₂ nanocomposites was proposed.     

Novel Mn4+ doped Ca2GdSbO6 red–emitting phosphor: A potential color converter for light-emitting diodes

As potential color converter towards white/red light–emitting diodes, novel Ca₂GdSbO₆:Mn⁴⁺ phosphors with excellent optical performances were prepared by a conventional solid–state reaction route. The as–prepared phosphors with monoclinic crystal system had abundant [SbO₆] octahedrons for Mn⁴⁺ ions to occupy and stably exist. With an excitation of 356 nm, an intense red emission peaking at 676 nm attributed to ²E_g→⁴A_2g transition of Mn⁴⁺ ions can be observed in the emission spectrum. The critical concentration of Mn⁴⁺ ions was found to be 0.6 mol% and the concentration quenching mechanism was also discussed in detail. Importantly, the Ca₂GdSbO₆:0.6%Mn⁴⁺ phosphors exhibited a high internal quantum efficiency of 38.9%.     

Microwave-assisted synthesis of Ag–TiO2/graphene composite for hydrogen production under visible light irradiation

Novel photocatalysts based on silver (Ag), TiO₂, and graphene were successfully synthesized by microwave-assisted hydrothermal method. The prepared photocatalysts were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) specific surface area analysis, X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS). The influence of silver loading and graphene incorporation on photocatalytic hydrogen (H₂) production of as-prepared samples was investigated in methanolic aqueous solution under visible light irradiation (λ≥420 nm). The results showed that Ag–TiO₂/graphene composite had appreciably enhanced photocatalytic H₂ production performance under visible light illumination compared to pure TiO₂, Ag–TiO₂ and TiO₂/graphene samples. The enhanced photocatalytic hydrogen production activity of Ag–TiO₂/graphene composite under visible light irradiation could be attributed to increased visible light absorption, reduced recombination of photogenerated charge carriers and high specific surface area. This novel study provides more insight for the development of novel visible light responsive TiO²⁻ graphene based photocatalysts for energy applications.     

Photocatalytic behavior of TiO_2 and ZnO prepared with different methods under ultraviolet and visible light irradiation

IntroductionIn recent years photocatalytic oxidation hasreceived considerable attention as an alternativeremediation technology since the method offers anumber of advantages over conventionaltechnologies [1,2] Elimination o…     

Visible light assisted highly efficient hydrogen production from H2S decomposition by CuGaO2 and CuGa1−xInxO2 delafossite oxides bearing nanostructured co-catalysts

The present communication is the report of our research work on synthesis of new delafossite oxides containing Ga/Ga and In p-block elements, and their visible light driven catalytic activity in solar H₂ production from H₂S decomposition. CuGaO₂ and its indium doped analogue CuGa_1−xIn_xO₂ (x = 0.065) delafossite oxides without/with NiO and RuO₂ co-catalysts loading in nanostructures were prepared by solid state reaction method. These materials possess hexagonal rhombohedral structure (XRD); morphologically CuGaO₂ has irregularly-shaped plate like particles while all others have ordered hexagonal rod-like arrangements (FESEM). Co-catalyst deposits of few nm sizes are observable as white spots/patches on the surface of naked oxide catalysts. Acquiring p-type conductivity from the mixed valence of Cu (+1 and +2) and oxygen deficiency, these catalysts strongly absorb visible light (Eg = 1.85 eV) in a wide wavelength range. They decompose H₂S in aqueous 0.5 M KOH solution under visible light (λ ⩾ 420 nm) irradiation and generate H₂ to the tune of 4300 μmol/h, giving rise to a high quantum efficiency of 13.6% at 550 nm. The exceedingly higher rate of H₂ production appears to result from a combined contribution of chemical nature (p-block elements Ga and In), p-type conductivity and an efficient e⁻–h⁺ separation.     

High-performance Al2O3‒YAG:Ce composite ceramic phosphors for miniaturization of high-brightness white light-emitting diodes

The miniaturization of high-brightness white light-emitting diodes (WLEDs) is limited by the low thermal performance of phosphors. In this study, the microstructure, optical properties, and thermal performance of Al₂O₃–Y₃Al₅O₁₂:Ce³⁺ (Al₂O₃–YAG:Ce) composite ceramics fabricated by hot pressing were investigated. By promoting the growth of Al₂O₃ grains while maintaining a high composite density, thermal performance of the composite ceramics was significantly increased. The thermal conductivity of a Al₂O₃–40-vol% YAG:Ce ceramic reached 21.8 W/m/K, which is close to the theoretical value. In addition, this composite ceramic exhibited the highest energy efficiency. After packaging with a high-power LED chip with dimensions of 1 mm × 1 mm, a high luminous flux of 639 lm was generated, while the reduction in output power at 250 °C was as low as 6%. This indicated excellent high-temperature stability and potential for applications in solid-state lighting.     

Visible light photocatalytic degradation of thiophene using Ag–TiO2/multi-walled carbon nanotubes nanocomposite

Ag–TiO₂ nanocatalyst, supported on multi-walled carbon nanotubes, was synthesized successfully via a modified sol–gel method, and the prepared photocatalyst was used to remediate aqueous thiophene environmentally by photocatalytic oxidation under visible light. The prepared Ag–TiO₂/multi-walled carbon nanotubes nanocomposite photocatalyst was characterized through X-ray diffraction, Brunauer–Emmett–Teller (BET), transmission electron microscopy, and UV–vis spectra (UV–vis). The results showed that both Ag and TiO₂ nanoparticles were well-dispersed over the MWCNTs and formed a uniform nanocomposite. Ag doping can eliminate the recombination of electron–hole pairs in the catalyst, and the presence of MWCNTs in the TiO₂ composite can change surface properties to achieve sensitivity to visible light. The optimum mass ratio of MWCNT:TiO₂:Ag was 0.02:1.0:0.05, which resulted in the photocatalyst's experimental performance in oxidizing about 100% of the thiophene in a 600 mg/L solution within 30 min and with 1.4 g L⁻¹ amount of catalyst used.     

Degradation of phenol in industrial wastewater over the F–Fe/TiO_2 photocatalysts under visible light illumination

F–Fe/TiO_2 composite photocatalyst was synthesized by a facile one-step hydrothermal method and then characterized by XRD, XPS and UV–Vis DRS. The catalyst of F–Fe/TiO_2 exhibited the highest photodegradation rate for phenol as compared with pure TiO_2, F/TiO_2, Fe/TiO_2, F0.38–Fe0.13–TiO_2 and Fe(III)/F-TiO_2 under visible light irradiation. The simulated conditions of industrial phenolic wastewater including initial phenol concentration,visible light intensity, p H and different anions were investigated in the presence of F–Fe/TiO_2 photocatalyst. In addition, as expected, the F–Fe/TiO_2 photocatalyst displayed excellent stability, showing a potential industrial application for the treatment of phenolic wastewater.     

Catalytic activity of mesoporous TiO2−xNx photocatalysts for the decomposition of methyl orange under solar simulated light

Using Tween 80 as pore-directing agent, mesoporous TiO_2?xN_x was prepared via the hydrolysis of TTIP (titanium tetraisopropoxide) in a mixed aqueous solution of isopropanol and acetic acid in the presence of urea. The resulting mesoporous TiO_2?xN_x was characterized by XRD, N₂ adsorption–desorption isotherms, TEM, UV–vis diffuse reflectance spectra and EDS. TEM and N₂ adsorption–desorption isotherms showed that the TiO_2?xN_x has a uniform mesoporous structure. UV–vis spectra revealed that the nitrogen doping caused the absorption edge of TiO_2?xN_x to shift to the visible region. 10%N–TiO₂ exhibited the highest photocatalytic activity for degradation of MO aqueous solution under solar simulated light irradiation.     

Blue and red light photoluminescence emission at room temperature from CaTiO3 decorated with α-Ag2WO4

CaTiO₃ (CT) and α-Ag₂WO₄ (AW) semiconductors are widely known for their interesting electrical and photoluminescence (PL) properties. In this study, we decorated CT with AW for obtaining CaTiO₃:α-Ag₂WO₄ (CT:AW), and investigated the properties of the produced materials, especially their PL properties. The X-ray diffraction peaks of the synthesized microcrystals were well indexed to the orthorhombic phase for all the samples. Two morphologies: cube-like for CT and rod-like for AW were observed by field-emission scanning electron microscopy (FE-SEM). The FE-SEM and transmission electron microscopy (TEM) studies indicated the presence of rod-shaped AW deposited on the surfaces of cube-shaped CT morphology. PL emission of the decorated samples overlaps all the visible region spectra because of the contribution from both the constituent materials that induce maximum emissions in the blue and red regions. The examination of Commission internationale de ĺéclairage (CIE) coordinates confirmed that the decorated samples exhibit favored emission the red wavelength region.     

Preparation of oriented SiO32− doped TiO2 film and degradation of methylene blue under visible light irradiation

SiO₃^2? doped TiO₂ films with oriented nanoneedle and nanorectangle block structure has been firstly synthesized by hydrothermal synthesis method. The prepared samples are characterized, X-ray diffraction (XRD) results demonstrate that the SiO₃^2? doped TiO₂ films are rutile and brookite phases. The scanning electron microscope (SEM) analysis reveals that the quantity of O₂ affects the morphology of the SiO₃^2? doped TiO₂ films (SiTiA films prepared with unmodified substrate). The SiO₃^2? doped TiO₂ films (SiTiB films prepared with modified substrate) display two layers, one is porous structure, the other is nanoneedle structure. UV–vis, IR, transmission electron microscopy (TEM) and energy-dispersive X-ray (EDX) microscopy all prove that SiO₃^2? have been doped in the TiO₂ crystal structure. They have remarkable red shift and higher photocatalytic activity of degradation of methylene blue than P-25 under visible light (λ > 420 nm) irradiation. Besides, photocatalytic activity of the film is stable during 4 times recycling.     

Microwave dielectric properties of (0.75ZnAl2O4–0.25TiO2)–MgTiO3 ceramics prepared using digital light processing technology

ZTM ceramics comprising of 0.75ZnAl₂O₄–0.25TiO₂ and MgTiO₃ at a ratio of 90:10 wt.% are widely used in the field of communication as filters and resonators owing to their excellent microwave dielectric properties. However, the development of such dielectrics with complex structures, as required by microwave devices, is difficult using traditional fabrication methods. In this study, ZTM microwave dielectric ceramics were prepared using the digital light processing (DLP) technology. The influence of the sintering temperature on the phase composition, microstructure, and microwave dielectric properties of ZTM ceramics was investigated. Results showed that with an increase in the sintering temperature, the dielectric constant (ε_r) and quality factor (Q × f) of ZTM ceramics initially increased owing to the increase in the density and diffusion of ions. However, when the sintering temperature was excessively high, the abnormal growth of crystal grains and micropores led to a decrease in ε_r and Q × f. The ZTM ceramics sintered at 1450°C exhibited the optimum microwave dielectric properties (ε_r = 12.99, Q × f = 69 245 GHz, τ_f = −9.50 ppm/°C) owing to the uniform microstructure and a high relative density of 95.02%. These results indicate that DLP is a promising method for preparing high-performance microwave dielectric ceramics with complex structures.     

Preparation of cobalt coated TiO2 and WO3–TiO2 nanotube films via photo-assisted deposition with enhanced photocatalytic activity under visible light illumination

Highly ordered TiO₂ and WO₃–TiO₂ nanotubes were prepared by one-step electrochemical anodizing method and cobalt has been successfully deposited on these nanotubes by photo-assisted deposition process. The morphology, crystal structure, elemental composition and light absorption capability of samples were characterized by field emission scanning electron microscope, X-ray diffraction, energy dispersive X-ray spectrometer and ultraviolet–visible spectroscopy methods. All cobalt loaded samples show an appearance of red shift relative to the unloaded samples. The degradation of methylene blue was used as a model reaction to evaluate the photocatalytic activity of these novel visible-light-responsive photocatalysts. Results showed that the photocatalytic activity of bare WO₃–TiO₂ samples is higher than that with undoped TiO₂ sample. Compared with unmodified TiO₂ and WO₃–TiO₂, the Co/TiO₂ and Co/WO₃–TiO₂ samples exhibited enhanced photocatalytic activity in the degradation of methylene blue. Kinetic research showed that the reaction rate constant of Co/WO₃–TiO₂ is approximately 2.26 times higher than the apparent reaction rate constant of bare WO₃–TiO₂. This work provides an insight into designing and synthesizing new TiO₂–WO₃ nanotubes-based hybrid materials for effective visible light-activated photocatalysis. The catalysts prepared in this study exhibit industrially relevant interests due to the low cost and high photocatalytic activity.