A magnetized nano‐photocatalyst based on TiO2/magnetic graphene was developed for efficient photodegradation of crystal violet (CV). Scanning electron microscopy, X‐ray diffraction, energy‐dispersive X‐ray spectroscopy and elemental mapping were used to characterize the prepared magnetic nano‐photocatalyst. The photocatalytic activity of the synthesized magnetic nano‐photocatalyst was evaluated using the decomposition of CV as a model organic pollutant under UV light irradiation. The obtained results showed that TiO2/magnetic graphene exhibited much higher photocatalytic performance than bare TiO2. Incorporation of graphene enhanced the activity of the prepared magnetic nano‐photocatalyst. TiO2/magnetic graphene can be easily separated from an aqueous solution by applying an external magnetic field. Effects of pH, magnetized nano‐photocatalyst dosage, UV light irradiation time, H2O2 amount and initial concentration of dye on the photodegradation efficiency were evaluated and optimized. Efficient photodegradation (>98%) of the selected dye under optimized conditions using the synthesized nano‐photocatalyst under UV light irradiation was achieved in 25 min. The prepared magnetic nano‐photocatalyst can be used in a wide pH range (4–10) for degradation of CV. The effects of scavengers, namely methanol (OH? scavenger), p‐benzoquinone (O2?? scavenger) and disodium ethylenediaminetetraacetate (hole scavenger), on CV photodegradation were investigated. 相似文献
Tungsten trioxide‐poly(3,4‐ethylenedioxythiophene) (WO3‐PEDOT) and tungsten trioxide‐polyfuran (WO3‐PFu) were prepared by rf rotating plasma polymerization. Electrochromic hybrid thin films were fabricated onto flexible polyethylene terephthalate (PET)/ indium tin oxide (ITO) film using electron beam evaporation method. In order to deeply characterize all films, scanning electron microscopy‐energy dispersive X‐ray spectroscopy (SEM‐EDS) and electrochemical impedance spectroscopy (EIS) techniques were used. The counter electrode effect on plasma modified WO3 nano hybrids‐based electrochromic devices (ECDs) was evaluated. By incorporating flexible vanadium pentoxide (V2O5) film as counter electrode, complementary ECDs were constructed through combining the hybrid flexible films (WO3‐PEDOT, WO3‐PFu) as working electrodes, which exhibit highly efficient electrochromic performance with low voltage operation. Especially, WO3‐PEDOT/V2O5‐based ECD owns a high optical modulation of 61.5 % at 750 nm driven by −1.0 V (coloration) and +1 V (bleaching) with fast response times (coloration time: 13.58 s, bleaching time: 8.07 s) and a high coloration efficiency of 527 cm2 C−1. This study can supply useful and efficient avenue for designing flexible complementary electrochromic device for energy‐saving flexible electronics. 相似文献
The photocatalytic activity of TiO2 nanoparticles (nano‐TiO2) and its hybrid with SiO2 (nano‐TiO2–SiO2) for degradation of some organic dyes on cementitious materials was studied in this work. Nanohybrid photocatalysts were prepared using an inorganic sol–gel precursor and then characterized using XRD, SEM and UV–Vis. The grain sizes were estimated by Scherrer's equation to be around 10 nm. Then, a thin layer was applied to Portland cement concrete (PCC) blocks by dipping them into nano‐TiO2 and nano‐TiO2–SiO2 solution. The efficiency of coated PCC blocks for the photocatalytic decomposition of two dyes, Malachite Green oxalate (MG) and Methylene Blue (MB), was examined under UV and visible irradiation and then monitored by the chemical oxygen demand tests. The results showed that more than 80% and 92% of MG and MB were decomposed under UV–Vis irradiation using blocks coated with nano‐TiO2–SiO2. TiO2/PCC and TiO2–SiO2/PCC blocks showed a significant ability to oxidize dyes under visible and UV lights and TiO2–SiO2/PCC blocks require less time for dye degradation. Based on these results, coated blocks have increased photocatalytic activity which can make them commercially accessible photocatalysts. 相似文献
A facile way of controlling the structure of TiO2 by changing the amount of water to improve the efficiency of dye‐sensitized solar cells (DSSCs) is reported. Hierarchically ordered TiO2 films with high porosity and good interconnectivity are synthesized in a well‐defined morphological confinement arising from a one‐step self‐assembly of preformed TiO2 (pre‐TiO2) nanocrystals and a graft copolymer, namely poly(vinyl chloride)‐g‐poly(oxyethylene methacrylate). The polymer–solvent interactions in solution, which are tuned by the amount of water, are shown to be a decisive factor in determining TiO2 morphology and device performance. Systematic control of wall and pore size is achieved and enables the bifunctionality of excellent light scattering properties and easy electron transport through the film. These properties are characterized by reflectance spectroscopy, incident photon‐to‐electron conversion efficiency, and electrochemical impedance spectroscopy analyses. The TiO2 photoanode that is prepared with a higher water ratio, [pre‐TiO2]:[H2O]=1:0.3, shows a larger surface area, greater light scattering, and better electron transport, which result in a high efficiency (7.7 %) DSSC with a solid polymerized ionic liquid. This efficiency is much greater than that of commercially available TiO2 paste (4.0 %). 相似文献
Anatase TiO2 nanorods with large specific surface areas and high crystallinity have been synthesized by surfactant‐free hydrothermal treatment of water‐soluble peroxotitanium acid (PTA). X‐ray diffraction and TEM analysis showed that all TiO2 nanorods derived from PTA in different hydrothermal processes were in the anatase phase, and high aspect ratio TiO2 nanorods with chain‐shaped structures were formed at 150 °C for 24 h by oriented growth. The nanorods were fabricated as photoanodes for high‐efficiency dye‐sensitized solar cells (DSSCs). DSSCs fabricated from the chain‐shaped TiO2 nanorods gave a highest short‐circuit current density of 14.8 mA cm?2 and a maximum energy conversion efficiency of 7.28 %, as a result of the presence of far fewer surface defects and grain boundaries than are present in commercial P25 TiO2 nanoparticles. Electrochemical impedance spectroscopy also confirmed that DSSCs based on the TiO2 nanorods have enhanced electron transport properties and a long electron lifetime. 相似文献
The shielding effect of nano TiO2 on collagen under UV radiation was investigated using UV spectrophotometry. The results indicate that the shielding of collagen under UV radiation in the presence of nano TiO2 is significant. For 2.5 wt.‐% of TiO2, there is a greater shielding effect of UV radiation than that for 0.5 wt.‐% of TiO2. In addition, this study gives hints that a novel tanning agent with a UV shielding function can be formulated by using nano TiO2.
UV absorption of collagen under UV radiation after adding 2.5 wt.‐% TiO2. 相似文献
Flower like structure TiO2 thin films have been grown onto ITO coated glass substrates by sol–gel method. TiO2 nano flowers have been sensitized using CdS quantum dots prepared using simple precursors by chemical method. The assembly
of CdS quantum dots with TiO2 nano flower has been used as photo-electrode in quantum dot sensitized solar cells. The surface morphology has been studied
using scanning electron microscope; it shows that the film exhibits flower like structure. The absorption spectra reveals
that the absorption edge of CdS quantum dot sensitized TiO2 nano flower shifts towards longer wavelength side when compared to the absorption edge of TiO2 nano flower. The efficiency of the fabricated CdS quantum dot sensitized TiO2 nano flower based solar cell is 0.66%. 相似文献
n ‐Butylsulfonated nano‐titania (n‐TiO2‐NH‐(CH2)4‐SO3H) as a highly efficient and reusable nanocatalyst was prepared by grafting 2,4‐toluene diisocyanate as a bi‐functional covalent linker onto a nano‐titania support, followed by reduction and then ring opening‐reaction of the synthesized amine with 1,4‐butanesultone. Fourier transform infrared spectroscopy, X‐ray diffraction, field‐emission scanning electron microscopy and thermogravimetric analysis were used to characterize the catalyst. The catalytic activity of n‐TiO2‐NH‐(CH2)4‐SO3H was evaluated in the synthesis of tetrahydrobenzo[b ]pyrans, which affords high yields. Statistical experimental design was applied as an efficient and powerful method to achieve the optimal conditions for this catalytic reaction leading to high yield. Moreover, the catalyst was recovered and reused at least six times without a significant decrease in catalytic activity. 相似文献
A unique one‐dimensional (1D) sandwich single‐walled TiO2 nanotube (STNT) is proposed as a photoanode nanomaterial with perfect morphology and large specific surface area. We have thoroughly examined the elementary photoelectronic processes occurring at the porphyrin dye/STNT hetero‐interface in dye‐sensitized solar cells (DSSCs) by theoretical simulation. It is desirable to investigate the interfacial photoelectronic processes to elucidate the electron transfer and transport mechanism in 1D STNT‐based DSSCs. We have found that the photoexcitation and interfacial charge separation mechanism can be described as follows. A ground‐state electron of the dye molecule (localized around the electron donor) is first promoted to the excited state (distributed electron donor), and then undergoes ultrafast injection into the conduction band of the STNT, leaving a hole around the oxidized dye. Significantly, the injected electron in the conduction band is transported along the STNT by means of Ti 3d orbitals, offering a unidirectional electron pathway toward the electrode for massive collection without the observation of trap states. Our study not only provides theoretical guidelines for the modification of TiO2 nanotubes as a photoanode material, but also opens a new perspective for the development of a novel class of TiO2 nanotubes with high power‐generation efficiency. 相似文献