This study reports the development of anatase TiO2 synthesized by facile photon-induced method (PIM) at various reaction times of 6 days, 8 days, 10-day samples. The 10 days TiO2 sample shows stable anatase phase, whereas 100% rutile phase at the same temperature was observed for standard TiO2. Mainly, the PIM was used to tuning the properties of visible light absorbance TiO2 photocatalyst used for improving antibacterial performance. The antibacterial activity of TiO2 against Staphylococcus aureus and Escherichia coli was determined by the agar disc diffusion method. Anatase TiO2 nanoparticles demonstrated excellent antibacterial activity against extracellular S. aureus with 80% and E. coli with 82% killing efficacy at concentrations as low as 100 μg/mL, which is 100% faster than the standard and other pure TiO2 reported earlier. The obtained undoped anatase Titania with enhanced chemical reactivity has great potential for antibacterial properties. Moreover, the smaller crystallite size (25 nm) and narrowing bandgap (2.96 eV) TiO2 nanoparticles were more effective in killing bacteria compared with standard TiO2. Therefore, this work indicated that anatase phased TiO2 under visible light absorbance has good potential with excellent clinical applications.
Hollow SiO2/TiO2 nanoparticles decorated with Ag nanoparticles (NPs) of controlled size (Ag@HNPs) were fabricated in order to enhance visible‐light absorption and improve light scattering in dye‐sensitized solar cells (DSSCs). They exhibited localized surface plasmon resonance (LSPR) and the LSPR effects were significantly influenced by the size of the Ag NPs. The absorption peak of the LSPR band dramatically increased with increasing Ag NP size. The LSPR of the large Ag NPs mainly increased the light absorption at short wavelengths, whereas the scattering from the SiO2/TiO2 HNPs improved the light absorption at long wavelengths. This enabled the working electrode to use the full solar spectrum. Furthermore, the SiO2 layer thickness was adjusted to maximize the LSPR from the Ag NPs and avoid corrosion of the Ag NPs by the electrolyte. Importantly, the power conversion efficiency (PCE) increased from 7.1 % with purely TiO2‐based DSSCs to 8.1 % with HNP‐based DSSCs, which is an approximately 12 % enhancement and can be attributed to greater light scattering. Furthermore, the PCEs of Ag@HNP‐based DSSCs were 11 % higher (8.1 vs. 9.0 %) than the bare‐HNP‐based DSSCs, which can be attributed to LSPR. Together, the PCE of Ag@HNP‐based DSSCs improved by a total of 27 %, from 7.1 to 9.0 %, due to these two effects. This comparative research will offer guidance in the design of multifunctional nanomaterials and the optimization of solar‐cell performance. 相似文献
Covalent triazine‐based frameworks (CTFs) with a graphene‐like layered morphology have been controllably synthesized by the trifluoromethanesulfonic acid‐catalyzed nitrile trimerization reactions at room temperature via selecting different monomers. Platinum nanoparticles are well dispersed in CTF‐T1, which is ascribed to the synergistic effects of the coordination of triazine moieties and the nanoscale confinement effect of CTFs. CTF‐T1 exhibits excellent photocatalytic activity and stability for H2 evolution in the presence of platinum under visible light irradiation (λ ≥ 420 nm). The activity and stability of CTF‐T1 are comparable to those of g‐C3N4. Importantly, as a result of the tailorable electronic and spatial structures of CTFs that can be achieved through the judicial selection of monomers, CTFs not only show great potential as organic semiconductor for photocatalysis but also may provide a molecular‐level understanding of the inherent heterogeneous photocatalysis.
Present work mainly focuses on experimental investigation to improvement of hydrogen production by water photoelectrolysis. An experimental facility was designed and constructed for visible light photocatalysis. A series of N‐TiO2 photocatalysts impregnated with platinum on the surface of N‐TiO2 were prepared. Hydrogen production upon irradiating aqueous Pt/N‐TiO2 suspension with visible light was investigated. The shift in excitation wavelength of TiO2 was 380 nm improved the yield of hydrogen production by N‐TiO2 and Pt/N‐TiO2. We used a 400 W mercury arc lamp combined with a 400 nm cutoff filter eliminating all the wavelengths under 400 nm. Pt/N‐TiO2 material was characterized with TPR, reflective UV/Visible spectroscopy and TEM. The best hydrogen production rate obtained for this setup for N/Ti = 10, 0.05 wt% Pt/N‐TiO2, through water splitting was about 772 μmolh?1g?1. 相似文献
P‐type Cu2O has been long considered as an attractive photocatalyst for photocatalytic water reduction, but few successful examples has been reported. Here, we report the synthesis of TiO2 (core)/Cu2O (ultrathin film shell) nanorods by a redox reaction between Cu2+ and in‐situ generated Ti3+ when Cu2+‐exchanged H‐titanate nanotubes are calcined in air. Owing to the strong TiO2‐Cu2O interfacial interaction, TiO2 (core)/Cu2O (ultrathin film shell) nanorods are highly active and stable in photocatalytic water reduction. The TiO2 core and Cu2O ultrathin film shell respectively act as the photosensitizer and cocatalyst, and both the photoexcited electrons in the conduction band and the holes in the valence band of TiO2 respectively transfer to the conduction band and valence band of the Cu2O ultrathin film shell. Our results unambiguously show that Cu2O itself can act as the highly active and stable cocatalyst for photocatalytic water reduction. 相似文献
The photocatalytic activity of graphite‐like carbon nitride (g‐C3N4) could be enhanced by heterojunction strategies through increasing the charge‐separation efficiency. As a surface‐based process, the heterogeneous photocatalytic process would become more efficient if a larger contact region existed in the heterojunction interface. In this work, ultrathin g‐C3N4 nanosheets (g‐C3N4‐NS) with much larger specific surface areas are employed instead of bulk g‐C3N4 (g‐C3N4‐B) to prepare AgIO3/g‐C3N4‐NS nanocomposite photocatalysts. By taking advantage of this feature, the as‐prepared composites exhibit remarkable performances for photocatalytic wastewater treatment under visible‐light irradiation. Notably, the optimum photocatalytic activity of AgIO3/g‐C3N4‐NS composites is almost 80.59 and 55.09 times higher than that of pure g‐C3N4‐B towards the degradation of rhodamine B and methyl orange pollutants, respectively. Finally, the stability and possible photocatalytic mechanism of the AgIO3/g‐C3N4‐NS system are also investigated. 相似文献
Copper is a low‐cost plasmonic metal. Efficient photocatalysts of copper nanoparticles on graphene support are successfully developed for controllably catalyzing the coupling reactions of aromatic nitro compounds to the corresponding azoxy or azo compounds under visible‐light irradiation. The coupling of nitrobenzene produces azoxybenzene with a yield of 90 % at 60 °C, but azobenzene with a yield of 96 % at 90 °C. When irradiated with natural sunlight (mean light intensity of 0.044 W cm−2) at about 35 °C, 70 % of the nitrobenzene is converted and 57 % of the product is azobenzene. The electrons of the copper nanoparticles gain the energy of the incident light through a localized surface plasmon resonance effect and photoexcitation of the bound electrons. The excited energetic electrons at the surface of the copper nanoparticles facilitate the cleavage of the N O bonds in the aromatic nitro compounds. Hence, the catalyzed coupling reaction can proceed under light irradiation and moderate conditions. This study provides a green photocatalytic route for the production of azo compounds and highlights a potential application for graphene. 相似文献
In recent decades, solar‐driven hydrogen production over semiconductors has attracted tremendous interest owing to the global energy and environmental crisis. Among various semiconductor materials, TiO2 exhibits outstanding photocatalytic properties and has been extensively applied in diverse photocatalytic and photoelectric systems. However, two major drawbacks limit practical applications, namely, high charge‐recombination rate and poor visible‐light utilization. In this work, heterostructured TiO2 nanotube arrays grafted with Cr‐doped SrTiO3 nanocubes were fabricated by simply controlling the kinetics of hydrothermal reactions. It was found that coupling TiO2 nanotube arrays with regular SrTiO3 nanocubes can significantly improve the charge separation. Meanwhile, doping Cr cations into SrTiO3 nanocubes proved to be an effective and feasible approach to enhance remarkably the visible‐light response, which was also confirmed by theoretical calculations. As a result, the rate of photoelectrochemical hydrogen evolution of these novel heteronanostructures is an order of magnitude larger than those of TiO2 nanotube arrays and other previously reported SrTiO3/TiO2 nanocomposites under visible‐light irradiation. Furthermore, the as‐prepared Cr‐doped SrTiO3/TiO2 heterostructures exhibit excellent durability and stability, which are favorable for practical hydrogen production and photoelectric nanodevices. 相似文献
Bi‐ and Y‐codoped TiO2 photocatalysts were synthesized through a sol‐gel method, and they were applied in the photocatalytic reduction of CO2 to formic acid under visible light irradiation. The results revealed that, after doping Bi and Y, the surface area of TiO2 was increased from 5.4 to 93.1 m2/g when the mole fractions of doping Bi and Y were 1.0% and 0.5%, respectively, and the lattice structures of the photocatalysts changed and the oxygen vacancies on the surface of the photocatalysts formed, which would act as the electron capture centers and slow down the recombination of photo‐induced electron and hole. The photocurrent spectra also proved that the photocatalysts had better electronic transmission capacities. The HCOOH yield in CO2 photocatalytic reduction was 747.82 μmol/gcat by using 1% Bi‐0.5% Y‐TiO2 as a photocatalyst. The HCOOH yield was 1.17 times higher than that by using 1% Bi‐TiO2, and 2.23 times higher than that by using pure TiO2. Furthermore, the 1% Bi‐0.5% Y‐TiO2 showed the highest apparent quantum efficiency (AQE) of 4.45%. 相似文献
A high internal phase emulsion polymerization (PolyHIPE) material, with iodine‐functionalized boron‐dipyrromethene (iodic‐BODIPY) immobilized on its surface, composes a porous heterogeneous organic photocatalyst (iodic‐BODIPY‐PolyHIPE). It shows high catalytic efficiency on the selective oxidation reaction of aromatic sulfides under visible light. The substrates were almost fully converted to their corresponding sulfoxides and no sulfones were observed. Most importantly, iodic‐BODIPY‐PolyHIPE shows >1.6‐fold reaction rate compared to the previous non‐inorganic heterogeneous photocatalysts. 相似文献
Nowadays, introducing self‐cleaning properties on various fabrics under daylight irradiation for automotive and upholstery application is in a central point of research. This can be achieved by application of metal‐doped TiO2 nano particles on the textile fabrics. Here, alkali hydrolysis of polyester fabric has been carried out along with synthesis of Cu2O/TiO2 nanoparticles in a single‐step process by using sonochemical technique. CuSO4.5H2O was used as a source of copper in the presence of glucose as reducing and stabilizing agent. Moreover, central composite design based on response surface methodology (RSM) was used to determine the role of variables (CuSO4.5H2O, glucose and pH) and their effects on the self‐cleaning properties and weight of the fabric. The self‐cleaning property was investigated by degradation of Methylene blue on the surface of the treated fabrics under daylight. Further, the tensile properties, colorimetric measurement, and washing fastness of the treated fabric produced in the optimum conditions were investigated. The morphology of Cu2O/TiO2 nanoparticles was examined using X‐ray diffraction and field emission scanning electron microscopy (FESEM). The new polyester fabric obtained through in situ synthesis of Cu2O/TiO2 nanoparticles can be used as a desirable stable fabric with high tensile strength and visible‐light self‐cleaning properties. 相似文献
As a typical photocatalyst for CO2 reduction, practical applications of TiO2 still suffer from low photocatalytic efficiency and limited visible‐light absorption. Herein, a novel Au‐nanoparticle (NP)‐decorated ordered mesoporous TiO2 (OMT) composite (OMT‐Au) was successfully fabricated, in which Au NPs were uniformly dispersed on the OMT. Due to the surface plasmon resonance (SPR) effect derived from the excited Au NPs, the TiO2 shows high photocatalytic performance for CO2 reduction under visible light. The ordered mesoporous TiO2 exhibits superior material and structure, with a high surface area that offers more catalytically active sites. More importantly, the three‐dimensional transport channels ensure the smooth flow of gas molecules, highly efficient CO2 adsorption, and the fast and steady transmission of hot electrons excited from the Au NPs, which lead to a further improvement in the photocatalytic performance. These results highlight the possibility of improving the photocatalysis for CO2 reduction under visible light by constructing OMT‐based Au‐SPR‐induced photocatalysts. 相似文献
Anatase TiO2 nanosheets with exposed {001} facets have been controllably modified under non‐thermal dielectric barrier discharge (DBD) plasma with various working gas, including Ar, H2, and NH3. The obtained TiO2 nanosheets possess a unique crystalline core/amorphous shell structure (TiO2@TiO2?x), which exhibit the improved visible and near‐infrared light absorption. The types of dopants (oxygen vacancy/surface Ti3+/substituted N) in oxygen‐deficient TiO2 can be tuned by controlling the working gases during plasma discharge. Both surface Ti3+ and substituted N were doped into the lattice of TiO2 through NH3 plasma discharge, whereas the oxygen vacancy or Ti3+ (along with the oxygen vacancy) was obtained after Ar or H2 plasma treatment. The TiO2@TiO2?x from NH3 plasma with a green color shows the highest photocatalytic activity under visible‐light irradiation compared with the products from Ar plasma or H2 plasma due to the synergistic effect of reduction and simultaneous nitridation in the NH3 plasma. 相似文献
Enhanced harvesting of visible light is vital to the development of highly efficient dye‐sensitized solar cells (DSSCs). Nanosilver‐decorated TiO2 nanofibers (Ag@TiO2 NFs) were synthesized by depositing chemically reduced Ag ions onto the surface of electrospun TiO2 nanofibers (TiO2 NFs). The prepared Ag@TiO2 NFs were coated with SiO2 (SiO2@Ag@TiO2 NFs) by using PVP as coupling agent for protecting corrosion of Ag nanoparticle by I?/${{\rm I}{{- \hfill \atop 3\hfill}}}$ solution. The fabricated SiO2@Ag@TiO2 NFs demonstrated a synergistic effect of light scattering and surface plasmons, leading to an enhanced light absorption. Moreover, an anode consisting of SiO2@Ag@TiO2 NFs incorporating TiO2 nanoparticles (NPs) increased light harvesting without substantially sacrificing dye attachment. The power conversion efficiency increased from 6.8 to 8.7 % for a thick film (10 μm), that is, 28 %. These results suggest that SiO2@Ag@TiO2 NFs are promising materials for enhanced light absorption in dye‐sensitized solar cells. 相似文献
A universal sequential synthesis strategy in aqueous solution is presented for highly uniform core–shell structured photocatalysts, which consist of a metal sulfide light absorber core and a metal sulfide co‐catalyst shell. We show that the sequential chemistry can drive the formation of unique core–shell structures controlled by the constant of solubility product of metal sulfides. A variety of metal sulfide core–shell structures have been demonstrated, including CdS@CoSx, CdS@MnSx, CdS@NiSx, CdS@ZnSx, CuS@CdS, and more complexed CdS@ZnSx@CoSx. The obtained strawberry‐like CdS@CoSx core–shell structures exhibit a high photocatalytic H2 production activity of 3.92 mmol h?1 and an impressive apparent quantum efficiency of 67.3 % at 420 nm, which is much better than that of pure CdS nanoballs (0.28 mmol h?1), CdS/CoSx composites (0.57 mmol h?1), and 5 %wt Pt‐loaded CdS photocatalysts (1.84 mmol h?1). 相似文献