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Photocatalytic oxidation of gaseous benzene, toluene and xylene under UV and visible irradiation over Mn-doped TiO2 nanoparticles
摘要： The photocatalytic oxidation of gaseous benzene, toluene and xylene (BTX) over un-doped, 0.1 and 1 wt% Mn-TiO2 nanoparticles under ultraviolet and visible irradiation was studied in atmosphere of synthetic air or inert gas. The photocatalytic decomposition efficiency and the oxidation products were determined using a Static Photochemical Reactor coupled with FTIR spectroscopy. BTX underwent efficient decomposition over Mn-TiO2 photocatalysts under UV irradiation, more with oxygen presence and less without oxygen. More important toluene and xylene went substantial decomposition over 0.1 mol% Mn-TiO2 under visible irradiation with oxygen presence. The main final oxidation products in the UV photocatalysis of BTX were CO2, CO and H2O, with CO2 and CO yields 4 and 2 respectively. The conversion percentage of benzene, toluene, and xylene to CO2 were 63.6%, 56.4%, 51.8%, and to CO 29%, 26.5%, 23.2%, respectively. In the visible photocatalysis of toluene and xylene the yields of CO were insignificant. Formation of carbon containing deposits on TiO2 surfaces was observed after extensive UV photocatalysis of toluene and xylene, and such by-products surface coverage may reduce the photocatalytic activity of TiO2 samples. Some aspects of the photocatalytic mechanism were examined.
关键词： Mn-doped TiO2,Visible - light photocatalysis,Photodegradation of Benzene,Indoors air pollution,Xylene,Toluene
更新于2025-09-23 15:23:52
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CuInS2 sensitized TiO2 for enhanced photodegradation and hydrogen production
摘要： A novel CuInS2/TiO2 (CIS-TO) heterojunction which displayed two different transfer pathways of photo-generated carries under UV–vis and Vis light irradiation was fabricated through a facile in-situ growth method. Under vis-light (λ ≥ 420 nm) excitation, 97.37% RhB (10 mg/L) was photodegraded with 20 mg of 1% CIS-TO photocatalyst within 90 min, and the degradation constant could up to 0.0415 min?1, which was about 8.28 times to pure TiO2 (0.00501 min?1) and the typical heterojunction was formed between CuInS2 and TiO2 to provide the photo-electrons transfer channel. Under UV–vis light irradiation, a Z-scheme heterojunction was formed to provide another highly effective electron transfer channel for hydrogen production and the hydrogen production rate could reach 785.4 μmol g?1 h?1 with 1% CIS-TO photocatalyst, which showed nearly 1.68 times than that of pure TiO2. The enhanced photocatalytic activity could be attributed to the synergistic effect of the sensitization and narrow band gap of CuInS2 which could effectively broaden the spectral response range, enhance the photon utilization and inhibit the recombination of photogenerated electrons and holes. Additionally, the high stability of the material was illustrated by the cycle experiments of photodegradation and hydrogen production.
关键词： Typical heterojunction,Sensitization,Z-scheme heterojunction,Photodegradation,CuInS2/TiO2
更新于2025-09-23 15:23:52
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Diffusion of Ar atoms implanted in a TiO2 matrix studied with Temperature Programmed Out-Diffusion?
摘要： The diffusion of noble gas argon in the near-surface region of rutile TiO2 has been explored with the Temperature Programmed Out-Diffusion (TPOD) method. The Ar atoms were deposited in a several-nanometer-deep layer of the single-crystal TiO2(110) surface by bombardment with 1–5 keV energy Ar ions. Subsequently, in the TPOD experiments this sample was heated at a linear rate and the out-diffusion of argon was monitored with a mass-spectrometer. Surface conditions were probed with Auger Electron Spectroscopy (AES) and Low-Energy Electron Diffraction (LEED). The experimental results were analyzed with the aid of numerical simulations. The measurements showed a dependence of the Ar diffusion rates on the concentration of buried argon and composition of the surface layer. The kinetic parameters of Ar diffusion in pristine rutile TiO2 were estimated as Ea = 104 kJ/mol and D0 = 6 ? 10?9 m2/s. A distinctive diffusion regime, related to the rock salt TiO phase formation, were identified.
关键词： Sputtering,TiO2,Low-energy ion implantation,Solid diffusion,Ar
更新于2025-09-23 15:23:52
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Optimizing one-dimensional TiO2 for photocatalytic hydrogen production from a water-ethanol mixture and other electron donors
摘要： This work is focused on synthesizing and employing one-dimensional (1D) titanium dioxide (TiO2) for hydrogen (H2) production. Based on using electron donors (EDs) (ethanol, methanol, formic acid and 1,2,3 propanetriol), the increased H2 production, when compared to P25 TiO2 nanoparticles, was due to the large specific surface area (SSA) and enhanced electron mobility of 1D TiO2. The impact of the 1D TiO2 synthesis reaction conditions (temperature, NaOH concentration and the TiO2 precursor concentration) on the photocatalytic H2 production rate was evaluated using a 3-factor 3-level Box Behnken design (BBD). The BBD model demonstrated that the temperature and the NaOH concentration significantly affected the 1D TiO2 phase structure, crystal size, SSA, bandgap and the photocatalytic H2 production rate. The phase structure and crystal size of 1D TiO2 were key factors affecting the H2 production rate. 1D TiO2 containing an anatase phase with a mean crystal size of 20.1±0.2 nm was synthesized at 126oC, 15 M NaOH and 49 g·L-1 TiO2. The maximum H2 production rate of 475±12 μmol·h-1 (quantum efficiency (ε) = 20.2±0.5%) for the 1D TiO2 sample was significantly enhanced when compared to commercial TiO2 P25. The H2 production rate for the optimized 1D TiO2 was significantly enhanced by decorating the structure with Pt and Au. Hydrothermal synthesized of 1D TiO2 provided an efficient and low cost method for producing H2 from ethanol, methanol, formic acid and 1,2,3 propanetriol.
关键词： hydrogen production,hydrothermal,1D titanium dioxide,TiO2-B,anatase,photocatalyst,quantum yield
更新于2025-09-23 15:23:52
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24.5: Back-Channel-Etched a-IGZO TFTs with TiO <sub/>2</sub> :Nb Protective Layer
摘要： A back-channel-etched (BCE) process for the fabrication of a-IGZO TFTs is demonstrated, in which conductive TiO2:Nb (TNO) thin film is used to serve as protective layer for the a-IGZO active layer. TNO film could excellently protect a-IGZO due to its ultra-small surface roughness. With treatment by N2O plasma + 200°C annealing, the conductive TNO can be converted into an insulator to serve as an in situ passivation layer. Besides, the TNO in the source–drain (S-D) region remain conductive due to the protection of S-D electrodes, which could be proved by the XPS results. Compare with the conventional device without TNO protective layer, the S-D parasitic resistance (RSD) of devices with 1 nm and 5 nm TNO is significantly reduced. The positive bias stress stability is improved as well for the devices with TNO in situ passivation layer.
关键词： amorphous indium gallium zinc oxide (a-IGZO),Nb doped TiO2 (TNO),thin film transistors (TFTs),back-channel-etched (BCE) process
更新于2025-09-23 15:23:52
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Facile green synthesis of Degraded-PVA coated TiO2 nanoparticles with enhanced photocatalytic activity under visible light
摘要： Grafting with conjugated structures has been proven to be an effective strategy to enhance the visible-light photocatalytic activity of TiO2, however, the preparation of conjugated structures modified TiO2 nanoparticles usually involves several tedious treatment steps and large amounts of organic solvents. In this research, a facile and green method to synthesize Degraded-PVA coated TiO2 (TiO2@D-PVA) nanoparticles containing conjugated structures was prepared. This method avoided using organic solvents and successfully coated D-PVA onto the surface of TiO2 just via physical mixing, centrifugation, and calcination. In addition, the content of D-PVA in TiO2@D-PVA could be controlled by the concentration of the PVA solution. Under visible light irradiation, the TiO2@D-PVA containing approximately 5 wt% D-PVA demonstrated an optimal photocatalytic activity which is 5.5 times higher than that of commercial P25 TiO2 nanoparticles. The Ti-O-C bonds and the conjugated structures in D-PVA could facilitate the electron transfer between D-PVA and TiO2, thus contributing to the enhanced visible light photocatalytic activity.
关键词： TiO2,photocatalytic activity,PVA,visible light
更新于2025-09-23 15:23:52
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Facile synthesis of thin black TiO2 ? x nanosheets with enhanced lithium-storage capacity and visible light photocatalytic hydrogen production
摘要： In combination of a facile and scalable solvothermal method and solid-phase reduction reactions, a novel two-dimensional black TiO2 ? x nanosheet (TiO2 ? x NS) with high specific surface area of 108 m2 g?1 and nearly total solar spectral absorption capability have been successfully prepared. With careful characterizations, the novel TiO2 ? x NS showed enhanced electrochemical performance and visible-light photocatalytic activity than those of their white TiO2 nanosheet (TiO2 NS) precursors. The black TiO2 ? x NS electrode delivered a reversible specific capacity of 160 mA h g?1 even after cycling at 0.5 C (1 C = 190 mA h g?1) for 300 times, which was significantly higher than the corresponding white TiO2 NS electrode (104 mA h g?1). Meanwhile, the TiO2 ? x NS also exhibited enhanced ability of visible-light photocatalytic hydrogen production than that of the white TiO2 NS. It is expected that making white TiO2 NS into black ones is an effective way to design the photocatalysts with visible light response and the anodes with long lifetime and high rate performance in lithium ion batteries. The novel black TiO2 ? x NS could find potential applications in the field of environmental management and energy storage and conversion.
关键词： Solvothermal method,Photocatalysis,Black TiO2 ? x nanosheets,Anodes
更新于2025-09-23 15:23:52
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Visible light sensitive Ag/TiO2/graphene composite as a potential coating material for control of Campylobacter jejuni
摘要： Infectious diarrhea caused by the food borne pathogen, Campylobacter jejuni, is a major threat to public health worldwide leads high incidence of child mortality each year. In the present study, hydrothermal synthesis of Silver-Graphene-TiO2 nanocomposites along with TiO2, TiO2-Graphene and TiO2-silver nanocomposites was done and the samples were characterized using X-ray diffraction (XRD), tunneling electron microscopy (TEM) and UV-Vis Spectroscopy. Effect of silver and graphene addition on the broad spectrum antibacterial ability of TiO2 was studied under visible light. Moreover, the effects on bacterial survival, membrane integrity, cellular motiltiy and biofilm formation of C. jejuni were also evaluated. A synergetic effect of silver and graphene on Silver-Graphene-TiO2 nanocomposites was observed as indicated by its increased visible light sensitivity and enhanced antibacterial activity under visible light compared to its parent derivatives. Silver-Graphene-TiO2 composites effectively reduced growth and caused leakage of protein and DNA from C. jejuni cell. Atomic Force Microscopy was used to confirm bacterial cell damage. Besides, it also reduced motillity, hydrophobicity and autoaggregation of C. jejuni and showed excellent inhibition of biofilm formation. Furthermore, no significant cytotoxicity of synthesized nanoparticles was observed in human cell lines. We propose that Silver-Graphene-TiO2 composites can be used as effective antimicrobial agents to control the spread of C. jejuni by preventing both bacterial growth and biofilm formation.
关键词： TiO2,Campylobacter jejuni,photocatalytic,nanocomposite,biofilm,graphene,cytotoxicity,silver
更新于2025-09-23 15:23:52
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Spatial dual-electric fields for highly enhanced the solar water splitting of TiO2 nanotube arrays
摘要： Efficient charge separation is essential for improving the photo-conversion efficiency in both photocatalytic and photoelectrochemical (PEC) water splitting. Herein, we have demonstrated the selective spatial-construction of Au nanolayer and SrTiO3 nanocubes on inner and outer surfaces of TiO2 nanotubes for enhancing the charge separation and PEC activity. More specifically, the outer SrTiO3 nanocubes with a spontaneous ferroelectric polarization could effectively engineer the electrical band bending of TiO2 nanotubes, facilitating hole transfer to the electrode/electrolyte interface for water oxidation. Meanwhile, the inner Au nanolayer with a favorable plasmonic electric-field induced by the visible light promote charge separation and rapid electron transfer to the counter electrode for hydrogen generation. Benefiting from the spatial dual-electric fields, this SrTiO3/TiO2/Au ternary-photoanode exhibits a significantly enhanced photocurrent density of 2.11 mA cm?2 at 1.23 V (vs. RHE), which is nearly 3.5 times higher than that of the pristine TiO2 nanotube arrays. Additionally, a low onset potential (~ 0.17 VRHE) for water oxidation as well as an excellent PEC stability has also been achieved. These demonstrations may provide a new strategy toward the rational construction of highly efficient PEC water splitting systems.
关键词： TiO2 nanotube,Water splitting,Plasmonic,Ferroelectric
更新于2025-09-23 15:23:52
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Energy diagram analysis of photoelectrochemical water splitting process
摘要： Photoelectrochemical (PEC) water splitting process is thoroughly revisited based on the energy diagram to elucidate the experimental observations. The TiO2 nanorod structure is studied as the model system for the photoanode of the PEC cell due to its stability in both acidic and basic solutions. The photocurrents with the external bias are examined under the various electrolytes of H2SO4, NaCl, and NaOH. The energy diagrams of the whole PEC system related to the water splitting process are interactively constructed in three-electrode configuration with the vacuum level as the common reference. Electrode potentials and photocurrents measured with the external bias in dark and under light are systematically correlated with the energy diagram of the PEC system. The pH dependent flat-band potential is explained by applying the pH dependent Helmholtz layer potential at the interface. In addition, the distribution of the applied potential in the PEC system during the water splitting process is understood by in-depth understanding of the energy band diagram.
关键词： band analysis,TiO2 nanorod,photoelectrochemical water splitting
更新于2025-09-23 15:23:52