- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Semiconductor Photocatalysis - Materials, Mechanisms and Applications || Alternative Approaches in Development of Heterogeneous Titania-Based Photocatalyst
摘要： Three alternative approaches for the development of heterogeneous photocatalysts are comparatively evaluated, namely (i) the use of molecular imprinting concept for the development of heterogeneous catalysts employing rhodamine B as template and sol–gel as synthesis route; (ii) the impregnation of TiCl4 on mixed nano- and micro-metric silicas, followed by calcination; (iii) the use of industrial and academic chemical residues as source of potential photocatalyst species impregnated on supports. All tests were carried on with rhodamine B as target molecule. For comparative reasons, photocatalytic tests were carried out with commercial titania (P25). The solids were characterized by nitrogen porosimetry, small-angle X-ray scattering (SAXS), zeta potential (ZP), diffuse reflectance spectroscopy in the ultraviolet region (DRS-UV), diffuse reflectance infrared Fourier transmission spectroscopy (DRIFTS), and Rutherford backscattering spectrometry (RBS). The supported catalysts resulting from silica nanoparticles and residue of the petrochemical industry achieved higher percentage of the dye degradation under ultraviolet (68.0 and 66.8%, respectively) radiation. The industrial waste reached the highest photocatalytic activity under visible (61%) radiation, while the commercial P25 achieved 82.0and 12.3% for ultraviolet and visible radiation, respectively. The textural and structural characteristics of the supported catalyst prepared with fumed silica and petrochemical waste (SiPe), namely the low-energy bandgap (1.8 eV), large surface area (280 m2 g?1), high pore volume (1.9 cm3 g?1), and high zeta potential value (?36.4 mV), may have been responsible for their high activity.
关键词： supported photocatalyst,molecular imprinting,Rhodamine B,titania,residue,silicas
更新于2025-09-23 15:21:01
-
Composite electrode of TiO2 particles with three kinds of crystal phases for significantly improved performance of dye-sensitized solar cells
摘要： A novel composite electrode of TiO2 particles with three kinds of crystal phases is fabricated for improving the dye-sensitized solar cell's performance. The photoelectric conversion efficiency of solar cell with the content of 30 wt% brookite nanocubes and 70 wt% P25 could reach 7.40%. It is obvious that brookite nanocubes are advantageous in terms of reduced charge recombination and higher voltage. On the other hand, P25 gives advantages of high surface area for dye loading and higher charge collection efficiency. This work shows a new photoelectrode design for enhanced energy conversion of DSSCs.
关键词： Composite electrode,Dye-sensitized solar cell,Brookite titania,Photoelectrochemcial property,Photovoltaic conversion efficiency
更新于2025-09-23 15:19:57
-
Establishing high photocatalytic H2 evolution from multiwalled titanate nanotubes
摘要： Black TiO2 in various forms has been investigated for numerous photochemical applications. In photocatalytic water splitting, “grey” titania can reach considerable H2 generation rates without using a noble metal co-catalyst. Up to now, a variety of anatase powders or other morphologies has been investigated in grey and black forms. Here we describe that hydrothermal titanate/anatase nanotubes can show a strong noble metal free photocatalytic activity. For optimized “blackening” conditions, a drastically higher photocatalytic H2 production can be obtained than for other nanoscale morphologies. This effect can further be improved with a very mild Pt doping that again shows a clearly stronger photocatalytic H2 production than comparably loaded nanopowders.
关键词： hydrothermal titania nanotubes,hydrogenation,absorption,photocatalysis,hydrogen evolution
更新于2025-09-23 15:19:57
-
Enhanced device performance with passivation of the TiO <sub/>2</sub> surface using a carboxylic acid fullerene monolayer for a SnPb perovskite solar cell with a normal planar structure.
摘要： Research on tin-lead (SnPb) perovskite solar cells (PSCs) have gained popularity in recent years due to their low bandgap which could be applied to tandem solar cells. However, most of the work are based on inverted PSCs using PEDOT:PSS as the hole transport layer as the normal structure PSCs show lower efficiency. In this work, the reason behind the low efficiency of normal structure SnPb PSCs is elucidated and the method to overcome the problem has been attempted through surface passivation. In the case of normal PSCs, at the interface between titania layer and SnPb perovskite there are many carrier traps observed originating from Ti-O-Sn bonds. In order to avoid the direct contact between titania and SnPb perovskite layer, the titania surface is passivated with carboxylic acid C60 resulting in efficiency increase from 5.14 % to 7.91 %. This will provide a direction of enhancing the efficiency of normal structure SnPb PSCs through heterojunction engineering.
关键词： passivation,Perovskite solar cells,Tin,titania,Lead,trap density,interface
更新于2025-09-23 15:19:57
-
Photoelectrocatalytic oxidation of methanol over RuO2MnO2Co3O4 supported porous anatase under visible light irradiation
摘要： Anatase supported heterogeneous photocatalyst consisting of RuO2, MnO2 and Co3O4 (1:13:13 ratio) was synthesized by a precipitation method and tested for photoelectrocatalytic (PEC) oxidation of methanol in 0.1 M KOH under visible light irradiation. The as-prepared photocatalyst was characterized by FTIR, UV-vis, XRD, Raman spectroscopy, FESEM/EDX, TEM, BET, XPS and TPR. The PEC studies by cyclic voltammetry indicated that the oxidation of methanol to CO2 and H2O upon exposure to visible light occurs between 400 to 800 nm. The smaller value of the charge transfer resistance (Rct) of the RuO2-MnO2-Co3O4 supported anatase TiO2 electrode indicates a faster rate of charge transfer at the electrode-electrolyte interface compared to the Pt/C catalyst, which could be promising for direct methanol fuel cell application.
关键词： methanol,Titania,photoelectrocatalyst,photoelectrooxidation
更新于2025-09-23 15:19:57
-
Photo-electrochemical Behavior of Silver Nanoparticles inside Mesoporous Titania: Plasmon induced charge separation effect
摘要： The self-assembly block copolymer method was used to synthesize mesoporous titania films and silver nanoparticles (NPs) were grown inside the films. Such silver NPs-titania films are known for their multicolor photochromic properties, due to a photo-oxidation reaction of silver in the presence of titania under light excitation which is attributed to a plasmon induced charge separation (PICS). Here, the photo-electrochemical properties of these composite films have been investigated at different light wavelengths and chemical environment in order to characterize the light-induced redox reactivity modifications. Cyclic voltammetry (CV) study shows that the Ag+ electro-reduction peak potential varies depending on the light irradiation, which determines the state of the silver nanoparticles complexed or not by titania.
关键词： cyclic voltammetry,Silver nanoparticles,photochromism,plasmon,mesoporous titania
更新于2025-09-19 17:15:36
-
Synthesis of highly crystalline photocatalysts based on TiO2 and ZnO for the degradation of organic impurities under visible-light irradiation
摘要： A TiO2–ZnO binary oxide system (with molar ratio TiO2:ZnO = 8:2) was synthesized by a hydrothermal method, assisted by calcination at temperatures of 500, 600 and 700 °C, using zinc citrate as the precursor of ZnO. The morphology (SEM, TEM), crystalline structure (XRD, Raman spectroscopy), diffuse reflectance spectra (DRS), chemical surface composition (EDXRF), porous structure parameters (low-temperature N2 sorption) and characteristic functional groups (FT-IR) of the TiO2–ZnO oxide materials were comprehensively analyzed. The novelty of this work is the observation of the coexistence of the crystalline structures of anatase and ZnTiO3 in TiO2–ZnO oxide materials. Moreover, it is shown that the obtained materials absorb visible radiation. The key stage of the study was the evaluation of the photocatalytic activity of the TiO2–ZnO binary oxide systems in the degradation of model organic pollutants: C.I. Basic Red 1, C.I. Basic Violet 10, C.I. Basic Blue 3 and 4-nitrophenol. For all synthesized materials, a high efficiency of degradation of the model organic impurities was demonstrated. The results show that the synthesized products may be materials of interest for use in the degradation of organic pollutants. Moreover, the kinetics of the photocatalytic degradation of selected organic compounds were determined based on the Langmuir–Hinshelwood equation, assuming a pseudo-first-order (PFO) reaction.
关键词： Titania,Zinc oxide,Photocatalysis,Binary oxide systems,Hydrothermal synthesis
更新于2025-09-19 17:15:36
-
Braiding kinetics and spectroscopy in photo-catalysis: the spectro-kinetic approach
摘要： The combination of kinetic and spectroscopic tools has become a key scientific methodology for the understanding of catalytic behavior but its application in photocatalysis has inherent difficulties due to the nature of the energy source of the reaction. This review article provides an overview of its use by, first, presenting mechanistically derived kinetic formulations and spectroscopic data handling methods including intrinsic expressions for light and, second, highlighting representative examples of application. To do it we consider universal catalytic systems, particularly (although not exclusively) titania-based materials, and the most frequent hole and/or electron triggered reaction schemes. This review also provides a general framework to pave the way for the future progress of the spectro-kinetic approach in the photocatalysis area.
关键词： spectroscopy,titania-based materials,kinetics,hole and electron triggered reactions,photocatalysis,spectro-kinetic approach
更新于2025-09-19 17:15:36
-
Plasmonic photocatalysis applied to solar fuels
摘要： The induction of chemical processes by plasmonic systems is a rapidly growing field with potentially many strategic applications. One of them is the transformation of solar energy into chemical fuel by the association of plasmonic metal nanoparticles (M NPs) and a semi-conductor (SC). When the localized surface plasmon resonance (LSPR) and the SC absorption do not match, one limitation of these systems is the efficiency of hot electron transfer from M NPs to SC through the Schottky barrier formed at the M NPs/SC interfaces. Here we show that high surface area 1wt.%Au/TiO2-UV100, prepared by adsorption of a NaBH4-protected 3 nm gold sol, readily catalyzes the photoreduction of carbon dioxide with water into methane under both solar and visible-only irradiations with a CH4 vs. H2 selectivity of 63%. Tuning Au NPs size and titania surface area, in particular via thermal treatments, highlights the key role of the metal dispersion and of the accessible Au-TiO2 perimeter interface on the direct SC-based solar process. The impact of Au NPs density in turn evidences the dual role of gold as co-catalyst and recombination sites for charge carriers. It is shown that the plasmon-induced process contributes up to 20% of the solar activity. The plasmon-based contribution is enhanced by a large Au NP size and a high degree of crystallinity of the SC support. By minimizing surface hydroxylation while retaining a relatively high surface area of 120 m2 g-1, pre-calcining TiO2-UV100 at 450°C leads to an optimum monometallic system in terms of activity and selectivity under both solar and visible irradiation. A state-of-the-art methane selectivity of 100% is achieved in the hot electron process.
关键词： Methane production,Gold nanoparticles,Titania,Selectivity,CO2 reduction,Hot electrons,Plasmonic photocatalysis,Solar fuels
更新于2025-09-19 17:15:36
-
A potentially more eco-friendly chemical pathway for production of high purity TiO2 from titanium slag
摘要： TiO2 is an important inorganic material which is commercially produced by either the chloride or the sulfate process. In general, the latter has lower cost and lower entry barrier than the former. However, the environmental impact associated with the sulfate process is more visible than the chloride process because the sulfuric acid with a low concentration (~20 wt%) cannot be cost-effectively recycled; therefore, it has to be neutralized, generating a large amount of wet and useless red gypsum (RG). In this research, a potentially more eco-friendly chemical pathway for TiO2 production from concentrated titanium ore, aka titania slag, is presented. The new method consists of three critical steps including transformation of the titania slag to a lower valence titanium sub-oxide by aluminothermic reduction, digestion by using mild acid, and controlled hydrolysis accompanied by acid recycling. As a result of the phase transformation, the digestion of titanium from the titanium feedstock becomes easier such that it is feasible to use relatively mild acid to replace concentrated acid, reducing the environmental impact from the red gypsum because the need for neutralizing the waste acid can be eliminated. High purity hydrous TiO2 can be prepared after hydrolysis, and the spent liquor can be effectively recycled back to the digestion unit.
关键词： Aluminothermic reduction,Titania slag,Controlled hydrolysis,Titanium dioxide,Mild acid digestion
更新于2025-09-19 17:15:36