- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Highly Selective Photocatalytic Reduction of o-Dinitrobenzene to o-Phenylenediamine over Non-Metal-Doped TiO2 under Simulated Solar Light Irradiation
摘要： Photocatalytic reduction and hydrogenation reaction of o-dinitrobenzene in the presence of oxalic acid over anatase-brookite biphasic TiO2 and non-metal-doped anatase-brookite biphasic TiO2 photocatalysts under solar simulated light was investigated. Compared with commercial P25 TiO2, the prepared un-doped and doped anatase-brookite biphasic TiO2 exhibited a high selectivity towards the formation of o-nitroaniline (85.5%) and o-phenylenediamine ~97%, respectively. The doped anatase-brookite biphasic TiO2 has promoted photocatalytic reduction of the two-nitro groups of o-dinitrobenzene to the corresponding o-phenylenediamine with very high yield ~97%. Electron paramagnetic resonance analysis, Transient Absorption Spectroscopy (TAS) and Photoluminescence analysis (PL) were performed to determine the distribution of defects and the fluorescence lifetime of the charge carriers for un-doped and doped photocatalysts. The superiority of the doped TiO2 photocatalysts is accredited to the creation of new dopants (C, N, and S) as hole traps, the formation of long-lived Ti3+ defects which leads to an increase in the fluorescence lifetime of the formed charge carriers. The schematic diagram of the photocatalytic reduction of o-dinitrobenzene using the doped TiO2 under solar light was also illustrated in detail.
关键词： selectivity,photocatalysis,non-metal-doped TiO2,nitroaromatic compounds,reduction
更新于2025-09-23 15:22:29
-
Tuning electronic and optical properties of TiO<sub>2</sub> with Pt/Ag doping to a prospective photocatalyst: a first principles DFT study
摘要： Using first-principles density functional theory, the modulated electronic and optical properties of TiO2 with Pt/Ag substitutional dopants with varying concentration are investigated. Our calculations reveal the significant decreasing trend in the band gap of TiO2 while increasing the Pt (direct band gap) and Ag (indirect band gap) impurity concentration from 4.17% to 8.33% to 12.5%. The spin-polarized density of states reveal strong hybridization between the impurity bands with Ti-(3d) and O-(2p) bands near the Fermi level. The charge transfer mechanism depicts the delocalized electron cloud forming a strong bonding between the dopants (Pt/Ag) and oxygen of TiO2. Moreover, the absorption spectra of the Pt doped TiO2 structures have a broad peak at the visible range of energy spectrum with maximum absorption up to 0.7×10?5cm?1. The calculated reflectivity, energy loss function and extinction coefficient shows the enhanced optical properties of doped TiO2 compared to its pristine form. The obtained results predict the way to tailor the optical properties of Pt/Ag-doped TiO2 as an efficient photocatalyst in the visible region.
关键词： Pt,Optical properties,Electronic structure,Photocatalyst,Ag doped TiO2
更新于2025-09-23 15:22:29
-
Effect of metal doped and co-doped TiO2 photocatalysts oriented to degrade indoor/outdoor pollutants for air quality improvement. A kinetic and product study using acetaldehyde as probe molecule
摘要： This study demonstrates the photocatalytic decomposition of an indoor air pollutant, acetaldehyde (CH3CHO), over 0.04 mol% metal-doped TiO2 (Mn-, Co- and Mn/Co-) nanoparticles activated by ultraviolet and visible irradiation. The photocatalytic activity, the photodegradation kinetics, and the ?nal product analysis were examined using a Static Photochemical Reactor coupled with a FTIR spectrophotometer. CH3CHO undergoes ef?cient decomposition over all photocatalysts under UV irradiation in the presence of one atmosphere N2 or synthetic air (SA). Metal doping causes substantial in?uence to photocatalysis by altering the amount of electron/hole pairs generated and/or the electron/hole recombination rates. Simulating the experimental results with pseudo-?rst order kinetics the corresponding degradation rate coe?cients were determined for each photocatalyst under UV irradiation and SA environment: kd UV(Mn-TiO2) = (1.9 ± 0.2)×10 ?1 h ?1, kd UV(Co-TiO2) = (2.8 ± 0.3)×10 ?1 h ?1, and kd UV(Mn/Co-TiO2) = (6.0 ± 0.7)×10 ?1 h ?1. These degradation kinetics under UV light irradiation are signi?cantly faster than undoped TiO2 revealing that the transition metal doping of TiO2 nanomaterials boosts the photocatalytic degradation of organic pollutants. Substantial decomposition of CH3CHO was achieved under visible light in the presence of oxygen over Mn-TiO2 with kd Vis(SA) = (0.44 ± 0.04)×10 ?1 h ?1 while for other samples no visible light photocatalysis was observed. CO2, CO, and H2O were the main oxidation products, with CO2 yields almost 100% under UV excitation, and CO yields up to 20% under UV and < 1% under visible excitation. Our experimental results suggest that Mn-TiO2 (0.04 mol%) nanoparticles may be considered as a potentially safe photocatalyst to remove acetaldehyde particularly from indoor atmospheric environments under visible irradiation, without yielding signi?cant toxic by-products. Other possible atmospheric implications are also discussed in the paper.
关键词： Metal-doped TiO2,Visible-ultraviolet photocatalysis,Photodegradation kinetics,Acetaldehyde,Indoor air pollution
更新于2025-09-23 15:21:21
-
Universal Elaboration of Al-Doped TiO <sub/>2</sub> as an Electron Extraction Layer in Inorganic-Organic Hybrid Perovskite and Organic Solar Cells
摘要： Fabricating an electron extraction layer (EEL) with a metal doping transition metal oxide (TMO) in inorganic–organic hybrid perovskite solar cells (PeSCs) and organic solar cells (OSCs) is a simple and efficient process for enhancing photovoltaic properties. Here, the universal benefits and common factors that influence both PeSCs and OSCs as a result of changes in Al-doped TiO2 properties are investigated. These common factors are identified in two separate mechanisms. The first involves surface smoothing of TiO2 films, which affects the formation of a high crystalline active layer and reduces recombination between the electron extraction and active layers. The second involves bandgap widening of TiO2, which reduces the activation energy and enhances the quenching efficiency of devices. These factors are demonstrated in various measurements. The results will help in understanding the fundamental benefits of Al-doped TiO2 in solution-processed thin-film solar cells.
关键词： perovskite solar cells,electron extraction layer,organic solar cells,Al-doped TiO2
更新于2025-09-23 15:21:01
-
Evaluation of electronic transport and optical response of two-dimensional Fe-doped TiO2 thin films for photodetector applications
摘要： We have carried out the structural, electronic and optical properties of Iron (Fe)-doped TiO2 thin films by sol-gel technique. The results reveal that the thin films form in a granular structure where particle-like grains cover the surface. Photophysical features of the thin films are performed by UV–vis spectrometry. The optical bandgap of undoped TiO2 thin film decreases from 3.17 eV to 3.05 eV with an increase in atomic ratios of Fe content, so the electron transfer is easier from the valence band to the conduction band. The current-voltage (I–V) and capacitance-voltage (C–V) characteristics of the undoped and Fe-doped TiO2 thin films are investigated under dark and various lighting intensities. Our results show that the photocurrents increase with increasing intensities of illumination. The photodiodes also show a decreasing capacitance with increasing frequency. From I–V and C–V plots, the photodiodes show rectifying properties and good photovoltaic behavior. Herein, the results display that the produced new Fe-doped TiO2 thin film samples can be used for photodetector applications.
关键词： Fe-doped TiO2,I-V,Photodiodes,Bandgap
更新于2025-09-23 15:21:01
-
Surface Photocatalytic Research of Fe -doped TiO2 (001) Based On the First-principles
摘要： In this paper,the first-principles based on density functional theory was used to study the Fe/TiO2(001) band gap width and adsorption energy of C6H6 molecules at different positions on the surface of the molecule with different doping methods and different Fe content. Calculation of the band structure and density of states of Fe-doped TiO2 nanoparticles shows that, the surface gap doping is more favorable than the substitution doping to reduce the band gap of TiO2,and when the doping concentration is 6.122%,the maximum reduction of the band gap width is 59.3% higher than that of pure TiO2.According to the comparement of adsorption energy, it works out that the benzene molecule is mainly about horizontal adsorption on the surface of TiO2(001).Within the scope of the study, with the increase of Fe doping concentration, The adsorption energy does not decrease as the band gap, when the Fe atoms doping concentration is 4.167%,the maximum increase of adsorption energy is 63.2%.
关键词： photocatalytic,Fe-doped TiO2,band gap,first-principles,adsorption energy
更新于2025-09-23 15:21:01
-
AIP Conference Proceedings [Author(s) 3RD INTERNATIONAL SCIENCES, TECHNOLOGY & ENGINEERING CONFERENCE (ISTEC) 2018 - MATERIAL CHEMISTRY - Penang, Malaysia (17–18 April 2018)] - Influence of calcination temperature on the characteristic and sonophotocatalytic activities of Fe-doped TiO2 particles
摘要： In this study, 3 wt% Fe-doped TiO2 particles were prepared by sol-gel method using tetrabutyl titanate and iron (III) nitrate nonahydrate as precursors. Calcination of the prepared samples was carried out at temperature of 200, 400, 600 and 800 °C for 2 h. The effect of calcination temperature on the composition, structure and morphology of Fe-doped TiO2 were characterized using Field Emission Scanning Electron Microscope (FESEM), Energy Dispersive X-ray Spectroscope (EDX) and X-ray Diffractometer (XRD). The FESEM images revealed changes in particle size from 34 to 148 nm for samples calcined at 200 to 800 °C, respectively. Meanwhile, XRD results demonstrated the presence of rutile phase in catalysts which were calcined above 600 °C. Sonophotocatalytic degradation of paracetamol using ultraviolet (UV) light and ultrasonic irradiation was performed to investigate the influence of calcination temperature on the catalytic activity of Fe-doped TiO2. Among all the calcined catalysts, the Fe-doped TiO2-600 achieved the highest degradation efficiency (74%) due to the presence of mixed anatase and rutile phases. This proved that calcination temperature is a critical parameter which affects the characteristics and catalytic activity of Fe-doped TiO2 catalyst in the sonophoto-degradation process.
关键词： Paracetamol,Sonophotocatalytic,Heat treatment,Fe-doped TiO2,Characteristics
更新于2025-09-23 15:21:01
-
Improving Interfacial Charge-Transfer Transitions in Nb-Doped TiO2 Electrodes with 7,7,8,8-Tetracyanoquinodimethane
摘要： Interfacial charge-transfer (ICT) transitions involved in charge-separation mechanisms are expected to enable efficient photovoltaic conversions through one-step charge-separation processes. With this in mind, the charge-transfer complex fabricated from TiO2 nanoparticles and 7,7,8,8-tetracyanoquinodimethane (TCNQ) has been applied to dye-sensitized solar cells. However, rapid carrier recombination from the conduction band of TiO2 to the highest occupied molecular orbital (HOMO) of TCNQ remains a major issue for this complex. In this study, to inhibit surface-complex recombinations, we prepared Nb-doped TiO2 nanoparticles with different atomic ratios for enhanced electron transport. To investigate the effects of doping on electron injection through ICT transitions, these materials were examined as photoelectrodes. When TiO2 was doped with 1.5 mol % Nb, the Fermi level of the TiO2 electrode shifted toward the conduction band minimum, which improved electron back-contact toward the HOMO of TCNQ. The enhancement in electron transport led to increases in both short circuit current and open circuit voltage, resulting in a slight (1.1% to 1.3%) improvement in photovoltaic conversion efficiency compared to undoped TiO2. Such control of electron transport within the photoelectrode is attributed to improvements in electron injection through ICT transitions.
关键词： photovoltaic conversion,Nb-doped TiO2,interfacial charge-transfer transition,7,7,8,8-tetracyanoquinodimethane
更新于2025-09-23 15:21:01
-
Enhanced photocatalytic activity under visible light by the synergistic effects of plasmonics and Ti3+-doping at the Ag/TiO2- heterojunction
摘要： A heterojunction of plasmonic Ag particles on Ti3+-doped macro-/meso-porous TiO2 framework consisting of parallel microchannels, denoted as Ag/TiO2-x, has been fabricated by a simple microwave-assisted process employing vitamin C as the reducing agent for forming TiO2-x framework followed by photochemical deposition of Ag particles. Charge transport and recombination processes were detected through transient photocurrent responses. The visible-light photocatalytic hydrogen production rate and the apparent reaction rate constant of RhB photodegradation with 3%-Ag/TiO2-x catalyst are about 5.3 and 14.0 fold higher than those with the pristine macro-/meso-porous TiO2 framework, respectively. A mechanism based on the synergistic effects of Ag plasmonics and Ti3+-doping at the Ag/TiO2-x heterojunction is proposed, which consistently explains the high photocatalytic performance in hydrogen evolution and the improved photocatalytic decomposition of RhB under visible light. This study demonstrates the effective route to synthesize new heterojunction photocatalytic materials with multifunctional properties using low-cost and rapid microwave processes.
关键词： Macroporous/mesoporous TiO2 microchannel,Ag/TiO2-x heterojunction,Ti3+-doped TiO2,Photocatalysis,Surface plasmon resonance
更新于2025-09-23 15:19:57
-
Ruthenium (Ru) doped Titanium Dioxide (P25) Electrode for Dye Sensitized Solar Cells
摘要： In this study, P25-titanium dioxide (TiO2) was doped with ruthenium (Ru) by systematically varying the Ru content at 0.15, 0.30, 0.45 and 0.6 mol%. The synthesized Ru-doped TiO2 nanomaterials have been characterized by X-ray diffraction (XRD), Raman spectroscopy, energy-dispersive X-ray (EDX) analysis, UV-visible (UV–Vis) spectroscopy, and electrochemical impedance (EIS) spectroscopy. The XRD patterns of undoped and Ru-doped TiO2 nanomaterials confirm the presence of mixed anatase and rutile phases of TiO2 while EDX spectrum confirms the presence of Ti, O and Ru. Further, UV-visible absorption spectra of doped TiO2 nanomaterial reveal a slight red shift on Ru-doping. The short circuit current density (JSC) of the cells fabricated using the Ru-doped TiO2 photoanode was found to be dependent on the amount of Ru present in TiO2. Optimized cells with 0.3 mol% Ru-doped TiO2 electrodes showed efficiency which is 20% more than the efficiency of the control cell (η = 5.8%) under stimulated illumination (100 mWcm?2, 1 sun) with AM 1.5 filter. The increase in JSC resulted from the reduced rate of recombination upon doping of Ru and this was confirmed by EIS analysis.
关键词： Ru-doped TiO2,P25-TiO2,dye sensitized solar cells
更新于2025-09-23 15:19:57