Titanium Dioxide Nanomaterials: Synthesis, Properties, Modifications, and Applications

Nano-sized TiO 2 photocatalytic water-splitting technology has great potential for low-cost, environmentally friendly solar-hydrogen production to support the future hydrogen economy. Presently, the solar-to-hydrogen energy conversion efficiency is too low for the technology to be economically sound. The main barriers are the rapid recombination of photo-generated electron/hole pairs as well as backward reaction and the poor activation of TiO 2 by visible light. In response to these deficiencies, many investigators have been conducting research with an emphasis on effective remediation methods. Some investigators studied the effects of addition of sacrificial reagents and carbonate salts to prohibit rapid recombination of electron/hole pairs and backward reactions. Other research focused on the enhancement of photocatalysis by modification of TiO 2 by means of metal loading, metal ion doping, dye sensitization, composite semiconductor, anion doping and metal ion-implantation. This paper aims to review the up-to-date development of the above-mentioned technologies applied to TiO 2 photocatalytic hydrogen production. Based on the studies reported in the literature, metal ion-implantation and dye sensitization are very effective methods to extend the activating spectrum to the visible range. Therefore, they play an important role in the development of efficient photocatalytic hydrogen production.

A review and recent developments in photocatalytic water-splitting using TiO2 for hydrogen production

6. Rehybridization of the Acceptor (RICT) 3908 7. Planarization of the Molecule (PICT) 3909 III. Fluorescence Spectroscopy 3909 A. Solvent Effects and the Model Compounds 3909 1. Solvent Effects on the Spectra 3909 2. Steric Effects and Model Compounds 3911 3. Bandwidths 3913 4. Isoemissive Points 3914 B. Dipole Moments 3915 C. Radiative Rates and Transition Moments 3916 1. Quantum Yields and Radiationless Deactivation Processes 3916

Structural Changes Accompanying Intramolecular Electron Transfer: Focus on Twisted Intramolecular Charge-Transfer States and Structures

The increasing human need for clean and renewable energy has stimulated research in artificial photosynthesis, and in particular water photoelectrolysis as a pathway to hydrogen fuel. Nanostructured devices are widely regarded as an opportunity to improve efficiency and lower costs, but as a detailed analysis shows, they also have considerably disadvantages. This article reviews the current state of research on nanoscale-enhanced photoelectrodes and photocatalysts for the water splitting reaction. The focus is on transition metal oxides with special emphasis of Fe2O3, but nitrides and chalcogenides, and main group element compounds, including carbon nitride and silicon, are also covered. The effects of nanostructuring on carrier generation and collection, multiple exciton generation, and quantum confinement are also discussed, as well as implications of particle size on surface recombination, on the size of space charge layers and on the possibility of controlling nanostructure energetics via potential determining ions. After a summary of electrocatalytic and plasmonic nanostructures, the review concludes with an outlook on the challenges in solar fuel generation with nanoscale inorganic materials.

Inorganic nanostructures for photoelectrochemical and photocatalytic water splitting

α‐Fe2O3 Nanotubes in Gas Sensor and Lithium‐Ion Battery Applications

Laser induced photocatalytic splitting of water into hydrogen and oxygen has been studied The activity of pure Fe 2 O 3 catalyst and various electron capture agents, such as Fe 3+ , Ag + , Al +3 , and Li + , in the water splitting process under the irradiation of a strong laser beam at 355 nm has been investigated for the first time The amounts of hydrogen and oxygen produced within a short span of time were quite substantial and the photonic efficiency achieved using pure Fe 2 O 3 was much higher than the reported conventional lamp based photocatalysis techniques The yields of hydrogen and oxygen produced were affected considerably by the addition of electron capture agents The highest electron capture activity was observed for Fe 3+  In addition to monitoring the activity of the Fe 2 O 3 catalyst for hydrogen and oxygen production, pH changes in the colloidal suspension during the photocatalytic process were also investigated The parametric dependence of the yield as a function of laser beam intensity, irradiation (exposure) time, and concentration of the active material was carefully studied

Production of hydrogen and oxygen by water splitting using laser induced photo-catalysis over Fe2O3

Laser induced photo-catalytic oxidation/splitting of water over α-Fe2O3, WO3, TiO2 and NiO catalysts: activity comparison

Molecular structure and fundamental vibrational frequencies of benzimidazole (BZI) are reported using ab initio-Hartree−Fock (HF) and density functional theory (DFT) methods at different levels of ...

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Normal Vibrational Mode Analysis and Assignment of Benzimidazole by ab Initio and Density Functional Calculations and Polarized Infrared and Raman Spectroscopy

Fluorescence and absorption spectra of 10-4 M thymine in aqueous solutions at different pH values are reported at room temperature. The shape of the fluorescence spectrum is found to change when the excitation wavelength is varied. The absorption spectra for the aqueous pH 4−8 thymine solutions in the range 240−300 nm are believed to include the diketo tautomer T1 and the enol−keto tautomer T2. Steady-state fluorescence spectra and ab initio calculations support the existence of these neutral species in their ground state. The lifetimes of the excited states of the T1 and T2 tautomers are 0.72 and 3.87 ns, respectively. Aqueous thymine solutions with pH values below pH 3 contain a protonated enol−keto form of T2 in addition to the major diketo-tautomer T1 in its neutral form. The lifetime of the protonated enol−keto form is 4.2 ns. On the other hand, thymine solutions with pH values above pH 8 contain mixtures of the neutral forms of T1 and T2 as well as their monoanioic forms. However, aqueous thymine so...

A. Suwaiyan

Papers

Production of hydrogen and oxygen by water splitting using laser induced photo-catalysis over Fe2O3

Laser induced photo-catalytic oxidation/splitting of water over α-Fe2O3, WO3, TiO2 and NiO catalysts: activity comparison

Normal Vibrational Mode Analysis and Assignment of Benzimidazole by ab Initio and Density Functional Calculations and Polarized Infrared and Raman Spectroscopy

Fluorescence of Thymine Tautomers at Room Temperature in Aqueous Solutions

Normal and twisted intramolecular charge-transfer fluorescence of 4-dimethylaminobenzonitrile in α-cyclodextrine cavities