2.3. Evaluation of Photocatalytic Water Splitting 6507 2.3.1. Photocatalytic Activity 6507 2.3.2. Photocatalytic Stability 6507 3. UV-Active Photocatalysts for Water Splitting 6507 3.1. d0 Metal Oxide Photocatalyts 6507 3.1.1. Ti-, Zr-Based Oxides 6507 3.1.2. Nb-, Ta-Based Oxides 6514 3.1.3. W-, Mo-Based Oxides 6517 3.1.4. Other d0 Metal Oxides 6518 3.2. d10 Metal Oxide Photocatalyts 6518 3.3. f0 Metal Oxide Photocatalysts 6518 3.4. Nonoxide Photocatalysts 6518 4. Approaches to Modifying the Electronic Band Structure for Visible-Light Harvesting 6519

Semiconductor-based Photocatalytic Hydrogen Generation

Jenny Schneider,*,† Masaya Matsuoka,‡ Masato Takeuchi,‡ Jinlong Zhang, Yu Horiuchi,‡ Masakazu Anpo,‡ and Detlef W. Bahnemann*,† †Institut fur Technische Chemie, Leibniz Universitaẗ Hannover, Callinstrasse 3, D-30167 Hannover, Germany ‡Faculty of Engineering, Osaka Prefecture University, 1 Gakuen-cho, Sakai Osaka 599-8531, Japan Key Lab for Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology, Shanghai 200237, China

Understanding TiO2 photocatalysis: mechanisms and materials.

Photoinduced reactivity of titanium dioxide

Fujishima and Honda (1972) demonstrated the potential of titanium dioxide (TiO2) semiconductor materials to split water into hydrogen and oxygen in a photo-electrochemical cell. Their work triggered the development of semiconductor photocatalysis for a wide range of environmental and energy applications. One of the most significant scientific and commercial advances to date has been the development of visible light active (VLA) TiO2 photocatalytic materials. In this review, a background on TiO2 structure, properties and electronic properties in photocatalysis is presented. The development of different strategies to modify TiO2 for the utilization of visible light, including non metal and/or metal doping, dye sensitization and coupling semiconductors are discussed. Emphasis is given to the origin of visible light absorption and the reactive oxygen species generated, deduced by physicochemical and photoelectrochemical methods. Various applications of VLA TiO2, in terms of environmental remediation and in particular water treatment, disinfection and air purification, are illustrated. Comprehensive studies on the photocatalytic degradation of contaminants of emerging concern, including endocrine disrupting compounds, pharmaceuticals, pesticides, cyanotoxins and volatile organic compounds, with VLA TiO2 are discussed and compared to conventional UV-activated TiO2 nanomaterials. Recent advances in bacterial disinfection using VLA TiO2 are also reviewed. Issues concerning test protocols for real visible light activity and photocatalytic efficiencies with different light sources have been highlighted.

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A review on the visible light active titanium dioxide photocatalysts for environmental applications

Human skin is a remarkable organ. It consists of an integrated, stretchable network of sensors that relay information about tactile and thermal stimuli to the brain, allowing us to maneuver within our environment safely and effectively. Interest in large-area networks of electronic devices inspired by human skin is motivated by the promise of creating autonomous intelligent robots and biomimetic prosthetics, among other applications. The development of electronic networks comprised of flexible, stretchable, and robust devices that are compatible with large-area implementation and integrated with multiple functionalities is a testament to the progress in developing an electronic skin (e-skin) akin to human skin. E-skins are already capable of providing augmented performance over their organic counterpart, both in superior spatial resolution and thermal sensitivity. They could be further improved through the incorporation of additional functionalities (e.g., chemical and biological sensing) and desired properties (e.g., biodegradability and self-powering). Continued rapid progress in this area is promising for the development of a fully integrated e-skin in the near future.

25th Anniversary Article: The Evolution of Electronic Skin (E-Skin): A Brief History, Design Considerations, and Recent Progress

Spherically shaped plasmonic Au nanoparticles (NPs) of size 10 nm (±4 nm) have been decorated on TiO2 NPs for the synthesis of Au@TiO2 composites via an aqueous sol–gel method. The effects of the Au concentration on the optical properties, structural surface properties and photocatalytic activity have been investigated. The optical study indicated characteristics of the surface plasmon resonance (SPR) of Au NPs, which greatly red shifted the photo-absorption from UV to visible light. A Tauc plot showed a downward shift in the band gap energy due to the creation of a metal–semiconductor Schottky junction at the nano Au@TiO2 surface. The well crystallized mixed (anatase and rutile) TiO2 phase formation was investigated using X-ray diffraction studies. The decrease in the photoluminescence (PL) intensity with Au loading indicated an increase in the charge carrier separation. The porous nature of the synthesized photocatalyst material was observed in both Field Emission Scanning Electron Microscopy (FESEM) and Field Emission Transmission Electron Microscopy (FETEM). The homogeneous distribution of Au NPs over the entire TiO2 surface was examined using FETEM and was also confirmed by elemental mapping with STEM. The broadening and shifting of the Raman peak from 143.2 cm−1 to 144.7 cm−1 indicated the generation of crystalline defects such as vacancies and interstitial rearrangement, which may act as trapping sites for electrons. BET surface measurements revealed that the surface area increased from 29.19 m2 g−1 for bare TiO2 to 60.05 m2 g−1 for 2% (w/w) Au loading on TiO2. The synthesized porous Au@TiO2 composites exhibited a high photocatalytic activity for the splitting of H2O under natural solar radiation with the H2 generation rate of 399 μmol/0.1 g h−1, which is much higher than 132 μmol/0.1 g h−1 demonstrated by pristine TiO2 NPs. Along with the hydrogen (H2) generation via water splitting, photocatalytic Rhodamine-B degradation and the kinetics of the reaction were investigated in solar light. The rate was observed to be due to a pseudo-first order reaction.

Solar light active plasmonic Au@TiO2 nanocomposite with superior photocatalytic performance for H2 production and pollutant degradation

Solar energy in production of L-glutamate through visible light active photocatalyst—redox enzyme coupled bioreactor

Combination of nano‑sized hydroxyapatite (nHA) with restorative materials like glass ionomer cement and composite resins has been reported recently in 2011. The documented effects of these nano‑sized particles on the chemistry of these materials include increased biocompatibility and mechanical strength. nHA has been utilized for various applications like pulp capping agent, root canal sealer, filler for bleaching agents and toothpastes, osseo‑conductive bone graft etc., A nHA has been obtained using natural bovine bone, carbon template technique, hydroxyapatite‑chitosan template technique, wet precipitation technique, plasma spraying technique etc. This paper presents a review of the various aspects of nHA and summarizes the methods of fabrications and potential clinical applications of the same.

Nano‑hydroxyapatite and its contemporary applications

Lithium ion batteries (LIBs) with polymer based electrolytes have attracted huge attention due to the possibility of fabricating intrinsically safer and flexible devices. However, economical and eco-friendly sustainable technology is an oncoming challenge to fulfill the ever increasing demand. To circumvent this issue, we have developed gel polymer electrolyte (GPE) based on renewable polymers like cellulose triacetate (CTA) and poly (polyethylene glycol methacrylate) p(PEGMA) by using a photo polymerization technique. Cellulose triacetate offers good mechanical strength with improved ionic conductivity, owing to its ether and carbonyl functional groups. It is observed that the presence of open network has a critical impact on lithium ion transport. At room temperature, GPE PC exhibits optimal ionic conductivity of 1.8 × 10-3 Scm-1 and transference number of 0.7. Interestingly, it affords an excellent electrochemical stability window up to 5.0 V vs. Li/Li+. GPE PC shows a discharge capacity of 164 mAhg-1 ...

Facile Synthesis of Unique Cellulose Triacetate Based Flexible and High Performance Gel Polymer Electrolyte for Lithium Ion Batteries.

In the present investigation, we demonstrate a facile hydrothermal/solvothermal route to fabricate elegant Bi2S3 nanoflowers in large scale with highly oriented (001) surfaces. The synthesis route was observed to radically determine the overall morphology of the resultant product. Under hydrothermal conditions (12 h), formation of Bi2S3 flowers on nickel foil composed with the self-assembled tapered nanorods were obtained. Whereas after prolonged reaction time (24 h), formation of ultra long micro belts were observed. Interestingly, the architectured Bi2S3 flowers obtained by solvothermal route are seen to be composed with self assembled nanorods and it was also observed that the synthesis duration influences their shape, size, and areal density. Finding of such unique nanostructures on nickel foil arose by hydrothermal route exemplify a prominent photoenhanced field emission upon visible light illumination, which is attributed to the photoconductivity of Bi2S3. It is noteworthy that the field emission studies reveal low turn-on field of ~1.04 V/μm, required to draw an emission current density of ~0.1 μA/cm2, which is found to be lower than the earlier reports. The average emission current is observed to be stable over the duration of 3 h. In addition, field emission behavior of a single Bi2S3 flower (pasted on a tungsten microtip) has also been investigated. The high sensitivity and fast response of photoenhanced emission current switching indicate the Bi2S3 nanoflowers as a promising candidate for micro/nano-optoelectronic devices. .

Bharat B. Kale

Papers

Solar light active plasmonic Au@TiO2 nanocomposite with superior photocatalytic performance for H2 production and pollutant degradation

Solar energy in production of L-glutamate through visible light active photocatalyst—redox enzyme coupled bioreactor

Nano‑hydroxyapatite and its contemporary applications

Facile Synthesis of Unique Cellulose Triacetate Based Flexible and High Performance Gel Polymer Electrolyte for Lithium Ion Batteries.

Architectured Bi 2 S 3 nanoflowers: photoenhanced field emission study