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Eggshell membrane (ESM) has recently gained interest for various applications in the field of biomedical engineering, materials science and environmental engineering. It is a routinely generated waste material which makes it easily available and an affordable biomaterial. ESM is a protein-rich, thin, fibrous membrane composed of collagen and hyaluronic acid, a composition similar to that found in human tissues. The physicochemical properties of ESM make it suitable for tissue engineering applications such as regeneration of skin, bone, cartilage, tympanic membrane, nerve and blood vessels. Further, ESM has been used either as nanoparticles or as a platform to deliver nanoparticles for various therapeutic applications. The review discusses the intrinsic structural and chemical properties of ESM, the techniques to isolate ESM, the various forms in which it has been used and its varied tissue engineering and nanomedicine applications, thereby highlighting its potential as an ideal natural biomaterial for biomedical applications. It also highlights the challenges to the utility of ESM and the unmet needs. [ABSTRACT FROM AUTHOR]

Organic pollutants in wastewater are the biggest problem facing the world today due to population growth, rapid increase in industrialization, urbanization, and technological advancement. There have been numerous attempts to use conventional wastewater treatment techniques to address the issue of worldwide water contamination. However, conventional wastewater treatment has a number of shortcomings, including high operating costs, low efficiency, difficult preparation, fast recombination of charge carriers, generation of secondary waste, and limited light absorption. Therefore, plasmonic-based heterojunction photocatalysts have attracted much attention as a promising method to reduce organic pollutant problems in water due to their excellent efficiency, low operating cost, ease of fabrication, and environmental friendliness. In addition, plasmonic-based heterojunction photocatalysts contain a local surface plasmon resonance that enhances the performance of photocatalysts by improving light absorption and separation of photoexcited charge carriers. This review summarizes the major plasmonic effects in photocatalysts, including hot electron, local field effect, and photothermal effect, and explains the plasmonic-based heterojunction photocatalysts with five junction systems for the degradation of pollutants. Recent work on the development of plasmonic-based heterojunction photocatalysts for the degradation of various organic pollutants in wastewater is also discussed. Lastly, the conclusions and challenges are briefly described and the direction of future development of heterojunction photocatalysts with plasmonic materials is explored. This review could serve as a guide for the understanding, investigation, and construction of plasmonic-based heterojunction photocatalysts for various organic pollutants degradation. Herein, the plasmonic effects in photocatalysts, such as hot electrons, local field effect, and photothermal effect, as well as the plasmonic-based heterojunction photocatalysts with five junction systems for the degradation of pollutants are explained. Recent work on plasmonic-based heterojunction photocatalysts for the degradation of various organic pollutants in wastewater such as dyes, pesticides, phenols, and antibiotics is discussed. Challenges and future developments are also described. [ABSTRACT FROM AUTHOR]

Cellulose nanofibers (CNF) produced by bacterial were functionalized along the surface with 3-(trimethoxysilyl)propyl methacrylate (TMSPM). The chemical and crystalline structure of the material was confirmed with NMR, FTIR, EDX and XRD methods. Modified CNF were used as a crosslinker and reinforcer for polymerizable deep eutectic solvent (DES) based on acrylic acid and choline chloride. Dispersions of modified nanofibers in DES were applied as UV-curable ink for 3D printing. It was shown that shielding of -OH groups of the cellulose surface with TMSPM increased the quality of 3D printed filaments due to reduced CNF agglomeration. At the same time, surface methacrylic groups copolymerize with acrylic acid forming crosslinked ion gel. Elastic moduli of the prepared ion gels were identical to those of gels based on unmodified CNF and crosslinked with N,N'-methylenebisacrylamide. However, strength and the ultimate elongation of the material prepared in this work were 1.05 ± 0.08 MPa at 2700% that is significantly higher than those of the material prepared with unmodified CNF. [ABSTRACT FROM AUTHOR]

Nanostructured TiO2 has been extensively used for environmental and energy storage applications because of its high chemical stability, economical, non-toxic, and significant charge density. However, the poor electrical conductivity of TiO2 restricts its widespread practical application for high-performance supercapacitors. Hereby, in the present work, we investigated the influence of rare-earth/transition metal ions dual doping on electrochemical performance of TiO2 by synthesizing Ti0.90La0.05M0.05O2 (M = Y, Nd, V) nanostructures via facile sol–gel method. The effect of dual doping on the prepared TiO2-based nanostructures was studied for structural, electrical, and morphological characteristics by using XRD, FTIR, IV, and FESEM measurements. The XRD and FTIR results confirmed the successful dual doping with tetragonal phase formation of TiO2, and FESEM images revealed the formation of interconnected nanosphere type morphology by La/V doping. The CV, GCD, LSV, and EIS were performed to assess the electrochemical behavior of grown TiO2-based nanostructures for supercapacitor application. The electrochemical results exhibited the Faradic charge storage mechanism in all the fabricated nanostructures with pseudocapacitive nature. The CV results showed the highest specific capacitance (1070 F/g) for TiLaVO2 nanostructure than other grown samples. TiLaVO2 electrode also exhibited superior specific capacitance (803 F/g), energy density (28 Wh/kg), and power density (0.3 KW/kg), at a current density of 1 A/g in 1 M KOH electrolyte with better cycling stability 93% retention after 1000th cycle. The superior performance of TiLaVO2 electrodes was attributed to the formation of nanospheres that offer more electroactive sites for ion/electron transportation, higher electrical conductivity (IV results), higher current density (LSV results), and lower resistance and fast charge transfer (EIS results). The dual doping of different ions provoked size tunability, electrical conductivity improvement, and superior electrochemical characteristics of TiO2. Moreover, the facile strategy (dual doping) discussed in the present findings would provide insights for enhancing the electrochemical properties of TiO2 for use as supercapacitor electrode material. [ABSTRACT FROM AUTHOR]

Synthesis of graphene by reducing graphene oxide is the most propitious route for bulk graphene production. Reduction using eco-friendly techniques is more feasible to alleviate toxic chemicals use. Hence, determining the reduction potency of natural substances is vital for further development in the rGO synthesis process. In this work, an experimental investigation was carried out to determine the reduction efficiencies of various natural and thermal reduction techniques. The results were compared with GO reduced with synthetic routes. To ensure accurate determination of reduction potential, constant reaction parameters and the same GO batch synthesized were used. Thorough sample characterization was carried out using FTIR, XPS, FESEM, Raman spectroscopy, XRD and sheet resistance measurements. Results showed that among natural substances, tea powder showed better reduction efficiencies with 13 folds increase in electrical conductivity, whereas synthetic routes showed more than 29 folds increase in the electrical conductivity values as compared to unreduced GO samples. The C/O ratio quantified from XPS analysis was found to be 2.83, 2.98, 3.88 and 6.34 for reduction carried out using lemon extract, coffee, tea powder and direct thermal treatment, respectively. Based on the results, an eco-friendly reduction route using natural substances has the potential for efficient reduction; however, it needs further optimization. [ABSTRACT FROM AUTHOR]

This work demonstrates an effective strategy for preparing electrospun composite membranes consisting of polyacrylonitrile (PAN) nanofibers and a large amount of graphene oxide (GO) and reduced graphene oxide (rGO). Simple surface modification of GO with a cationic surfactant reliably results in the preparation of composite nanofibers as a function of GO content up to 30 wt%, which are subsequently transformed into membrane-type sheets via heat and pressure treatments. In addition, an in situ hydrazine treatment readily converts the integrated GO into rGO, which is confirmed by water contact angles, Raman, XRD, and infrared thermography. These series of composite membranes are then employed in the removal of methylene blue dye with and without solar-simulated light irradiation. The PAN–GO composite membranes possessing various oxygen-containing functional groups initially display higher decontamination capability of the dyes than PAN–rGO. Both composite membranes notably improve the removal of the dyes to over 90% in 3 h under the light irradiation where the degree of removal efficiency for the PAN–rGO composite membrane is detectably increased due to its enhanced photothermal heating property. Although integrating GO derivatives into polymer nanofibers is a challenging task due to their limited dispersity and miscibility, our developed approach readily results in the systematic loading of GO and rGO at a high-level content into PAN nanofiber membranes, allowing us to realize their general properties including photothermal heating properties for various applications. [ABSTRACT FROM AUTHOR]

Wood can be used for the in situ preparation of wood sponge using chemical treatment, which can be employed as absorbent for sewage treatment and exhibits the advantage of low cost, low density, high porosity, and environmental friendliness. Previous researches on wood sponge mainly focused on its various applications, while the influence rule and mechanism of treatment conditions such as pH and concentration of NaClO2 solution, as well as concentration of NaOH solution have not been fully understood. This challenge limits the manufacturing efficiency and further application of wood sponge for the production of absorption materials and so on. The study presented an effective strategy for preparing wood sponges via using a top–down chemical treatment on low-density balsa wood and paid more attention to the controlling rule of preparation parameters. At the condition that pH of 4.0 (NaClO2 solution), NaOH concentration of 7 wt%, and NaClO2 concentration of 3 wt%, wood sponge with a porosity of 96.47% can be obtained with good resilience and excellent absorption capacity. Excessive concentration of NaOH and NaClO2 will significantly affect the skeletal structure of the wood sponge. After the silylation treatment, the optimal wood sponge was endowed with oil and organic solvents absorption capacity of 2441–17,300 mg g−1; it can be also recycled by simple extrusion. This highly resilient and recyclable wood sponge with high porosity and oil absorption capacity can be potentially applied for environmental protection. [ABSTRACT FROM AUTHOR]

Despite the well-developed history of research on typical TiO2 semiconductors, the modification of their photon-to-electron catalytic performance by incorporating graphene quantum dots (GQDs) which possesses extraordinary properties such as tuned band gap, high mobility and excellent separation of charges, great absorption capacity in the visible light region, and high surface area is still in the primary stage. Since 2013, the investigations regarding the photodriven applications of the versatile GQDs/TiO2 heterojunction has been harvesting the emergent research interests considering the significantly enhanced performance in a range of environment-, energy-, and bio-related areas. The present review aims to provide detailed information about the recent developments in this emerging field and to provide a timely overview of potential applications of the star composite GQDs/TiO2. The recent information regarding the application of versatile GQDs/TiO2 composites as photocatalytic degradation, H2 generation via water splitting, solar cells, and sensors has been discussed. Recent reports suggested that the incorporation of GQD into the TiO2 noticeably increases the degradation efficiency, H2 production, power conversion efficiency of solar cells, as well as sensitivity and selectivity in sensors owing to the extended photon absorption, facilitated charge transfer, and quench electron–hole pair recombination. Besides, the advanced response of GQDs/TiO2 composite as a gas sensor can be ascribed to the enhanced ability to detect gas molecules under UV light illumination besides thermal sensing. Moreover, the common trend in the development of GQDs/TiO2 composites and insights into future perspectives have also been discussed. [ABSTRACT FROM AUTHOR]

We report herein a versatile new approach for improving the photodegradation performance of UiO-66 by introducing 2-methylimidazole through a straightforward in situ one-pot solvothermal method. The resultant complex UiO-66-M-0.7 has demonstrated a reaction rate constant of 0.0183 min−1 in the photodegradation of rhodamine B under visible light, which is 69.4% higher than that with unmodulated UiO-66. Further investigation has confirmed that the improved activity can be attributed to enhanced adsorption of the dye by the photocatalyst during the adsorption–desorption equilibrium. The main active species involved in the photodegradation process have been identified as h+ and O2−·. In addition, the complex has shown ideal stability in recycling tests and excellent activity in the degradation of methylene blue. This study provides a novel perspective for the future design of various photocatalysts with superior performance. 2-Methylimidazole-modulated UiO-66 exhibits increased catalytic performance in the photodegradation of rhodamine B (RhB) under visible light because of enhanced adsorption of RhB on the catalyst during the adsorption-desorption equilibrium. [ABSTRACT FROM AUTHOR]

Hierarchical hollow structures show particular properties and promising applications, and therefore have been attracting attention. To the best of our knowledge, ZnO/C hollow sphere constructed by octahedron has not been reported so far. In this paper, a solvothermal process has been developed to prepare precursor hollow spheres constructed by octahedron. The precursor can be converted to hollow ZnO/C spheres with well-preserved morphology via thermal decomposing. In order to research the formation mechanism, intermediate precursors were acquired at different reaction times, and a possible growth mechanism was also proposed. When the hierarchical ZnO/C hollow spheres constructed by octahedron were used as the adsorbents, the Langmuir model can well describe the adsorption isotherms. For Congo red and Pb(II), the maximum adsorption capacities are up to 392 and 314 mg g−1, respectively. Furthermore, the as-prepared ZnO/C displays good recyclability in the removal of Congo red. Our results provide new strategy for the synthesis of novel ZnO/C hollow sphere, which has promising adsorption ability for water treatment. [ABSTRACT FROM AUTHOR]

Bismuth vanadate as photoanode with suitable bandgap and appropriate valence band positions is generally very stable in aqueous solution and cheap, but the photochemical activity is usually limited by poor electron mobility and low oxygen evolution kinetics. Herein, we exhibit that the above-mentioned problems can be solved by introducing a foreign dopant (Mo6+) into the BiVO4 film to create a distributed n+-n heterojunction and combining the BiVO4 photoanode with cobalt–phosphate water oxidation catalyst to improve the oxygen evolution kinetic. We systematically study the relationship between the higher photoelectrochemical performance and Mo-doping and cobalt–phosphate (CoPi) modification by XRD, Raman, SEM, TEM, LSV, EIS, I–t, and Mott–Schottky measurements, and the CoPi-Mo:BiVO4 heterojunction photoanode shows a current density of 3.27 times higher than that of pristine BiVO4 photoanode. Then, we concentrate our attention on a novel perspective for understanding the photoelectrochemical mechanism of interfacial charge transfer with the Mo-doping and CoPi modification on the BiVO4 photoanodes. This work provides new insights into the rational design of novel photoanodes from various improvement strategies with high photoelectrochemical performance and further utilization for environmental practical applications. [ABSTRACT FROM AUTHOR]

Combining plasmonic noble metals with semiconductor materials has been considered to be an effective way to improve catalyst performance. In the present paper, Au nanoparticles (NPs) were decorated onto CVD-grown β-Ga2O3 nanowires (NWs) through a chemical reduction method. Different quantity of HAuCl4 solution was used to control the size and density of Au NPs. The photocatalytic activity of the Au-Ga2O3 NWs is evaluated by degrading rhodamine B (Rh B) under UV and visible light irradiation. It is found that the size and density of the Au NPs had a great influence on the photocatalytic efficiency of β-Ga2O3 NWs. And Ga2O3 NWs with Au NPs of ~ 5.7 nm size and ~ 420/μm2 density shows the best catalytic efficiency. Moreover, Au NPs attachment on the Ga2O3 could extend its photocatalytic activity towards the visible light irradiation, which is significant to efficient utilization more solar light. A jointly effect of both the interfacial Schottky potential field between Au NPs and β-Ga2O3 NWs and local surface plasma resonance excitation is proposed to contribute the enhancement effects. [ABSTRACT FROM AUTHOR]

Carbon dots (CDs) were facilely synthesized by one-pot pyrolyzing a lactic acid-ionic liquid (IL) gel with a relatively high yield of 34.9 wt%. The CDs, with a mean particle size of 4.4 nm and high thermal stability, were almost amorphous and capped by IL groups. The CDs-IL in water exhibited an obvious excitation-, concentration-, pH-dependent and high salt-tolerant photoluminescence property. Specifically, the CDs-IL emitted the strongest blue fluorescence at 454 nm under 365 nm excitation with a quantum yield of 16%. In addition, the CDs-IL, as a kind of water-based lubricant additives, greatly improved the tribological properties of base liquid. The loading capability of base liquid for steel-steel pair increased from 50 N to at least 80 N when only 0.015 wt% of CDs-IL was added. Meanwhile, the mean friction coefficient and wear volume of base liquid reduced by 57.5% and 64% at the load of 40 N, respectively. In addition, the friction-reducing and antiwear performance of CDs-IL was far superior to the CDs and IL, reflecting a synergetic lubrication effect between the IL groups and carbon cores. Based on the worn surface analyses, the CDs were prone to be squeezed out of the rubbing surfaces during the boundary shear friction process, while the CDs-IL were prone to quickly form ordered absorption layers on rubbing surfaces by electrostatic interaction between the IL groups and steel surface, which is of key importance for the formation of effective lubrication film to largely reduce friction and wear. [ABSTRACT FROM AUTHOR]

Polymers with high dielectric constants are widely used in electronic devices and electric systems. However, polymers exhibit low dielectric constants, which greatly limit their applications. Currently, ferroelectric ceramic fillers and conductive filler are commonly filled into polymer matrix to achieve enhanced dielectric constants. Unfortunately, even though the loading fraction of ferroelectric ceramic fillers exceeds 50 vol%, the enhancement of dielectric constant is still limited. On the contrary, although ultrahigh dielectric constant could be realized in conductor/polymer composites containing small loading fractions of conductive fillers, the loss is usually very high owing to severe leakage conduction. To overcome the shortcomings of the above-mentioned two types of high dielectric composites, this work combined them together and designed a series of trilayer polymer composites consisting of one carbon nanotube/polyimide composite layer sandwiched by two BaTiO3/polyimide composite layers. Fortunately, the trilayer architecture could effectively overcome the drawbacks of carbon nanotube/polyimide and BaTiO3/polyimide single-layer composites, hence the balanced dielectric constant and loss. When the BT content of the outer layer is 50 wt% and the carbon nanotube content of the middle layer is 4 wt%, the trilayer film possesses a high dielectric constant of ~ 35 @10 kHz, which is about 700% over pristine PI matrix (ε′ ≈ 5 @10 kHz). Meanwhile, the loss tangent of the trilayer composite (tanδ ≈ 0.03 @10 kHz) is still comparative to pristine PI (tanδ ≈ 0.01 @10 kHz). [ABSTRACT FROM AUTHOR]

Semiconductor photocatalysis is a promising technology for removing contaminants from water. Particularly, visible-light photocatalysis has attracted much attention because of its potential to utilize solar energy. However, nano-sized visible-light-driven photocatalysts easily aggregate during water treatment. Besides, it is difficult to recycle them from treated systems. Therefore, it is of great importance to develop visible-light-responsive immobilized photocatalysts with high activity. In this work, MWCNTs/Ag3PO4/polyacrylonitrile (PAN) ternary composite fiber membranes (TCFMs) with good photocatalytic performance were fabricated by electrospinning technique combined with in situ Ag3PO4 forming reaction. Due to the addition of MWCNTs, the band gap of MWCNTs/Ag3PO4/PAN TCFMs became narrower than that of Ag3PO4/PAN binary composite fiber membranes (BCFMs), which made MWCNTs/Ag3PO4/PAN TCFMs be able to use light at longer wavelengths. Compared with Ag3PO4/PAN BCFMs, the as-prepared MWCNTs/Ag3PO4/PAN TCFMs showed enhanced photocatalytic activity and stability for degrading rhodamine B (RhB) in batch processing systems, which mainly ascribed to fast electron transfer from Ag3PO4 to MWCNTs and the resulting high electron-hole (e−-h+) separation efficiency. Radical trapping experiments revealed that holes (h+) and superoxide radicals (·O2−) played primary roles in RhB degradation. In addition, the flexible MWCNTs/Ag3PO4/PAN TCFMs also showed potential practical application in the continuous wastewater treatment by a suitable photocatalytic membrane reactor. This work provides a facile approach to prepare flexible supported photocatalytic membrane with visible-light response, high activity and good stability. [ABSTRACT FROM AUTHOR]

Bisphenol A (2,2-bis(4-hydroxyphenyl) propane, BPA) is a typical endocrine disruptor in aquatic environment. The removal of BPA by adsorption is a simple and effective way. Mesoporous carbon (MC) and N-modified mesoporous carbon (NMC) were synthesized by the soft template method and used for BPA adsorption. The adsorption performance of MC and NMC was investigated by the batch and dynamic system, and compared with commercial activated carbon (AC). Additionally, the kinetics and isotherms of BPA adsorption on MC and NMC were also investigated. The specific surface areas and average pore sizes of MC and NMC were 687.8 and 579.6 m/g, 4.06 and 4 nm, respectively. The equilibrium adsorption capacity of MC and NMC was positively correlated with the initial BPA concentration, and negatively correlated with adsorbent dosages. The pH value of 3-8 was conducive to the adsorption of BPA on MC and NMC. Pseudo-second-order kinetic model and Freundlich isotherm model provided well fit for BPA adsorption on MC and NMC. Compared with AC, MC and NMC exhibited a higher adsorption capability and more stable recycling performance. In the dynamic adsorption tests, with the increase in BPA concentration and flow rate in the influent, the breakthrough time and saturation time are shortened. However, the increase in adsorption layer height extended the breakthrough time and saturation time. [ABSTRACT FROM AUTHOR]

ZrO-decorated ZnO (ZrO|ZnO) nanoparticles (NPs) have been synthesized by a facile co-precipitation method in the presence of cetyltrimethylammonium bromide (CTAB) surfactant. The ZrO amount in the NPs has been varied from 1.0, 2.0, 4.9, to 9.3% by weight. The resulting NPs are heterostructured and consist of a crystalline ZnO core (wurtzite phase) surrounded by an amorphous ZrO layer. X-ray diffraction analyses support this observation. The NPs show a narrow size distribution and are slightly elongated. Compared to pure ZnO NPs, the hybrid ZrO|ZnO ones show enhanced photocatalytic activity toward the degradation of Rhodamine B under UV-Vis light. Such enhancement has been partly attributed to the increased amount of oxygen vacancies when ZrO is incorporated into the NPs, as shown by X-ray photoelectron spectroscopy analyses. [ABSTRACT FROM AUTHOR]

The sintered TiO nanofilms were immersed in the aqueous solution of graphite oxide and then were thermally reduced to reduced graphene oxide (RGO), resulting in RGO-doped TiO photoanodes employed in the dye-sensitized solar cells (DSSCs). This preparation method for the reduced graphene oxide-TiO (RGO-TiO) photoanode could avoid the loss of RGO during the sintering process. The presence of RGO in the photoanodes was confirmed using Raman analysis, scanning electron microscopy, transmission electron microscopy, and energy-dispersive spectrometer. The amount of RGO in photoanode was obtained by thermo-gravimetric analysis. Other techniques such as X-ray diffraction, Brunauer-Emmett-Teller, electron energy loss spectroscopy, and X-ray photoelectron spectroscopy were used to characterize the composite materials of RGO-TiO. The J- V measurement of RGO-TiO-based DSSCs showed that the best photoelectric conversion efficiency ( η) of 6.85% is 11.7% higher than that of the pure TiO (P25-TiO)-based DSSCs. It was shown that RGO in the photoanode could facilitate the phase transition in TiO crystals (from anatase to rutile) resulting in the mixed crystals in the photoanodes. The existence of RGO and mixed-crystal structure of TiO changed the electronic transmission pathway, reduced the recombination rate of electron-hole pairs, and thus improved the η of DSSCs. [ABSTRACT FROM AUTHOR]

In this study, Ag-doped ZnO microplates were prepared via precipitation technique and further characterized by FESEM, EDS, XRD, FTIR, TGA, XPS, UV-DRS and RT-PL techniques. The outcomes indicated that Ag ions were well incorporated into ZnO lattice leading to the absorption of ZnO in visible region as well as effective charge separation. The photocatalytic experiments exhibited that Ag-doped ZnO microplates show higher catalytic activity (91%) than bare ZnO (71%) for the degradation of KTC drug under solar illumination. The photocatalytic degradation of KTC drug over Ag-doped ZnO microplates obeyed pseudo first-order kinetics model. Also, the role of active species was examined by the addition of several scavengers in the photocatalytic degradation system. The results indicated that h, OH, O and OH were considered as prime reactive species in photocatalytic degradation process. [ABSTRACT FROM AUTHOR]

ZnSe photocatalytic films made of $$ \left\{ {000 1} \right\} $$ -ended microdisks and $$ \left\{ {2\overline{1} \overline{1} 0} \right\} $$ -ended nanobelts have been successfully synthesized via a solvothermal route followed by annealing in Ar atmosphere. Zn foils are used as both the Zn source and the substrate, Se powder as the Se source, and ethylenediamine (en) as the solvent. Lower temperature and Se concentration prefers the formation of $$ \left\{ {000 1} \right\} $$ -faceted ZnSe microdisks, while higher temperature and Se concentration leads to the formation of $$ \left\{ {2\overline{1} \overline{1} 0} \right\} $$ -faceted ZnSe nanobelts. Photoluminescence spectra show that both samples exhibit a visible-light emission, and ZnSe microdisks have more defects than ZnSe nanobelts. ZnSe microdisks have a superior photocatalytic activity over ZnSe nanobelts in the degradation of rhodamine B under visible light. The higher photocatalytic activity of ZnSe microdisks is attributed to larger amount of $$ \left\{ {000 1} \right\} $$ facets and defects in the ZnSe microdisks. [ABSTRACT FROM AUTHOR]

Anatase TiO nanoparticles were synthesized from sol-gel processing, and they were used as a precursor for titanate nanotubes (TNT) formation. TNT were synthesized under reflux heating of anatase TiO in concentrated NaOH solution followed by repeated washing with distilled water and 0.1 M HCl. The nanotubular structure was preserved till 450 °C, above which nanorod formation started. The as-synthesized nanotubes were found to have mixed crystal structure of anatase and NaHTiO·nHO (where 0 < x < 2), contrary to what has been reported before. The XRD peaks of titanate were slightly shifted to higher angles upon calcination along with prominent anatase peaks. Complete transformation to nanorods occurred at 600 °C and crystal structure was transformed to NaTiO and anatase. Sodium presence in TNT was confirmed by EDX, and Na-O and H-O-H along with Ti-OH vibrations were found by FTIR. Ti-OH/H-O-H vibrations were less prominent for samples calcined at 500 °C and above, which confirms structural water loss is associated with morphological change. The as-synthesized TNTs had a specific surface area of 157 m g, and it decreased by increasing calcination temperature. TNTs were applied to methylene blue aqueous solution to observe their decolorization capability under UV irradiation. The as-synthesized TNTs showed enhanced photocatalytic decolorization as compared to anatase titania nanoparticles due to presence of Ti-OH groups and higher specific surface area. The photocatalytic activity reduced when TNTs were annealed at high temperatures. The changes in the photocatalytic activity are related to the existence of hydroxyl groups in the structure, decrease in specific surface area of annealed nanotubes, change in morphology from nanotubes to nanorods, and bandgap shift to visible light when TNTs were calcined at higher temperatures. [ABSTRACT FROM AUTHOR]

Because of the potential application in photoelectrochemical cells for water splitting, the synthesis of BiFeO (BFO) is receiving increasing attention. A simple, low-cost drop-casting route was used to synthesize Ti ions doped BiFeO thin films and the effects of the Ti ions doping on their crystal structure, morphology, and photoelectrocatalytic activity had been studied. X-ray diffraction results of Ti-BFO films showed that the doping of Ti ions lead to the distortion of crystal structure. Photoelectrochemical measurements indicated that the photoelectrocatalytic activities of BFO film doped with 5 % Ti ions showed the best performance. The UV-Vis absorption spectra of Ti-BFO films showed that the absorption wavelength of BFO doped with 5 % Ti had obvious shift and the band gap decreased. From the results of Mott-Schottky (M-S) plots, we calculated the positions of valence band (VB) and conduction band (CB) for Ti-BFO film. The outcomes showed that the band gap structure of BFO samples doped with 5 % Ti had more positive CB and more negative VB. The calculated photogenic charge carrier concentrations of BFO and Ti (0.05)-BFO were 5.07 × 10 and 6.32 × 10 cm, respectively. The reduced band gap and increased photogenic charge carrier concentration are the major factors contributing to the enhancement of photoelectrocatalytic performances of Ti-BFO films. [ABSTRACT FROM AUTHOR]

LaSrCoO (LSC)-CeGdO (GDC) nanocomposite materials were prepared by a modified sol-gel method to improve solid oxide fuel cell cathode performance in intermediate temperature. Metal acetates precursors and citric acid combined with ethylene glycol as complex agents were used in the sol-gel process. Nano foam-like GDC powders were introduced into the sol-gel process to get the nanocomposites with the GDC content in the range of 10-50 wt%. In addition, pure LSC nano powders were also synthesized for comparison. The crystalline phases, morphologies, and elemental distributions of the pure LSC and LSC-GDC composite powders were characterized, and their electrode performances were investigated with electrochemical impedance spectroscopy. The results showed the GDC particles were largely covered by LSC, and the optimal GDC content was 30 wt% for the LSC-GDC electrode performance in this study. [ABSTRACT FROM AUTHOR]

In this work, TiO2 nanoparticles/Cu nanowires (TiO2NPs@CuNWs) binary composites with tunable coverage of TiO2 nanoparticles were prepared by a facile method of mixing oleic acid-modified TiO2 nanoparticles with as-prepared Cu nanowires. Characterization studies including X-ray diffraction spectroscopy, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, and high-resolution transmission electron microscopy were applied to investigate the structure and morphology of the as-synthesized TiO2NPs@CuNWs binary composites. The photocatalytic activity of TiO2NPs@CuNWs binary composites was examined by photodegradation of methyl orange. The enhanced photocatalytic efficiency of TiO2NPs@CuNWs nanocomposites was ascribed to the moderate specific surface area, mesoporous structures, and the electron sink effect of the Cu nanowires. In principle, our investigation indicates that the TiO2@Cu self-assembled nanostructures can be a promising candidate of composite photocatalysts. [ABSTRACT FROM AUTHOR]

CdS nanowires were prepared by a paired cell method, using highly ordered porous anodic alumina (PAA) membranes as templates. The morphology, structure, and composition of these nanowires were characterized by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray spectroscopy (EDS), and selected area electron diffraction (SAED) pattern. SEM images indicated that nanowires arrays are highly ordered and coincide with the contours of PAA. The EDS analysis, combined with HRTEM images and SEAD patterns, confirmed the formation of CdS. The formation and growth mechanism of CdS nanowires, as well as the optical properties, were also analyzed in details. The results indicated that the formation and growth of CdS nanowires experience from initial nuclei, nanoparticles, linear pearl-chain structures to final nanowires, attributed to electrostatic adsorption and ions diffusion. A strong emission with a maximum around 430 nm was observed from the synthesized CdS nanowires, which was attributed to the recombination of trapped electron/hole pairs. The absorption edge in UV–Vis spectrum of CdS/PAA nanoarrays showed a blue shift due to the quantum confinement effects. The technique can be used to fabricate other compound nanowires and newly light-emitting semiconductor materials. [ABSTRACT FROM AUTHOR]