Unique TiO2 Research Articles

Unique flake-shaped sulfur morphology favored by the binder-free electrophoretically deposited TiO2 layer as a promising cathode structure for Li-S batteries

Metal oxides have been extensively studied as catalyst additives in Li-S batteries due to their high affinity for soluble lithium polysulfides (LiPSs). The present study developed a novel carbon nanomaterials- and binder-free 3D sulfur host by electrophoretic deposition (EPD) of TiO2 nanoparticles on carbon fiber paper (CFP). Benefiting from the unique well-connected TiO2 porous layer formed by EPD, the initial discharge capacity of Li-S battery was increased from 1160 mAh g−1 in conventional cast TiO2/binder/S cathode (Cast:CFP/PVDF/TiO2/S) to 1310 mAh g−1 in the EPD:CFP/TiO2/S cathode, along with an overpotential drop of 16 %. Electron microscopic studies at 100% state-of-charge (SoC) revealed that while notorious sulfur particulates were formed on Cast:CFP/PVDF/TiO2/S, the surface of EPD:CFP/TiO2/S was covered with flake-shaped sulfur precipitates. The formation of sulfur flakes effectively suppressed pulverization in EPD:CFP/TiO2/S, leading to superior electrochemical performance and cycle life. Microstructural studies and real-time EIS investigations revealed that sulfur flakes nucleated across the Li2S matrix at the initial stages of charge and grew vertically from the sulfur/TiO2 interface. The preferential growth mechanism of sulfur flakes was attributed to the superior surface conductance of the EPD-TiO2 film enabled by the ordered clusters formed during EPD, enhancing the kinetics of electrocatalytic reactions of polysulfides at the TiO2/sulfur interface. Our results show that developing novel methods to modify the morphology of secondary sulfur upon cycling is critical for enhancing charge-discharge performance in Li-S batteries.

Multidimensional Engineering to Construct Ru/TiO2 Catalysts Enriched with Pores and Ti3+ Defects for Highly Efficient Selective Hydrogenation of Benzene

AbstractStructural engineering, coupled with crystalline phase engineering and surface engineering, serves as a practical and effective strategy for enhancing catalytic performance through the fine design of catalysts in terms of their structure, physical phases and surface defects. In this work, a set of strategies were employed for structural transformation and crystalline phase transition of Ru/TiO2 catalysts, utilizing multidimensional regulation. Ru nanoparticles loaded on a unique TiO2 nanosheet flowers (Ru/TSFs) enriched with pores and Ti3+ defects were prepared by solvothermal and impregnation‐chemical reduction methods. The Ru/TSFs exhibited an outstanding catalytic performance in the reaction of selective hydrogenation of benzene for the preparation of cyclohexene, with a selectivity of 79 % and a maximum yield of 52.8 % along with a benzene conversion of 45.9 % and a good stability. The excellent catalytic performance attributes to the distinctive structure of three‐dimensional nanosheet flowers, which offers a high specific surface area and improvs the effective contact between the catalyst and the reaction substrate. Meanwhile, the porous Ru/TSFs exhibit exceptional hydrophilicity and abundant Ti3+ defects on their surface, which is quite favorable for the desorption of cyclohexene from the reaction system, thus improving the selectivity of cyclohexene. The multidimensional engineering may provide an efficient approach for constructing high‐performance loaded catalysts for potential industrial applications.

Thermal transport in nanofluid across a radiated permeable sheet with irreversible effects based on the shape of the particles

Purpose The purpose of this study is to examine the flow and heat transfer performance of titanium oxide/water and copper/water nanofluids with varying nanoparticle morphologies by considering magnetic, Joule heating and viscous dissipation effects. Furthermore, it studies the irreversibility caused by the flow of a hydromagnetic nanofluid past a radiated stretching sheet by considering different shapes of TiO2 and Cu nanoparticles with water as the base fluid. Design/methodology/approach In this study, the authors investigated entropy production in an unsteady two-dimensional magneto-hydrodynamic nanofluid regime using water as the base fluid and five unique TiO2 and Cu nanoparticle morphologies. Using appropriate similarity transformations, the controlling nonlinear system of partial differential equations is transformed into a system of ordinary differential equations. The shooting technique with Runge–Kutta method was then used to solve these equations quantitatively. The findings of this study are depicted graphically, and the skin friction corresponding to various nanoparticle geometries and physical parameter variations is tabulated. Findings To assess the reliability of the current findings, a tabular representation of the data was compared to that of previously published studies. It is noted that a reduction in thermal energy was detected as a result of the higher levels of Prandtl number (Pr). It is further analysed that the highest heat energy generation of TiO2 nanoparticles was larger than that of Cu nanoparticles. The most important finding was that the sphere-shaped Cu/H2O nanofluid had the lowest velocity and greatest temperature. Also, Cu nanoparticles in the shape of platelets generate the most entropy, while TiO2 nanoparticles in the shape of spheres generate the least. Originality/value To the best of the knowledge of the authors, the attempt to investigate the previously unexplored shape effects of TiO2 and Cu nanoparticles on the heat transfer enhancement and inherent irreversibility caused by hydromagnetic nanofluid flow past a radiated stretching sheet with magnetic, Joule heating and viscous dissipation effects. This study fills this gap in the existing literature and encourages scientists, engineers and businesses to do more research in this area. This model can be used to improve heat transfer in systems that use renewable energy, thermal management in industry and the processing of materials.

Studying the effects of processing parameters in the aerosol-assisted chemical vapour deposition of TiO2 coatings on glass for applications in photocatalytic NOx remediation

Herein, we employ an aerosol-assisted method (AA-CVD) to produce TiO2 on window glass and study how the process parameters affect their photocatalytic activity towards NOx (NO + NO2) remediation. A range of process parameters are explored to produce 50 unique TiO2 coatings with wide ranging physicochemical properties. The physicochemical properties were examined using X-ray diffraction (XRD), atomic force microscopy (AFM), UV–visible transmission spectroscopy and transient absorption spectroscopy (TAS), and the photocatalytic activity towards NO gas was measured using protocol akin to the ISO (22197-1:2016). The most active sample showed an NO removal of ∼14.4 ± 1.7 % and NOx removal of ∼5.4 ± 0.77 %, which was ∼40 and ∼25 times higher than that of a commercially available self-cleaning window. The links between the process parameters, physicochemical properties and photocatalytic activity were studied in depth, where it was seen that the three most influential physicochemical properties on the observed activity were surface roughness, charge carrier population and charge carrier lifetime. Therefore, we recommend that these properties be targeted in the rational design of more active coatings for applications in photocatalytic NOx remediation.

Electro-catazone treatment of ozone-resistant drug ibuprofen: Interfacial reaction kinetics, influencing mechanisms, and degradation sites

Electro-heterogeneous catalytic ozonation (E-catazone) is a promising advanced oxidation process using a unique TiO2 nanoflower (TiO2-NF)-coated porous Ti anode. This study investigated interfacial reaction kinetics and the influencing mechanism of E-catazone degrading ozone-resistant drug ibuprofen. An elementary reactions library of the E-catazone process was established. The kinetic rate of key interfacial reactions under different operation parameters was quantitatively resolved. It was found that parameters such as current, initial pH, O3 concentration, and flowrate mainly affect •OH formation and ibuprofen removal via influencing three key interfacial reactions including anodic TiO2-NF surface hydroxylation, subsequent TiO2-NF‒OH/O3 heterogeneous catalysis, and cathodic generation of H2O2. In addition, the degradation pathways and sites of ibuprofen were also predicted via theoretical chemistry calculation, showing that •OH attacked C(12), C(11), or C(6) atom of the benzene ring in the ibuprofen via a radical adduct formation pathway. The results of this study will guide the application of the E-catazone process in the efficient removal of ozone-resistant drugs.

In Situ Dual-Template Method of Synthesis of Inverse-Opal Co3O4@TiO2 with Wideband Microwave Absorption.

A unique porous TiO2 with Co3O4 nanoparticles anchored in (Co3O4@TiO2) is prepared by a dual-templating method for promoting electromagnetic microwave absorption (EMA). The as-prepared Co3O4@TiO2 possesses a three-dimensional (3D) ordered macroporous TiO2 skeleton and plenty of mesopores, as well as small Co3O4 nanoparticles that coexisted in the macropore walls of the TiO2 skeleton. The introduction of Co3O4 can increase the magnetic loss as well as suppress impedance mismatch, resulting in the regulation of the EMA performance. The synergetic effect of the TiO2 porous framework and Co3O4 nanoparticles with proper ratio promote microwave absorption performance. Therefore, Co3O4@TiO2-2 with 25 wt % Co3O4 nanoparticles content displays a strong and ultrawide effective absorption band (EAB) performance. The Co3O4@TiO2-2 presents a strong reflection loss of -53.9 dB at 2.95 mm. Moreover, it obtains a super broad EAB of ∼12.5 GHz at 5.0 mm. This dual-templating approach for a well-controlled porous structure could be a facial strategy for the development of high-performance electromagnetic wave absorbers.

Rational synthesis and lithium storage properties of hierarchical nanoporous TiO2(B) assemblies with tailored crystallites and architectures

In comparison to the common anatase, rutile and brookite phases, the bronze phase TiO2 (TiO2(B)) is rarely prepared, and obtaining unique TiO2(B) structures, especially those with complex configurations remains a great challenge. This work presents a completely new synthetic approach for fabricating hierarchical nanoporous TiO2(B) assemblies with tailored crystallites and architectures via the reaction between tetrabutyl titanate and normal fatty acids. Three different kinds of normal fatty acids, i.e., pentanoic acid, hexanoic acid, and nonanoic acid were utilized as the sole solvent. After a simple solvothermal treatment, nanoporous TiO2(B) microspheres constructed by [001]-elongated ultrathin nanorods, randomly aggregated ultrafine nanocrystals, and crystallographically oriented nanocrystals were successfully produced separately. Further investigation revealed that the morphology of the hierarchical assemblies could be modified by using foreign substrates to adjust the growth dynamics of TiO2(B) crystals. As a good illustration, by introducing graphene nanosheets into the tetrabutyl titanate-pentanoic acid system, nanosized [001]-elongated-ultrathin-nanorod-constructed nanoporous TiO2(B) assemblies were obtained, which exhibited superior performance as an anode in Li-ion batteries. This work can not only shed new light on TiO2(B) crystallization, but also provide an effective solution for the rational design of complex TiO2(B) micro-/nanoarchitectures for desired applications.

A unique black TiO2 created from CO-induced oxidation of defect-rich TiO2

Black TiO2 is an emerging semiconductor with a narrowed band gap for visible light absorption. Very recently, CO, as a reductant, was explored as a substitute of H2 to prepare black TiO2. In this work, we surprisedly found that CO could act as an oxidant to remediate the oxygen vacancies in defect-rich TiO2, accompanied with the introduction of carbon species into it, leading to the formation of a unique black TiO2 material. The light absorption of this material was significantly enhanced with an evidently narrowed band gap down to 2.79 eV. Furthermore, a mid-gap state emerged owing to the carbon species. These findings highlight a successful exploration in both black TiO2 synthesis and the application of CO as an oxidant.

Enhanced mechanisms of electrocatalytic-ozonation of ibuprofen using a TiO2 nanoflower-coated porous titanium gas diffuser anode: Role of TiO2 catalysts and electrochemical action in reactive oxygen species formation

This study aims to systematically investigate the enhanced mechanism of our previously proposed novel electro-heterogeneous catalytic ozonation (E-catazone) process. In this process, a unique TiO2 nanoflower (TiO2-NF)-coated porous titanium gas diffuser served as the anode and aerator at same time, and commercial graphite-coated Ti mesh (Graphite @Ti mesh) acted as cathode. For ibuprofen (kibuprofen,O3 of 9.6 M−1 s−1), an ozone-resistant pharmaceutical micro-pollutant, as the model-pollutant, E-catazone with the TiO2-NF anode showed excellent performance and significant synergistic effect for ibuprofen destruction efficiency and rate, and also delivered much higher enhancement ratios of 7.9 and 6.8 for ibuprofen degradation and TOC removal, respectively. The study revealed that OH is the main reactive oxygen species in the degradation of ibuprofen, and that the OH production was largely increased in E-catazone, by approximately two orders of magnitude of that in the ozonation and EO (electrochemical oxidation) processes. Further, TiO2-NF and electrochemical action were found to play crucial roles in promoting O3 conversion for enabling the enhanced formation of OH. Surprisingly, we found that the presence of the anode catalyst, TiO2-NF, can improve the electro-generation of H2O2 by decreasing cathodic potential, while the electrochemical action can also significantly enhance anodic TiO2-NF interface adsorption and conversion of O3. The results of computational studies showed that TiO2-(OH)2 is the main site for O3 adsorption at anodes, and the application of positive overpotential or coating of TiO2-NF at the anode can significantly improve the interfacial adsorption of O3. Therefore, E-catazone has great potential for synchronously and effectively promoting heterogeneous and homogeneous catalytic reactions of ozone under the synergistic action of TiO2-NF and electrochemical action, and shows broad prospects in application for the efficient degradation of pharmaceutical micro-pollutants.

Hierarchical flower-like TiO2 microspheres with improved dye-sensitized solar cell performance

Hierarchical flower-like TiO2 microspheres (FMS) and TiO2 nanorice (NR) were obtained, respectively, by controlling the dosage of Ti precursor via a simple hydrothermal process. Flower-like TiO2 microspheres consist of nanopetals grown from the center radially, the nanopetals are about several nm in average thickness, and each nanopetal has a thinned tip with an average size of 15 nm. The unique hierarchical TiO2 microspheres with large surface area (118.6 m2 g−1) suggested its potential application in dye-sensitized solar cells (DSSCs). The power conversion efficiency of FMS-based DSSCs (9.58%) is much higher than that of NR-based DSSCs (7.13%), which could be ascribed to its excellent light-scattering and dye absorption ability, shorter electron transport pathway and longer electron recombination time derived from the thin thickness and large specific surface area of nanopetals.

Atomic Layer Deposition Coating of TiO2 Nano-Thin Films on Magnesium-Zinc Alloys to Enhance Cytocompatibility for Bioresorbable Vascular Stents.

Background and purposeA coronary stent is a well-known cardiovascular medical device implanted to resolve disorders of the circulatory system due to bloodstream narrowing. Since the implanted device interacts with surrounding biological environments, the surface properties of a typical implantable stent play a critical role in its success or failure. Endothelial cell adhesion and proliferation are fundamental criteria needed for the success of a medical device. Metallic coronary stents are commonly used as biomaterial platforms in cardiovascular implants. As a new generation of coronary stents, bioresorbable vascular scaffolds have attracted a great deal of attention among researchers and studies on bioresorbable materials (such as magnesium and zinc) remain a target for further optimization. However, additional surface modification is needed to control the biodegradation of the implant material while promoting biological reactions without the use of drug elution.MethodsHerein, precise temperature and thickness controlled atomic layer deposition (ALD) was utilized to provide a unique and conformal nanoscale TiO2 coating on a customized magnesium-zinc stent alloy.ResultsImpressively, results indicated that this TiO2 nano-thin film coating stimulated coronary arterial endothelial cell adhesion and proliferation with additional features acting as a protective barrier. Data revealed that both surface morphology and surface hydrophilicity contributed to the success of the ALD nanoscale coating, which further acted as a protection layer inhibiting the release of harmful degradation products from the magnesium-zinc stent.ConclusionOverall, the outcome of this in vitro study provided a promising ALD stent coating with unique nano-structural surface properties for increased endothelialization, and as a result, ALD should be further studied for numerous biomedical applications.

Rutile TiO2 supported single atom Au catalyst: A facile approach to enhance methanol dehydrogenation

Rutile TiO2 supported single atom Au catalyst for promoting methanol dehydrogenation activity in direct methanol fuel cell (DMFC) has been investigated by using density functional theory calculations. Rutile Au1/TiO2 (110) and non-doped rutile TiO2 (110) surfaces are conducted due to their lowest index and energy. Fruitfully, rutile Au1/TiO2 (110) surface exhibits the excellent catalytic performance on methanol dehydrogenation, being prone to reform under alkali conditions; its lattice gold, titanium and oxygen atoms are involved in the whole methanol dehydrogenation process, along with the intermediate adsorbates. Methanol, via the activation of OH and C–H bonds on rutile Au1/TiO2 (110) surface, proceeds the subsequent stripping of the possible intermediate products: H2, HCHO, CO and CO2 to gas phase separately. Despite the most difficult step among them, CO2 stripping benefits considerably from the unique rutile TiO2 (110) surface and alkali participation.

A wear-resistant TiO2 nanoceramic coating on titanium implants for visible-light photocatalytic removal of organic residues

An effective treatment for peri-implantitis is to completely remove all the bacterial deposits from the contaminated implants, especially the organic residues, to regain biocompatibility and re-osseointegration, but none of the conventional decontamination treatments has achieve this goal. The photocatalytic activity of TiO2 coating on titanium implants to degrade organic contaminants has attracted researchers’ attention recently. But a pure TiO2 coating only responses to harmful ultraviolet light. Additionally, the poor coating mechanical properties are unable to protect the coating integrity versus initial mechanical decontamination. To address these issues, a unique TiO2 nanoceramic coating was fabricated on titanium substrates through an innovative plasma electrolytic oxidation (PEO) based procedure, which showed a disordered layer with oxygen vacancies on the outmost part. As a result, the coating could decompose methylene blue, rhodamine B, and pre-adsorbed lipopolysaccharide (LPS) under visible light. Additionally, the coating showed two-fold higher hardness than untreated titanium and excellent wear resistance against steel decontamination instruments, which could be attributed to the specific micro-structure, including the densely packed nanocrystals and good metallurgical combination. Moreover, the in vitro response of MG63 cells confirmed that the coating had comparable biocompatibility and osteoconductivity to untreated titanium substrates. This study provides a unique coating technique as well as a photocatalytic cleaning strategy to enhance decontamination of titanium dental implants, which will favour the development of peri-implantitis treatments. Statement of SignificanceThe treatment of peri-implantitis is based on the complete removal of bacterial deposits, especially the organic residues, but conventional decontamination treatments are hard to achieve it. The photocatalytic activity of TiO2 coating on titanium implants to degrade organic contaminants provides a promising strategy for deeper decontamination, but its nonactivation to visible light and poor mechanical properties have limited its application. To address these issues, a unique TiO2 nanoceramic coating was fabricated on titanium substrates based on plasma electrolytic oxidation. The coating showed enhanced visible-light photocatalytic activity, excellent wear resistance and satisfied biocompatibility. Based on this functional coating, it is promising to develop a more efficient strategy for deep decontamination of implant surface, which will favour the development of peri-implantitis treatments.

TiO2@TiO2−xHx core-shell nanoparticle film/Si heterojunction for ultrahigh detectivity and sensitivity broadband photodetector

A simple hydrogenation treatment is used to synthesize unique oxygen-deficient TiO2 with a core/shell structure (TiO2@TiO2−xHx), superior to the high H2-pressure process (under 20 bar for five days). It is demonstrated that oxygen-deficient TiO2 nanoparticle film/Si heterojunction possesses improved photoresponse performance compared to the untreated TiO2 nanoparticle film/Si heterojunction. Particularly, under 900 nm of 0.5 μW cm−2, the oxygen-deficient TiO2 nanoparticle film (TiO2@TiO2−xHx core–shell nanoparticle film)/Si heterojunction shows high responsivity (R) of 336 A W−1, prominent sensitivity (S) of 1.3 × 107 cm2 W−1, accompanied with a fast rise and decay time of 6 and 5 ms, respectively. Significantly, the detectivity (D*) of the photodetector is up to 1.17 × 1014 cm Hz1/2 W−1, which is better than that reported in metal oxide nanomaterials/Si heterojunction photodetectors, and is 4–5 orders of magnitude higher than some 2D nanosheets/Si heterojunctions of 109–1010 cm Hz1/2 W−1, indicating the excellent ability to detect weak signals. The oxygen vacancies generated in amorphous shell TiO2−xHx make the Fermi level of TiO2−x shift near the conduction band minimum and can lead to reduced dark current. The high absorption and reduced dark current of the heterojunction ensure excellent photoresponse properties of oxygen-deficient TiO2 nanoparticle film/Si heterojunction. The H-reduced oxygen-deficient amorphous shell may be an excellent candidate to enhance the photoresponse performance of metal oxide/Si heterojunction.

Mesoporous black TiO2 array employing sputtered Au cocatalyst exhibiting efficient charge separation and high H2 evolution activity

The separation and transfer of photogenerated carriers are the key issue in the design of high performance TiO2 photocatalysts. In order to overcome the kinetic limitations and achieve rapid charge transfer, TiO2-related multi-component catalysts have been extensively studied. Among all the TiO2 supports, the impressive black TiO2 (BT) with broad visible light absorption spectrum and oxygen vacancies are preferable, but still suffers from low quantum efficiency. Meanwhile, poor control of cocatalyst placement by conventional loading method can also severely impede photocatalytic efficiency. Herein a fast and simple metal magnetron sputter approach was used to place highly-uniformed Au nanoparticles cocatalyst on the top of the mesoporous TiO2–BT nanotube array fabricated by in situ electrochemical anodization approach on a Ti film. This confined plasmonic photocatalyst with highly uniformly distributed Au cocatalysts exhibited greatly enhanced charge-separation and charge-transfer behavior, and a remarkable 10 times enhancement of the photocatalytic H2 evolution reactivity over conventional TiO2 nanotube. The TiO2-BT-Au electron transfer cascade structure is proposed in which black TiO2 acts as a buffer layer for TiO2 conduction band electrons, allowing efficient photogenerated electrons to be transferred to Au nanoparticles and then into the TiO2 pores that suitable for H2 generation. Since the nanotube walls themselves are curved upwards, the short diffusion length allows electrons to be easily transferred to the cocatalyst, where recombination of photogenerated electron pairs is limited. The metal magnetron sputter technique for noble metal cocatalyst immobilization and the unique TiO2–BT–Au electron-transfer system are promising and can be extended to the design of other supported catalysts.

Mesocrystalline anatase nanoparticles synthesized using a simple hydrothermal approach with enhanced light harvesting for gas-phase reaction.

Mesocrystalline TiO2 nanoparticles were synthesized using a hydrothermal approach. A simple two-step procedure at low temperature (<140 °C) allowed the nucleation of primary particles sized 2-4 nm and their subsequent assembly as almost spherical aggregates sized ≈20 nm. X-ray powder diffraction (XRD), Raman and X-ray photoelectron spectroscopy (XPS) studies, and HRTEM studies confirmed anatase as the unique TiO2 crystalline phase. The mesocrystalline structure of the anatase aggregates was clearly evidenced by HRTEM and SAED results. The mesocrystalline nanopowders exhibit a mesoporous structure with a surface area and pore volume of 63.5 m2 g-1 and 0.22 cm3 g-1, respectively. Ultraviolet (UV) and visible light (Vis) absorption ability were recorded. The combined high effectiveness and selectivity for the NOx abatement of the new mesocrystalline photocatalyst are reported. It is worth remarking that the maximised selectivity values reached for the NOx process are reported for the first time and could be associated with the mesoporous nature of the anatase photocatalyst.

Atomic layer deposition of nano-TiO2 thin films with enhanced biocompatibility and antimicrobial activity for orthopedic implants.

Titanium (Ti) and its alloys have been extensively used as implant materials in orthopedic applications. Nevertheless, implants may fail due to a lack of osseointegration and/or infection. The aim of this in vitro study was to endow an implant surface with favorable biological properties by the dual modification of surface chemistry and nanostructured topography. The application of a nanostructured titanium dioxide (TiO2) coating on Ti-based implants has been proposed as a potential way to enhance tissue-implant interactions while inhibiting bacterial colonization simultaneously due to its chemical stability, biocompatibility, and antimicrobial properties. In this paper, temperature-controlled atomic layer deposition (ALD) was introduced for the first time to provide unique nanostructured TiO2 coatings on Ti substrates. The effect of nano-TiO2 coatings with different morphology and structure on human osteoblast and fibroblast functions and bacterial activities was investigated. In vitro results indicated that the TiO2 coating stimulated osteoblast adhesion and proliferation while suppressing fibroblast adhesion and proliferation compared to uncoated materials. In addition, the introduction of nano-TiO2 coatings was shown to inhibit gram-positive bacteria (Staphylococcus aureus), gram-negative bacteria (Escherichia coli), and antibiotic-resistant bacteria (methicillin-resistant Staphylococcus aureus), all without resorting to the use of antibiotics. Our results suggest that the increase in nanoscale roughness and greater surface hydrophilicity (surface energy) together could contribute to increased protein adsorption selectively, which may affect the cellular and bacterial activities. It was found that ALD-grown TiO2-coated samples with a moderate surface energy at 38.79 mJ/m2 showed relatively promising antibacterial properties and desirable cellular functions. The ALD technique provides a novel and effective strategy to produce TiO2 coatings with delicate control of surface nanotopography and surface energy to enhance the interfacial biocompatibility and mitigate bacterial infection, and could potentially be used for improving numerous orthopedic implants.

Synthesis of highly dispersed and versatile anatase TiO2 nanocrystals on graphene sheets with enhanced photocatalytic performance for dye degradation

A highly dispersed and versatile anatase TiO2 nanocrystal on graphene sheets (TiO2–G) was synthesized by a simple solvent thermal method. The structural and optical properties of the as-synthesized samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV–Vis absorption spectroscopy and Raman spectra. The results show that the anatase TiO2 nanocrystals with approximately 20–30 nm size are well distributed on the graphene sheets, and the introduction of graphene increases the light absorption intensity in visible light region. Noticeably, the TiO2–G exhibits excellent photocatalytic activity and reusability, and can be applied to the degradation of various organic dyes, such as methyl orange (MO), methyl blue (MB) and rhodamine-B (RhB). This unique TiO2–G composite photocatalyst proved to have great potentials for organic contaminants degradation in wastewater.

Hierarchical TiO2 Structures Derived from F− Mediated Oriented Assembly as Triple-functional Photoanode Material for Improved Performances in CdS/CdSe Sensitized Solar Cells

A facile solvothermal method was adopted to prepare unique hierarchical TiO2 structures which are assembled from single-crystal tubes and inflated with oriented aligned nanoparticles. A F− mediated anisotropic assembling mechanism was proposed based on time dependent experiments and density function theory calculation. Hydrofluoric acid was found to play crucial roles on the nucleation, growth and assembling stages and hierarchical TiO2 structures consisted of solid and hollow branches could be selectively prepared via simply altering the hydrofluoric acid dosages. The as-prepared hierarchical TiO2 structures were employed as triple-functional photoanode material to boost the performances of CdS/CdSe sensitized solar cells. The hexagonal tubes with well-defined crystal facets exhibited high light-reflection rate for the incident light. Meanwhile, the inflated nanoparticles offered high accessible surface area of ∼71m2g−1, and the oriented aligned structures minimized the inter-particles defects to suppress the undesired charge recombination. Due to these structural qualities, the light harvesting efficiency and electron life time were substantially enhanced, which leads to a power conversion efficiency of 4.9%, representing a ∼40% improvement compared with nanoparticle based device (3.5%).

The involvement of coordinative interactions in the binding of dihydrolipoamide dehydrogenase to titanium dioxide-Localization of a putative binding site.

Titanium (Ti) and its alloys are widely used in orthodontic and orthopedic implants by virtue to their high biocompatibility, mechanical strength, and high resistance to corrosion. Biointegration of the implants with the tissue requires strong interactions, which involve biological molecules, proteins in particular, with metal oxide surfaces. An exocellular high-affinity titanium dioxide (TiO2 )-binding protein (TiBP), purified from Rhodococcus ruber, has been previously studied in our lab. This protein was shown to be homologous with the orthologous cytoplasmic rhodococcal dihydrolipoamide dehydrogenase (rhDLDH). We have found that rhDLDH and its human homolog (hDLDH) share the TiO2 -binding capabilities with TiBP. Intrigued by the unique TiO2 -binding properties of hDLDH, we anticipated that it may serve as a molecular bridge between Ti-based medical structures and human tissues. The objective of the current study was to locate the region and the amino acids of the protein that mediate the protein-TiO2 surface interaction. We demonstrated the role of acidic amino acids in the nonelectrostatic enzyme/dioxide interactions at neutral pH. The observation that the interaction of DLDH with various metal oxides is independent of their isoelectric values strengthens this notion. DLDH does not lose its enzymatic activity upon binding to TiO2 , indicating that neither the enzyme undergoes major conformational changes nor the TiO2 binding site is blocked. Docking predictions suggest that both rhDLDH and hDLDH bind TiO2 through similar regions located far from the active site and the dimerization sites. The putative TiO2 -binding regions of both the bacterial and human enzymes were found to contain a CHED (Cys, His, Glu, Asp) motif, which has been shown to participate in metal-binding sites in proteins.