Formation Of Nanorods Research Articles

Synthesis and growth mechanism of ZnO nanocandles using thermal evaporation and their efficient CO sensing performance

We report on the single step grown ZnO nanocandles without adding any catalyst for efficient CO gas sensing application. A simple, scalable, and cost-effective thermal evaporation technique was employed for the growth of ZnO nanostructures on alumina substrate at 600 °C. It was observed that oxygen ambient (variation in oxygen flow rates from 20 to 40 sccm) strongly influences the shape and size of the ZnO nanostructures (i.e., the formation of nanocandles or nanorods). The as grown ZnO nanostructures were characterized using various techniques such as X-ray diffraction, Field emission scanning electron microscopy, photoluminescence, and X-ray photoelectron spectroscopy. Further, a comprehensive analysis of the CO gas sensing performance of each sample was recorded under various conditions, and the corresponding mechanism was reported. We have achieved the maximum sensor response (SR%) ∼ 78.3% along with a response/recovery time ∼ 59.5 s/109.4 s towards 91 ppm of CO gas at 400 °C for the sample synthesized at 40 sccm oxygen gas flow rate (i.e., for nanocandles). While, a relatively lower SR ∼ 70.1% and ∼ 64.1% and higher response/recovery time of ∼ 77.8 s/118.6 s and ∼ 84.6 s/122.1 s were obtained for the samples synthesized at 30 sccm and 20 sccm, respectively (i.e., for nanorods). Moreover, the calculated detection limit for ZnO nanocandles was 110 ppb. The selectivity test shows that the ZnO nanocandles are highly responsive to CO gas and exhibits long term stability (tested over 360 days). Thus, ZnO nanocandles can be used for the fabrication of robust CO gas sensors.

Synergistic enhancement of photocatalytic and antimicrobial efficacy of nitrogen and erbium co-doped ZnO nanoparticles

Using the chemical co-precipitation approach, a series of nitrogen (N) and erbium (Er) co-doped ZnO nanoparticles (NPs) was effectively synthesized to enhance the photocatalytic and antibacterial activities. Several characterization techniques, including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), UV-vis, and photoluminescence (PL) spectroscopy, were carried out to validate the evaluated photocatalytic and antibacterial activities. XRD analysis confirms the pure wurtzite ZnO phase without the presence of any secondary phase. XPS analysis confirms the successful incorporation of nitrogen and erbium into the ZnO matrix. The optical bandgap of ZnO calculated from UV-vis spectroscopy shows a redshift after Er–N co-doping, with the lowest bandgap of 3.215 eV calculated for Zn0.97Er0.03N0.01O0.99 NPs. SEM images demonstrate the formation of nanorods after N–Er co-doping, followed by gradually increased rod diameter and length after N–Er co-doping. Moreover, the photocatalytic activities of ZnO samples were measured by their ability to facilitate the photodegradation of Rhodamine B under UV irradiation. ZnO with 1 mol% N doping exhibits 88% photodegradation of RhB under UV light within 360 min, and the photodegradation and antibacterial activity are greatly improved with Er co-doping. In fact, 3 mol% Er-1 mol% N doped ZnO NPs demonstrate the highest photocatalytic activity, with approximately 96% degradation after 360 min, as well as superior antibacterial activity against Staphylococcus aureus (Gram-positive bacteria) and Pseudomonas aeruginosa (Gram-negative bacteria) with the highest zone of inhibition (ZOI) of 16 nm, due to nanorod formation, increased reactive oxygen species (ROS), and decreased electron–hole recombination, as validated by SEM, XPS, and PL spectroscopy.

VOCs sensing properties of samarium oxide nanorods

Samarium oxide (Sm2O3) nanorods were prepared by a facile hydrothermal route using cetyl trimethyl ammonium bromide (CTAB) as an organic surfactant. The structural and morphological characteristics of the synthesized nanorods were studied by different techniques including FESEM, XRD, EDS, and FTIR. The results showed the formation of Sm2O3 nanorods made of a single cubic crystalline phase. Sm2O3 nanorods were investigated for the development of conductometric sensors for the indoor air quality (IAQ) assessment. For this scope, the sensing properties of Sm2O3 nanorods towards some representative volatile organic compounds (VOCs) present in the indoor environment, such as acetone, ethanol and formaldehyde, were evaluated. The investigation of Sm2O3 nanorods sensing properties towards low ppm of acetone revealed good sensitivity and selectivity than ethanol and formaldehyde. At an operating temperature of 250 °C, the response to 1 ppm of acetone was 3.41 (Rgas/Rair) with a relatively fast response and recovery times of 125 and 43 s, respectively. The good performances registered allow to propose the developed device as an acetone sensor for IAQ assessment.

Morphological evaluation and boosted photocatalytic activity of N-doped ZnO nanoparticles prepared via Co-precipitation method

Pristine and nitrogen (N) doped zinc oxide (ZnNxO1-x, x = 0, 0.005, 0.01, and 0.02) nanoparticles (NPs) were successfully synthesized using chemical co-precipitation approach. The formation of pure crystalline wurtzite ZnO phase without any second phase during N-doping was confirmed by X-ray diffraction (XRD) analysis of N-doped ZnO samples. X-ray photoelectron spectroscopic (XPS) analysis ensured the effective inclusion of nitrogen into ZnO matrix. The morphological analysis revealed the formation of nanorods as a result of N-doping. The optical band gap calculated from UV–vis spectroscopy was observed to decrease up to 1 mol.% N doping followed by a subtle increase. Photoluminescence (PL) spectra revealed that electron-hole recombination was the least for 1 mol.% N doped ZnO NPs. ZnN0.01O0.99 NPs showed superior photocatalytic activity among all samples due to rod-shaped NPs and reduced electron-hole recombination, which was accessed by the photodegradation of Rhodamine B (RhB).

Intriguing and Facile Preparation Approach of CdO Nanorod-Based Abundant Chitosan for Symmetric Supercapacitors.

Abundant chitosan was rationally used for the green fabrication of cadmium oxide nanorods (CdO nanorods) owing to its environmentally benign characteristics, bioavailability, low cost, etc. However, the primary unsubstituted amino group of chitosan interacts with the surface of Cd salt at higher temperatures, resulting in CdO nanorod formation. A one-step hydrothermal technique was adopted in the presence of chitosan. Optical, structural, and morphology techniques characterized CdO nanorods. According to X-ray diffraction crystallography, CdO is well crystallized in the face-centered cubic lattice with an Fm-3m (225) space group. The AC@CdO nanoelectrode demonstrated an outstanding gravimetric capacitance of 320 F g-1 at a current density of 0.5 A g-1, nearly three-fold that of ordinary AC electrodes. The AC electrode and the AC@CdO nanoelectrode retain 90 and 93% of their initial specific capacitance after 10,000 galvanostatic charge discharge cycles. The AC@CdO nanoelectrode has a lower equivalent series resistance value than the AC electrode. Moreover, AC@CdO symmetric supercapacitor devices achieve excellent results in terms of specific energy, specific power, and capacitance retention.

Curcumin-capped gold nanorods as optical sensing platform for sequence specific detection of DNA based on their self-assembly

We are reporting curcumin-induced gold nanorods as an optical sensing platform for the detection of sequence-specific DNA target through their self-assembly. The combined effect of eco-friendly reducing agent (i.e., curcumin) and silver nitrate in a basic medium (i.e., pH 10) has been attributed for the formation of small gold nanorods (AuNRs) having approximate length and diameter i.e., 19.7 ± 0.8 nm and 6.0 ± 0.5 nm, respectively, and lower longitudinal surface plasmon resonance (SPR) enable to detect and analyse different biomarkers. Further, for evaluating cellular uptake of as-synthesized AuNRs, the cytotoxicity study has been carried out by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay on A549 cells and HEPG2 cell lines, respectively, and shown approximately similar cytotoxicity. Interestingly, as-synthesized optically and electronically active AuNRs based nanobiosensing platform enable to detect sequence-specific DNA targets with low level of detection limit i.e., LOD 8.6 ± 0.15 pM for complimentary target (CT) DNA with higher sensitivity and better selectivity. Finally, this study is suggesting a simplistic bio-mediated approach of tuning the shape and size of AuNRs for sensitive, selective and reliable nanobiosensing platform for sequence-specific DNA detection related to cancer cells.

Engineering the photo-induced charge generation between TiO2 and FeS2 heterojunction for enhanced photocatalytic wastewater purification

Wastewater treatment using photocatalytic processes is an eco-friendly approach to tackle the scarcity of drinkable water. In this study, a heterojunction of TiO2 and FeS2 nanostructures was synthesized via a one-pot polyol method, and their activity was investigated in eliminating crystal violet as a dye pollutant. The difference in the thermodynamic stability of iron and titanium oxides in polyol solution containing thiourea led to the formation of TiO2 nanorods and sulfurization of iron in the form of FeS2 nanospheres. Incorporating TiO2 nanorods with FeS2 chalcogenide nanostructures narrowed the band gap energy (from 3.05 to 2.6 eV) and enhanced the photo-induced charge carriers’ separation by forming an internal electric field. Compared to TiO2 nanorods, the synthesized heterojunction photocatalyst using 0.5 ml TBOT (FST-0.5) exhibited the best activity and increased crystal violet degradation from 55% to 89%. The optimization and modeling of the interaction between operating parameters were performed by response surface methodology based on central composite design. The statistically significant quadratic polynomial model was best for fitting the experimental data. Regarding this model, adjusting the catalyst weight, pollutant concentration, and solution pH at an optimum amount of 0.015 g, 4 ppm, and 9 causes the highest photocatalytic degradation, around 94%. The kinetics studies also revealed that photocatalytic degradation follows first-order kinetics with an apparent rate constant of 0.0184 min−1. The contribution of active species was determined by free-radical capture experiment. Herein, photo-holes had the main contribution (38.3%), and the rest accounted for hydroxide radicals (26.6%), superoxide anions (11.7%), and electrons (23.4%).

Synthesis of Ta2O5 by introducing graphene quantum dot with excellent photocatalytic performance for degradation of tetracycline

Wide band gap, weak adsorption ability, poor electronic conductivity and insufficient charge transportation limit the applications of Ta2O5 in photodegradation of antibiotics. The paper reports synthesis of Ta2O5 photocatalyst by introducing glycine-functionalized graphene quantum dot (GGQD). The introduction of GGQD effectively prevents the hydrolysis of Ta(V) and finally leads to the formation of small Ta2O5 nanorods. The modification of graphene sheets on the Ta2O5 surface enhances the adsorption towards tetracycline. The presence of Ta4+ self-doped oxygen vacancy narrows the band gap of Ta2O5, optimizes the band position and creates new defect energy level. These improve the light absorption capacity to visible light and promotes the photogenerated charge transfer. The graphene as electron trap suppresses the recombination of photogenerated charge carriers. The graphene as light sensitizer expands the absorption to visible light. The synergy of these multiple structure engineering realizes an excellent photocatalytic performance of Ta2O5 for solar-light driven tetracycline photodegradation. The photodegradation efficiency of 60 min solar-light irradiation is 6.6 times higher, apparent kinetic constant is 19.3 times higher and photocurrent density is 13.4 times over Ta2O5. The study also paves an avenue for construction of metal nanomaterials with desirable photoelectric properties in catalysis, energy storage and conversion and sensing.

Non-contact approach to extract Schottky barrier characteristics for gas sensitive nanostructured interfaces

Formation of high precision nanorod based surface morphologies can be engineered with nanotechnology to mimic the function of sensory hairs. Gas sensitive I-V characteristics unique to these surfaces require initialisation under voltage bias and temperature elevation to exploit their band structures and therefore achieve optimal gas response. Prior to detection, devising effective approaches to optimise nanorod based sensors can provide access and efficient control to downsize and significantly miniaturise current gas sensors. In this work, we devised a novel non-contact analysis approach via ultraviolet photoelectron spectroscopy (UPS) to extract specific band structure parameters specifically to locate particular bias for optimal sensor initialisation. The results from five cases all indicate how fabricated nanostructured Schottky barrier heights can be evaluated from UPS data and how their I-V data are correlated and also validate our band structure postulations. The obtained Schottky barrier height values from simulated band structures provided an optimal biasing condition of 0.8 V for Au-ZnO nanorod hydrogen gas sensory operation at 150 °C, demonstrating experimental validity with gas-electrical measurements. Further, the gas response data show exponential dependence with gas concentration which is highly relevant for programmable trigger response controlled sensing function based applications.

α-Fe2O3/CeO2 S-scheme heterojunction photocatalyst for enhanced photocatalytic H2 evolution

High photo-stability and effective charge separation are pivotal for hydrogen production over the photocatalysts through solar energy. Here mesoporous CeO2 nanorods were hydrothermally synthesized using cetyltrimethyl ammonium bromide and tetrapropylammonium hydroxide as the template to construct the novel S-scheme heterojunction α-Fe2O3/CeO2 photocatalyst. The obtained heterojunction Fe2O3/CeO2 photocatalyst exhibited outstanding enhanced H2 evolution under visible illumination. The XRD results indicated that the Fe2O3/CeO2 nanocomposites revealed rhombohedral α-Fe2O3 and cubic CeO2 structures without impurities. TEM images revealed the formation of CeO2 nanorods with 400 nm length and 20 nm width decorated with Fe2O3 NPs (10 nm). The optimized S-scheme Fe2O3/CeO2 nanocomposites displayed a superior photocatalytic H2 evolution rate of 2973.2 µmolg−1h−1, which was promoted 5.43 folds greater than that of CeO2 nanorods (547.05 µmolg−1h−1). The electron transport channels in S-scheme Fe2O3/CeO2 nanocomposites interfacial junctions facilitated the directional migration spatial and separation of photocarriers. The H2 evolution rate over the obtained Fe2O3/CeO2 photocatalyst was significantly promoted due to its synergistic effect, porous architecture, oxygen vacancies, small particle size and high visible light absorption ability. There was no decrease in the H2 evolution rate after five cycles of photocatalytic H2 evolution, which could verify the durability and stability of the Fe2O3/CeO2 nanocomposite. The photoluminescence (PL) and electrophotochemical responses were conducted to determine the charge carriers separation rate and understand the photocatalytic mechanism.

Investigating the effect of aligned Ag nanorods on para-aramid woven fabric and anisotropy in inter-yarn friction

Inter yarn friction, measured in terms of yarn pull-out force, is a major mechanism of energy absorption in soft body armor. Increasing inter-yarn friction of para-aramid fabric to improve ballistic performance without adding weight is challenging. This work reports the fabrication of aligned Ag nanorods (AgNRs) on the para-aramid (Kevlar) fabric surface using the glancing angle deposition technique. A single yarn pull-out test examines Kevlar fabric treatment. The AgNRs-coated para-aramid fabric retains its flexibility and weight while increasing yarn pull-out force by 130%. Anisotropy in inter-yarn friction depends on the yarn's sliding direction relative to Ag nanorod tilt direction, indicating direction-dependent yarn pull-out force. The periodic character of pull-out response post-peak force is replicated by modeling the yarn pull-out phenomenon by incorporating a mesoscale level numerical model of woven fabric. The numerical model confirms the experimental results that formation of nanorods significantly increases inter-yarn friction and pull-out force.

Bifunctional strontium-doped barium oxide nanorods as promising photocatalysts and electrodes for energy storage applications

It is critical to design highly efficient, clean, and renewable energy sources to replace fossil fuels and mitigate their harmful impacts on the environment. Two effective approaches for replacing fossil fuels are electrochemical energy storage devices and photocatalysis. Herein, for the first time, strontium-doped barium oxide nanorods (Sr-BaO NRs) were synthesized using a facile co-precipitation technique and characterized with different analytical techniques to explore their physical, electrochemical, and photocatalytic properties. The successful formation of Sr-BaO NRs and their structural variations were confirmed by XRD, Raman, and FT-IR results. UV–Vis analysis showed that the bandgap of BaO was decreased by increasing the Sr concentration. SEM micrographs confirmed the formation of nanorods. The findings of the photocatalytic experiments showed excellent photodegradation efficiencies against methylene blue (MB) (95.55 %), methyl orange (MO) (98 %), and rhodamine-B (RhB) (96.33 %) dyes after 60, 70, and 90 min, respectively under UV light irradiation. Higher stability up to five cycles was shown in the recyclability experiments employing the optimized catalyst. The electrochemical properties of Sr-BaO NRs were also studied for the first time. 4 % Sr-BaO NRs offered an exceptional specific capacitance of 925.2 F/g, and a good energy density of 32.12 Wh/Kg with a higher power density of 750 W/kg at a current density of 3 A/g. The development of such affordable and efficient photocatalysts and electrode materials is desired for future environment protection and energy storage applications.

Effect of Zinc Nitrate Concentration on the Morphology of ZnO Nanostructures Grown by Hydrothermal Method

Herein, the influence of the precursor concentration on the morphology of zinc oxide (ZnO) nanostructures prepared via hydrothermal process using zinc nitrate salt with varied concentrations (from 0.01 to 0.15 m) is investigated. Scanning electron microscopy (SEM), UV–vis transmittance, photoluminescence, and X‐ray diffraction are used to characterize the synthetized nanostructures. It is revealed in the obtained results that the salt concentration is a key parameter that controls the ZnO nanostructure. It is concluded that a low salt concentration (0.01 and 0.05 m) leads to the formation of ZnO nanorods while increasing the salt concentration (from 0.1 to 0.15 m) leads to the formation of nanosheets mixed with nanorods‐ and nanosheets‐like morphology. The ZnO nanostructures growth mechanism is discussed.

Structural properties of lithium doped V3O8 nanorods synthesized by hydrothermal method

The structural properties of lithium-doped trivanadate(Li-doped-V3O8)nanorods have been prepared by using vanadium pentoxide xerogelas reducing agent via hydrothermal method of lithium nitrate in the presence of excess sodium hydroxide. The resulting Li doped V3O8 nanorods materials were characterised using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), and William- hall plot analysis. Spectroscopic results indicated the successful formation of lithium-doped V3O8 nanorods. The surface morphologies of lithium-doped V3O8 nanorods were obtained to be dependent on the molar ratio of lithium nitrate to vanadium pentoxide. As obtained, nanorods have a particle size in the range of 22.5 nm and 27 nm. The SEM images of vanadium dioxide and Li doped V3O8 reveal the nanorods to have dimensions on the order of 2–4 µm and 1–2 µm in length and 20–30 nm in diameter. The EDX diffraction measures the elemental composition of nanorods. The XRD studies confirm the formation of the compound and crystallinity structure of nanomaterials VO2 and Li doped V3O8. By the Williamson-Hall plot, which displays the structural flaws of nanomaterials, the strain is measured. The unique properties of these Li doped V3O8 make them attractive use in lithium-ion batteries (LIBs) application.

Studies on Catalytic and in Vitro Cytotoxicity Effects of ZnO Nanorods Containing Ag and Their Structural, Morphological, and Antimicrobial Properties

Zinc oxide (ZnO) and Ag-doped ZnO nanoparticles were synthesized using a soft chemical route, and their properties were characterized using various techniques, including X-ray diffraction (XRD), high-resolution scanning electron microscope (HRSEM), energy dispersive X-ray diffraction spectroscopy (EDS), and high-resolution transmission electron microscope (HRTEM). The ZnO (Ag[Formula: see text]Zn[Formula: see text]O (where [Formula: see text], 0.02 and 0.03) exhibited a hexagonal Wurtzite structure, and Ag doping resulted in the formation of nanorods with decreased grain size. The synthesized materials were found to have antimicrobial properties against human pathogenic bacteria and fungi. MTT assays showed that Ag-doped ZnO had higher cytotoxicity against human embryonic kidney cancer cell lines (HEK 293) compared to pure ZnO. The samples also demonstrated active activity towards the catalyst for the selective oxidation of alcohols. Finally, a statistical model was developed for antibacterial studies using ANOVA, which was consistent with the experimental findings. These results demonstrate the potential of Ag-doped ZnO nanoparticles for use in biomedical and catalytic applications.

Controllable fabrication of Bi4Ti3O12/C/Bi2S3/MoS2 heterojunction with effective suppression of Bi2S3 assisted by amorphous carbon interlayer for significantly enhanced photocatalysis

BackgroundFabricating heterojunctions by combining with MoS2 is efficient to boost the visible light photocatalytic activity of Bi4Ti3O12 (BTO) but limited by the concurrent formation of Bi2S3 nanorods by in-situ ion exchange reaction. MethodsAn amorphous carbon interlayer that can effectively protect the BTO fibrous structure and suppress the Bi2S3 generation was introduced to construct Bi4Ti3O12/C/Bi2S3/MoS2 (BCBM) composites with enhanced photocatalytic activity. The BCBM fibers were fabricated by electrospinning and subsequent hydrothermal growth of carbon and MoS2. Significant findingsOwing to the important roles of carbon interlayer to keep the integrity of the BTO fibrous structure and provide charge transfer channel, fast separation of photoinduced carriers happens on the semiconductor interface between BTO and MoS2 to improve the visible light photocatalytic activity. The optimum BCBM displays a photocatalytic efficiency of 88.4% and apparent constant of 0.0148 min−1 towards degrading RhB, which are much higher relative to the Bi4Ti3O12/Bi2S3/MoS2 composites prepared without the carbon interlayer. Moreover, it is demonstrated that the thickness of carbon interlayer is crucial for fabricating high-performance BTO heterojunctions with MoS2. The design and results in this work may broaden the horizon to construct the Bi-based semiconductor photocatalyst with high photocatalytic performance.

CuMoO4 nanorods-based acetone chemiresistor-enabled non-invasive breathomic-diagnosis of human diabetes and environmental monitoring

A nano-enabled low-trace monitoring system for acetone has the potential to revolutionize breath omics-based non-invasive diagnosis of human diabetes and environmental monitoring technologies. This unprecedented study presents the state-of-the-art facile and economic template-assisted hydrothermal route to fabricate novel CuMoO4 nanorods for room temperature breath and airborne acetone detection. Physicochemical attribute analysis reveals the formation of crystalline CuMoO4 nanorods with diameters ranging from 90 to 150 nm, and an optical band gap of approximately 3.87 eV. CuMoO4 nanorods-based chemiresistor demonstrates excellent acetone monitoring performance, with a sensitivity of approximately 33.85 at a concentration of 125 ppm. Acetone detection is rapid, with a response time of 23 s and fast recovery within 31 s. Furthermore, the chemiresistor exhibits long-term stability and selectivity towards acetone, compared to other interfering volatile organic compounds (VOCs) commonly found in human breath such as ethanol, propanol, formaldehyde, humidity, and ammonia. The linear detection range of acetone from 25 to 125 ppm achieved by the fabricated sensor is well-suited for human breath-based diagnosis of diabetes. This work represents a significant advancement in the field, as it offers a promising alternative to time-consuming and costly invasive biomedical diagnostics, with the potential for application in cleanroom facilities for indoor contamination monitoring. The utilization of CuMoO4 nanorods as sensing nanoplatform opens new possibilities for the development of nano-enabled, low-trace acetone monitoring technologies for non-invasive diabetes diagnosis and environmental sensing applications.

Hexahedron Symmetry and Multidirectional Facet Coupling of Orthorhombic CsPbBr3 Nanocrystals

The cube shape of orthorhombic phase CsPbBr3 nanocrystals possesses the ability of selective facet packing that leads to 1D, 2D, and 3D nanostructures. In solution, their transformation with linear one-dimensional packing to nanorods/nanowires is extensively studied. Here, multifacet coupling in two directions of the truncated cube nanocrystals to rod couples and then to single-crystalline rectangular rods is reported. With extensive high-resolution transmission electron microscopy image analysis, length and width directions of these nanorods are derived. For the seed cube structures, finding {110} and {002} facets has remained difficult as these possess the hexahedron symmetry and their size remains smaller; however, for nanorods, these planes and the ⟨110⟩ and ⟨001⟩ directions are clearly identified. From nanocrystal to nanorod formation, the alignment directions are observed as random (as shown in the abstract graphic), and this could vary from one to the other rods obtained in the same batch of samples. Moreover, seed nanocrystal connections are derived here as not random and are rather induced by addition of the calculated amount of additional Pb(II). The same has also been extended to nanocubes obtained from different literature methods. It is predicted that a Pb-bromide buffer octahedra layer was created to connect two cubes, and this can connect along one, two, or even more facets of cubes simultaneously to connect other cubes and form different nanostructures. Hence, these results here provide some basic fundamentals of seed cube connections, the driving force to connect those, trapping the intermediate to visualize their alignments for attachments, and identifying and establishing the orthorhombic ⟨110⟩ and ⟨001⟩ directions of the length and width of CsPbBr3 nanostructures.

Enhancement of Fracture Toughness in carbonate doped Hydroxyapatite based nanocomposites: Rietveld analysis and Mechanical behaviour

Highly nanocrystalline carbonated hydroxyapatite (CHAp) is synthesized by hydrothermal technique with four different stoichiometric compositions for microstructural and mechanical analysis. HAp is one of the most biocompatible material and addition of carbonate ions lead to increase in fracture toughness highly required in biomedical applications. The structural properties and its purity as single phase is confirmed by X-ray diffraction. Lattice imperfections and structural defects is investigated using XRD pattern model simulation, i.e. Rietveld's analysis. The substitution of CO32− in HAp structure leads to a decrease in crystallinity which ultimately lessens crystallite size of sample as verified by XRD analysis. FE-SEM micrographs confirms the formation of nanorods with cuboidal morphology and porous structure of HAp and CHAp samples. The particle size distribution histogram validates the constant decrease in size due to carbonate addition. The mechanical testing of prepared samples revealed the increase in mechanical strength from 6.12 MPa to 11.52 MPa due to the addition of carbonate content, which leads to a rise in fracture toughness, a significant property of an implant material from 2.93 kN to 4.22 kN. The cumulative effect of CO32− substitution on HAp structure and mechanical properties has been generalized for the application as biomedical implant material or biomedical smart materials.

Controllable Synthesis of N2-Intercalated WO3 Nanorod Photoanode Harvesting a Wide Range of Visible Light for Photoelectrochemical Water Oxidation.

A highly efficient visible-light-driven photoanode, N2-intercalated tungsten trioxide (WO3) nanorod, has been controllably synthesized by using the dual role of hydrazine (N2H4), which functioned simultaneously as a structure directing agent and as a nitrogen source for N2 intercalation. The SEM results indicated that the controllable formation of WO3 nanorod by changing the amount of N2H4. The β values of lattice parameters of the monoclinic phase and the lattice volume changed significantly with the nW: nN2H4 ratio. This is consistent with the addition of N2H4 dependence of the N content, clarifying the intercalation of N2 in the WO3 lattice. The UV-visible diffuse reflectance spectra (DRS) of N2-intercalated exhibited a significant redshift in the absorption edge with new shoulders appearing at 470-600 nm, which became more intense as the nW:nN2H4 ratio increased from 1:1.2 and then decreased up to 1:5 through the maximum at 1:2.5. This addition of N2H4 dependence is consistent with the case of the N contents. This suggests that N2 intercalating into the WO3 lattice is responsible for the considerable red shift in the absorption edge, with a new shoulder appearing at 470-600 nm owing to formation of an intra-bandgap above the VB edges and a dopant energy level below the CB of WO3. The N2 intercalated WO3 photoanode generated a photoanodic current under visible light irradiation below 530 nm due to the photoelectrochemical (PEC) water oxidation, compared with pure WO3 doing so below 470 nm. The high incident photon-to-current conversion efficiency (IPCE) of the WO3-2.5 photoanode is due to efficient electron transport through the WO3 nanorod film.