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Bioinspired nanochannels have emerged as a powerful tool for bioengineering and biomedical research due to their robust mechanical and controllable chemical properties. Inspired by inward-rectifier potassium (K

Ascorbic acid (AA) is one of the vital water-soluble antioxidants in blood serum and can function as a key blood serum biomarker for oxidative stress. Therefore, we have developed a highly sensitive and selective AA electrochemical sensor based on novel porous silicon-mesoporous carbon nanocomposites (PSi-MC NCs) modified glassy carbon electrode (GCE). The structural properties and morphological investigation of the PSi-MC NCs were systematically studied by different techniques. This newly designed PSi-MC/GCE-based non-enzymatic electrochemical sensor can measure an extremely wide range of AA (0.5–2473 μM) in phosphate buffer solution (PBS) with a sensitivity 0.1982 μAμM−1cm−2 and a logical limit of detection (LOD) 30.0±0.1 nM. The proposed AA sensor was also applied to detect possible interference from common interfering substances that are present in human blood, showing highly selective performance. The proposed AA sensor also showed highly acceptable results towards the detection of AA levels in human blood serum and vitamin C tablets. This new combination of active material PSi-MC NCs provided steady, excellent reproducibility, repeatability, and long-term stability.

Creation of novel clean light responsive photocatalytic organization requires adequate technical skills and exhaustive efforts. The aim of the current study is to create novel, highly influential photocatalyst frameworks working under visible-light utilizing ZnO/SnO2 nanocomposites in conjugation with biomass originated active carbon (AC) for environmental concerns. The ZnO/SnO2 nanocomposite was created by the sol-gel approach followed by ultra-sonication technique to form trio combination with AC. The XRD investigation displays rutile tetragonal structure of SnO2 and hexagonal wurtzite phase of ZnO in all fabricated nanocomposites. The XPS and FTIR investigations confirmed the elemental composition and successful establishment of trio structure of AC, ZnO and SnO2. Perfect tailoring during the creation process results in achieving band gap values of various AC@ZnO/SnO2 nanocomposites in visible region. The FESEM images of AC@ZnO/SnO2 nanocomposites exhibit particles, rods and sheets like-structures confirming the successful creation of impeccable organization among AC, ZnO and SnO2. The HR-TEM image of 10% AC@ZnO/SnO2 nanocomposite revealed the crystallographic planes (101) and (110) for hexagonal wurtzite ZnO and tetragonal rutile of SnO2. Among various created nanostructures, the 10% AC@ZnO/SnO2 trio organization was found to be the most influential with 94.6 % removal of target linezolid antibiotic and almost complete destruction of insecticide imidacloprid and MB complex structure in just 25 minutes under visible light condition. The 10% AC@ZnO/SnO2 photocatalyst was found to be the most influential candidate giving ⁓ 8.16 times higher detrimental skills than that of pure SnO2. These extraordinary outputs by the newly fabricated 10%AC@ZnO/SnO2 photocatalyst open a new gateway to exploit this promising material towards various environmental issues.

Membrane technology has been embraced as a feasible and promising substitute to the traditional technologies employed for biodiesel synthesis which are energy and time consuming. It needs less energy, has high stability, is environmentally friendly, and is simple to operate and control. Therefore, in our current study membrane technology was employed to synthesize biodiesel from Toona ciliate novel and non-edible seed oil. Since Toona ciliata has affluent oil content (33.8%) and is effortlessly and extensively available. In fact, we intended to scrutinize the effects of green synthesized barium oxide nanoparticles for one step transesterification of biodiesel production using membrane technology followed by characterization of prepared catalyst via innovative techniques. Optimal yield of biodiesel attained was 94% at 90 °C for 150 min with methanol to oil molar ratio of 9:1 and amount of about 0.39 wt %. Quantitative analysis of synthesized Toona ciliata oil biodiesel was carried out by advance techniques of Gas chromatography mass spectrometry (GC-MS), Fourier-transform infrared (FTIR) spectroscopy and Nuclear magnetic resonance (NMR) which authorize the synthesis of fatty acid methyl ester compounds using oil from Toona ciliata seeds. Values of Toona ciliata fuel properties for instance flash point (70°C), density (0.89 kg/m

The mixed ionic-electronic conducting (MIEC) oxides have generated significant research efforts in the scientific community during the last 40 years. Since then, many MIEC compounds, most of which are based on perovskite oxides, have been synthesized and characterized. These compounds, when heated to high temperatures, form solid ceramic membranes with high oxygen ionic and electrical conductivity. The driving force for oxygen ion transport is the ionic transfer of oxygen from the air as a result of the differential partial pressure of oxygen across the membrane. Electronic and ionic transport in a range of MIEC materials has been studied using the defect theory, particularly when dopants are introduced to the compound of interest. As a result, many types of ionic oxygen transport limits exist, each with a distinct phase shift depending on the temperature and partial pressure of oxygen in use. In combination with theoretical principles, this work attempts to evaluate the research community's major and meaningful achievements in this subject throughout the preceding four decades.

This study reports a microemulsion method to successfully prepare nanocrystalline (cobalt or nickel) iron tungstate powders (Nix or Cox)Fe1−XWO4 (where X = 0 and 0.5). The powders were calcined at a temperature of 600 °C for 6 hours and optimized at pH 10. The change in the crystal structure, microstructure, crystallite size, optical properties, and specific surface area were investigated using XRD, FTIR, TEM, and surface area analysis (SBET). The optical, electrical, and magnetic properties were explained using UV-vis, PL, the Hall-effect, and VSM. The findings indicate that the tungstate powders had average particle sizes of around 12–18 nm. The mean pore diameter was 4.5–6.3 nm, and the specific SBET of the material obtained was approximately 13.72–17.69 m2 g−1. The photocatalytic activity of methylene blue (MB) dye decolorization has been investigated. In MB dye photodegradation, the as-prepared NiFeWO4 powders demonstrated substantial improvement (100% after 60 min). The obtained results reveal NiFeWO4 powders with uncomplicated production, high UV-light photocatalytic activity, and recyclable properties.

The coupling between inorganic semiconductor metal oxide and nanocarbon material is a proper route to fabricate efficient electrochemical sensors. Herein, the electrocatalytic oxidation, detection of nitrite ions (NO2−) is investigated using reduced graphene oxide/mesoporous zinc oxide (rGO/ZnO) nanocomposite-modified glassy carbon electrode (GCE). The mesoporous ZnO and rGO were prepared via a modified sol-gel in presence of F127 structural template agent and modified Hummers’ methods, respectively. The rGO/ZnO nanocomposite was then produced via a simple ultrasonication and characterized using various analytical techniques to examine the morphology, structure and chemical constituents. The newly-developed rGO/ZnO/Nafion nanocomposite exhibited remarkable sensing response towards NO2− oxidation compared to bare GCE or ZnO/Nafion/GCE. The rGO/ZnO/Nafion/GCE sensor demonstrated a linear dynamic range between 200 and 4000 µM for linear sweep voltammetry (LSV) and 20 to 520 µM (for amperometry). Remarkable sensitivity and low limit of detection (LOD: at S/N = 3) were projected to be 0.3156 μAμM−1cm−2 and 1.18 μM for LSV, whereas values of 0.2754 μAμM−1cm−2 and 1.36 µM were obtained using the amperometric technique. The modified electrocatalyst demonstrated excellent operational stability, reproducibility and anti-interfering ability towards several common active species. The developed rGO/ZnO/GCE electrode represents a favorable strategy for efficient detection and quantification of NO2− by the electrochemical approach.

Nowadays, synthetic polymers are used in medical applications due to their special biodegradable, biocompatible, hydrophilic, and non-toxic properties. The materials, which can be used for wound dressing fabrication with controlled drug release profile, are the need of the time. The main aim of this study was to develop and characterize polyvinyl alcohol/polycaprolactone (PVA/PCL) fibres containing a model drug. A dope solution comprising PVA/PCL with the drug was extruded into a coagulation bath and became solidified. The developed PVA/PCL fibres were then rinsed and dried. These fibres were tested for Fourier transform infrared spectroscopy, linear density, topographic analysis, tensile properties, liquid absorption, swelling behaviour, degradation, antimicrobial activity, and drug release profile for improved and better healing of the wound. From the results, it was concluded that PVA/PCL fibres containing a model drug can be produced by using the wet spinning technique and have respectable tensile properties; adequate liquid absorption, swelling %, and degradation %; and good antimicrobial activity with the controlled drug release profile of the model drug for wound dressing applications.

Nitrogenated graphene oxide-decorated copper sulfide nanocomposites (Cu

The biogas production (BP), volatile fatty acids (VFAs), microbial communities, and microbes' active enzymes were studied upon the addition of biochar (0-1.5%) at 6% and 8% slaughterhouse waste (SHW) loadings. The 0.5% biochar enhanced BP by 1.5- and 1.6-folds in 6% and 8% SHW-loaded reactors, respectively. Increasing the biochar up to 1.5% caused a reduction in BP at 6% SHW. However, the BP from 8% of SHW was enhanced by 1.4-folds at 1.5% biochar. The VFAs production in all 0.5% biochar amended reactors was highly significant compared to control (p-value 0.05). The biochar addition increased the bacterial and archaeal diversity at both 6% and 8% SHW loadings. The highest number of OTUs at 0.5% biochar were 567 and 525 in 6% and 8% SHW, respectively. Biochar prompted the Clostridium abundance and increased the lyases and transaminases involved in the degradation of lipids and protein, respectively. Biochar addition improved the Methanosaeta and Methanosphaera abundance in which the major enzymes were reductase and hydrogenase. The archaeal enzymes showed mixed acetoclastic and hydrogenotrophic methanogenesis.

Nanostructured polymeric membranes are of great importance in enhancing the antifouling properties during water filtration. Nanomaterials with tunable size, morphology and composition, surface modification, and increased functionality provide considerable opportunities for effective wastewater treatment. Thus, in this work, an attempt has been made to use spinel-structured MnCo

Chemical sensors fabricated from porous silicon (PSi) for liquid organic analytes (ethanol, acetonitrile, methanol and acetone) are demonstrated, with an emphasis on the impact of the Ag electrical contact placement on sensor performance. Sensors with front side contact display larger shift in capacitance response (2–3 times more sensitive) compared to the backside sensor design as the solvents immediately interact with the pore openings before infiltration. Much slower response time (7–30 min range) for front side vs. (50–200 s scale range) for backside configuration is observed. Both sensor designs exhibit excellent solvent infiltration-evaporation reversible response, indicating no chemical reaction or surface modification occurred. The response time was in the order of ethanol > acetonitrile > methanol > acetone, which correlates well with the solvent vapor pressure. The capacitance shift in both sensor devices is likely related to the interface interaction, revealing a closer correlation with the dipole moments of solvents. This is supported by the photoluminescence quenching upon exposure to organic solvents, with a relative intensity decrease tracks with the dipole moment. The sensitivity remains sufficiently high during the repeated use, with excellent storage stability for backside contact. This comparative study suggests the viability of the current sensor structure and design particularly with backside contact for sensing of various chemical analytes with notably sensitivity and extremely rapid response. Keywords: Meso-porous silicon, Electrical sensor, Capacitance, Photoluminescence, Organic solvents

Background Heteroatom-doped carbon structures derived from sustainable biomass for energy storage applications are a promising aspirant to the scientific community. Highly efficiency activated carbon materials derived from cheap, plentiful, but unwanted natural wastes are interestingly promising for large-scale applications. Methods Facile methods of chemical activation and carbonization using a simple pyrolysis technique under inert atmosphere were applied to synthesize heteroatom-doped porous activated carbon nanoflakes using Sechium edule leaves as biomass precursor. Significant findings The research findings of the present work indicate large effective surface area and porosity of as-synthesized nitrogen-doped activated carbon nanoflakes that led to display excellent specific capacitance of 334 F g−1 at 1 A g−1 current density in strong acidic electrolyte using a three-electrode system. The electrokinetic analysis demonstrate that the major contribution of capacitive nature (90%) was observed to accumulate the total charge. Further, all solid-state symmetric supercapacitor (SSC) devices fabricated using as-synthesized carbon nanoflakes with gel electrolyte (PVA-H2SO4) exhibited a maximum capacitance of 114 F g−1 at 1 A g−1, a maximum energy density of 63.33 Wh kg−1 and power density of 10 kW kg−1. The retention of specific capacitance was found to be 93% with 5000 continuous cycles of charge-discharge process.

Modification and bandgap engineering are proposed to be extremely significant in improving the photocatalytic activity of novel photocatalysts. The current research focused on the fabrication of ultrafast and efficient visible light-responsive ternary photocatalyst containing g-C3N4 nanostructures in conjugation with polypyrrole doped carbon black (PPy-C) and gold (Au) nanoparticles by highly effectual, simple, and straightforward methodology. Various analytical techniques like XRD, FESEM, TEM, XPS, FTIR, and UV–Vis spectroscopy were applied for characterization purposes. The XRD and XPS results confirmed the successful creation of a nanocomposite framework among Au, PPy-C and g-C3N4. The TEM images revealed that bare g-C3N4 holds sheets or layered graphitic structure with sizes ranging from 100 to 300 nm. The sponge-like PPy-C network intermingled perfectly with g-C3N4 sheets along with homogeneously distributed 5–15 nm Au nanoparticles. The band gap energy (Eg) for bare g-C3N4, PPy-C/g-C3N4 and Au@PPy-C/g-C3N4 nanocomposites were found to be 2.74, 2.68, and 2.60 eV, respectively. The photocatalytic activity for all newly designed photocatalysts have been assessed during the degradation of insecticide Imidacloprid and methylene blue (MB) dye, where Au@PPy-C/C3N4 was found to be extremely efficient with ultrafast removal of both imidacloprid and MB in just 25 min of visible light irradiation. It was revealed that the Au@PPy-C/g-C3N4 ternary photocatalyst removed 96.0% of target analyte imidacloprid, which is ⁓ 2.91 times more efficient than bare g-C3N4 in treating imidacloprid. This report provides a distinctly promising, highly effectual and straightforward route to destruct extremely toxic and notorious pollutants and opens a new gateway in the present challenging scenario of environmental concerns.

CsPbX3 perovskite nanocrystals (NCs), with excellent optical properties, have drawn considerable attention in recent years. However, they also suffer from inherent vulnerability and hydrolysis, causing the new understanding or new applications to be difficultly explored. Herein, for the first time, it is discovered that the phospholipid membrane (PM)-coated CsPbX3 NCs have intrinsic biocatalytic activity. Different from other peroxidase-like nanozymes relying on extra chromogenic reagents, the PM-CsPbX3 NCs can be used as a self-reporting nanoprobe, allowing an "add-to-answer" detection model. Notably, the fluorescence of PM-CsPbX3 NCs can be rapidly quenched by adding H2 O2 and then be restored by removing excess H2 O2 . Initiated from this unexpected observation, the PM-CsPbX3 NCs can be explored to prepare multi-color bioinks and metabolite-responsive paper analytical devices, demonstrating the great potential of CsPbX3 NCs in bioanalysis. This is the first report on the discovery of nanozyme-like property of all-inorganic CsPbX3 perovskite NCs, which adds another piece to the nanozyme puzzle and opens new avenues for in vitro disease diagnostics.

Herein, one-step synthesis of Cr2O3/Bi2S3 nanorods at various Cr2O3 contents (0.01–0.05%) is developed using a hydrothermal approach for degradation of two organic pollutants such as phenol and methylene blue (MB) under visible light irradiation. TEM observation showed that the Cr2O3 NPs around 5 nm at very small content decorated the surface of Bi2S3 nanorods. The photocatalytic performance of synthesized photocatalyst exhibited an effective photocatalytic efficiency of about 90% for Phenol and 80% for MB upon visible light exposure. The photocatalytic performance of 0.04% Cr2O3/Bi2S3 heterostructure was enhanced 2.66 and 2.25 times larger than bare Bi2S3 nanorods for degradation of MB and phenol, respectively. The temperature-programmed desorption ensures that Cr2O3/Bi2S3 heterostructure has more acidic active sites, which increased the OH radical absorption and then increased the photocatalytic efficiency. The electrochemical impedance spectroscopy (EIS), photoelectrochemical behavior and photoluminescence spectra were measured as evidence for the photocatalytic mechanism. The results indicated that the construction Cr2O3/Bi2S3 heterostructure has significantly suppressed the recombination rate of photoinduced carriers and consequently enhanced its photocatalytic efficiency. Additionally, the Cr2O3/Bi2S3 heterostructure revealed high recyclability, durability and stability for five cyclic runs without significant loss of the photocatalytic performance, making the synthesized photocatalyst promising for the remediation of wastewater under sunlight.

In this work, we demonstrate the use of annealed sol-gel derived ZnO nanoparticles acting as electron transport layer (ETL) in inverted bulk heterojunction (BHJ) polymer solar cells (PSCs). We have examined the photovoltaic performance of devices based on poly(2-methoxy-5-(2-ethylhexyloxy)- p -phenylenevinylene) (MEH-PPV):(6,6)-phenyl-C61-butyric acid methyl ester (PC 61 BM) blend system employing the ZnO nanoparticles as an ETL with CuI as hole transport layer (HTL) in comparison to the case of using the conventional HTL of poly(3,4-ethylenedioxythiophene)/poly(styrene sulfonate) sulfonic acid (PEDOT:PSS). The effect of the presence of another layer of ZnO macrospheres attached to the ZnO nanoparticles is also investigated. The highest power conversion efficiency (PCE) value of 1.35% was achieved for device: ITO/ZnO nanoparticles/MEH-PPV:PC 61 BM/CuI/Ag, which is 275% more the value obtained when CuI was replaced by PEDOT:PSS. The comprehensive analyses on structural and optical characteristics including SEM, XRD, FTIR, PL and UV–vis spectroscopy indicated that the use of the ZnO nanoparticles alone as ETL, together with the CuI as HTL could effectively reduce trap-assisted recombination and charge accumulation at the interface, which is beneficial for the enhanced device performance.

In this work, a hydrazone chemistry assisted DNAzyme has been designed and constructed. The introduction of hydrazone chemistry increases the versatility of DNAzymes. With superior catalytic capability, the hydrazone chemistry assisted DNAzyme has been successfully applied for the analysis of double targets. Taking 5-hydroxymethylfurfural (HMF) and lipopolysaccharide (LPS) as samples, the hydrazone chemistry assisted DNAzyme can be used for the detection of different combinations of targets. Moreover, because hydrazone chemistry is popular in nature, this work may also provide a new insight for the development of DNAzymes and their multifunctionality.

The development and designing of self-testing blood-glucose electrochemical biosensor is an effective approach for diabetic patients to overcome and control this high health concerning issue. Herein, we successfully designed novel single-walled carbon nanotubes-porous silicon nanocomposites framework (SWCNTs-PSi NCs) via simple stain etching and ultrasonication techniques. X-ray Diffraction (XRD), Raman spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM), Transmission Electron Microscopy (TEM), Energy-Dispersive Spectroscopy (EDS), and X-ray Photoelectron Spectroscopy (XPS) were employed to study the porous morphology with ~30 nm pore size and overall structural characterization of the SWCNTs-PSi NCs. This newly fabricated SWCNTs-PSi modified glassy carbon electrode (GCE) biosensor can measure an extremely wide range of glucose (0.5–28.5 mM) in phosphate buffer solution (PBS) compared to the regular glucose concentration level in human blood serum (3.9–7.1 mM) with a sensitivity 0.0614 μAmM−1 cm−2 and detection limit 9.6 ± 0.1 μM. This non-enzymatic glucose biosensor demonstrated excellent selectivity during the investigation of the possible impact of common interfering substances that are present in human blood. This proposed non-enzymatic glucose biosensor has also been tested for real human blood serum analysis to determine blood glucose levels showing highly motivated results. The newly designed SWCNTs-PSi/GCE biosensor exhibits excellent reproducibility and repeatability, along with long-term stability.

Designing and fabrication of novel visible light active photocatalysts is still a challenging task, which requires highly dedicative efforts and professional skills. The current work focused to design distinct visible-light responsive photocatalysts based on Bi2S3 in combination with Pt nanoparticles for environmental remediation. The Pt/Bi2S3 frameworks were developed by a simple one-pot hydrothermal methodology followed by a photo-deposition technique. The XRD analysis confirmed the orthorhombic Bi2S3 with high degree of crystallinity whereas the FTIR and XPS investigations further confirmed the successful creation of hybrid nanostructures between Pt and Bi2S3 nanomaterials. FESEM analysis showed the flakes like appearance of Bi2S3 arranged in stacking or piling pattern. TEM analysis revealed that the Pt nanoparticles (varied from 8 to 15 nm) were evenly distributed onto Bi2S3 nanoflakes ranging from 50−150 nm in size. The UV–vis spectroscopic analysis showed the lowering of energy bandgap upon addition of Pt into Bi2S3 nanoflakes. The newly designed Pt/Bi2S3 photocatalysts were tested for their photocatalytic skills on gemifloxacin mesylate drug under visible light illumination. The 1% Pt/Bi2S3 displayed an exceptional performance with 93.0 % drug removal after 25 min and complete destruction of methylene blue (MB) dye in just 30 min under visible-light source. The newly fabricated 1% Pt/Bi2S3 photocatalyst was found to be an extraordinary candidate among all samples, giving 1.9 times higher degradation skills than that of bare Bi2S3. These promising features of the 1% Pt/Bi2S3 framework might be beneficial for its utilization in various environment related challenging tasks.

Rapid and efficient identification of pathogen is indispensable in clinical diagnosis because of the extremely severe consequence induced by pathogens infection. Taking advantages of the various compositions of pathogen surfaces, in this work we have proposed a simple and rapid sensor array for different pathogens identification and discrimination based on two-dimensional metal–organic frameworks (2D-MOFs) conjugated with functional peptide. Owing to the outstanding physical and chemical properties, ultrathin 2D-MOFs can adsorb dye-labeled peptides and consequently quench the fluorescence quickly and efficiently. Nevertheless, in the presence of pathogens, the anionic surface and different bimolecular composition of pathogens will endow them to interact with the 2D-MOFs or peptides through the diverse non-specific interactions. Subsequently, the dye-labeled peptides can be released with a recovery of fluorescence intensity. Consequently, the sensor array can identify various pathogens rapidly and efficiently based on the distinct fluorescence response patterns. Moreover, experimental results reveal that this approach can discriminate different pathogens with 100% accuracy, even in urine or mixed samples, demonstrating its reliability and effectiveness in the complex biological samples. More importantly, the procedure of pathogens identification by using this sensor array is very fast with only ~ 15 min, indicating the great potential applications in the timely clinical treatments and reliable monitoring of infectious disease trends.

We propose herein initial results to develop optimum redox mediators by the combination of computational simulation and catalytic functionalization of the core structure of vitamin K3. We aim to correlate the calculated energy value of the LUMO of different vitamin K3 derivatives with their actual redox potential. For this, we optimized the catalytic alkylation of 1,4-naphthoquinones with a designed Ag(i)/GO catalyst and synthesized a series of molecules.

The combination of inorganic semiconductor metal oxides and organic conducting polymers is a favorable strategy in fabricating electrochemical sensors due to their outstanding electrocatalytic performance. Herein, a novel electrochemical sensor for detection of liquid methanol is fabricated using a modified glassy carbon electrode (GCE) with Nafion binder. The active sensing material is composed of a conductive polythiophene (PTh) doped iron oxide (α-Fe2O3) that simply synthesized by a facile sol-gel route in presence of a structure directing agent F127 followed by an oxidative polymerization process. Cyclic voltammetry and electrochemical impedance measurements revealed enhanced electrocatalytic response at the PTh/α-Fe2O3/Nafion modified GCE compared to either α-Fe2O3/GCE or bare GCE with a diffusion-controlled kinetics in ferro/ferricyanide redox couple. Material characterization using various analytical techniques confirmed the formation of PTh sheets onto highly crystalline rhombohedral structure of α-Fe2O3 with distinctly lattice fringes 0.37 nm. Outstanding sensing parameters are achieved with a sensor sensitivity of 0.793 μAmM−1cm−2, limit of detection LOD at (S/N = 3) = 1.59 mM, a wide range of methanol concentration from 5 to 1000 mM with a correlation coefficient R2 = 0.9483. Furthermore, the current proposed sensor electrode showed adequate operational stability and acceptable reproducibility and repeatability.

Mesoporous Ag/ZnO nanocrystals have been successfully synthesized at different Ag contents (0–10 wt%) through a single-step sol–gel method in presence of triblock copolymer as a structure directing agent. The as-prepared hybrid materials were calcined at 450 °C in air for 4 h, subsequently, Ag nanoparticles have been photo-reduced from AgNO3 onto mesopores ZnO nanocyrstals. The XRD and Raman analysis revealed that well crystalline ZnO hexagonal wurtzite phase and face-centered cubic metallic Ag nanoparticles were formed. TEM images of mesoporous ZnO nanocrystals showed that synthesized materials composed of discrete ZnO nanoparticles agglomerated with worm-like mesoporous structure. The lattice fringes exhibit the typical distances, i.e., Ag(1 1 1) and ZnO(1 0 0) and the average Ag and ZnO nanoparticle diameters are ∼5 and 10 nm, respectively. The photocatalytic performance of different prepared photocatalysts was evaluated by degradation of methylene blue (MB) under visible light irradiation. The results indicate that the photocatalytic efficiencies of mesoporous ZnO photocatalysts were remarkably enhanced by adding 1% Ag nanoparticles which completely degrade the target MB dye within 150 min. The photodegradation rate was found to increase linearly with increasing the Ag contents from 0 to 1% and it is faster 2.2 times than undoped ZnO. From economic point of view, 1% Ag/ZnO photocatalyst contains optimum Ag content as there is no significant increase in the photocalatytic performance at higher Ag content.

Photoluminescence and UV–Vis spectral evaluation of a poly allyl diglycol carbonate (CR-39) detector coated by poly(2-methoxy-5-(2-ethyl-hexyloxy)-1,4-phenylene-vinylene) (MEH-PPV) conducting polymer are demonstrated. The CR-39 surfaces were exposed to thin 241Am disk source that emits alpha particles with activity 333 kBq. Surface modification of the detector by MEH-PPV was acquired by a simple dip coating process. Our findings revealed that the spectroscopic analysis using FTIR is insensitive approach to detect the induced modifications in the irradiated samples. Additionally, the track density of the irradiated samples affects significantly the photoluminescence and UV–Vis responses of the CR-39 samples. The spectral peak heights and the integrated intensities under the peaks exhibit linear correlations (correlation coefficient R2 = 0.9904 to 0.9968) with the fluence of alpha particles. The linear fitting functions together with the corresponding fitting parameters were evaluated. Both techniques exhibited remarkable spectral differences for the irradiated samples, and hence they could be employed to provide sensitive methods for alpha particle detection. Results of sample fabrication and modification, along with structural and optical evaluation are addressed and thoroughly discussed.

Silver nanoparticles (AgNPs) have been reduced onto porous silicon (PSi) surface in a simple immersion plating bath. Here, PSi with average pore size of ∼30 nm was used as both a mechanical support and a mild reducing agent. AgNPs-meso-PSi hybrid structures exhibit a highly sensitive and reproducible surface-enhanced Raman scattering (SERS) response. A detectable concentration as low as 100 pM of crystal violet has been achieved with an enhancement factor (EF) of 1.3 × 10 6 . No aging effect was observed for the current substrates after storing in air for three weeks. The large EF is essentially attributed to a combination of electromagnetic enhancement and charge transfer mechanism.

We developed a simple and mild one-step chemical method to produce novel and highly efficient α-Fe2O3/polypyrrole (PPy) photocatalysts. The formation of α-Fe2O3/PPy nanocomposites proceeds via a simultaneous gelation and polymerization process. The XRD results revealed that all the diffraction peaks can be perfectly indexed to the rhombohedral structure of α-Fe2O3 and the polymerization of Py did not change the crystalline phase of α-Fe2O3. TEM images show that Fe2O3 nanoparticles are quite uniform in shape and size and their particle sizes are decreased from 20 to 5 nm by increasing Py content from 5 to 25%. The lattice fringes (3.7 A) are distinctly visible and revealed structurally uniform crystals of α-Fe2O3 without dislocation. Compared to pure Fe2O3, the newly developed nanocatalyst demonstrated a remarkable activity toward the photocatalytic degradation of methylene blue (MB) under UV irradiation, at ambient temperature. Complete degradation of MB was achieved after only 20 min in the presence of the optimum photocatalyst containing 10% Py. The effective photocatalytic performance is associated with the mesoporous structure and crystalline nature of the prepared nanocomposites. Additionally, such enhanced photocatalytic behavior was rationalized in terms of a synergetic effect for light absorption between α-Fe2O3 and PPy that eventually led to better charge separation and suppression of charge recombination. The photocatalyst could be removed from the reaction mixture and its recyclability remains effective after five cyclic runs. Proposed mechanism for the degradation of MB with the α-Fe2O3/PPy nanocatalyst under UV irradiation is also presented and thoroughly discussed.

The aim of the present work is to enhance the photonic efficiency of mesoporous ZnO films by photodeposition of Ag nanoparticles. Mesoporous ZnO multilayer films were synthesized by a sol–gel method in the presence of triblock co-polymer Pluronic (F-127) as a template agent, followed by spin coating on soda lime glass substrates. The as-prepared mesoporous ZnO films with different layers (1–10) were calcined at 450 °C for 3 h. Ag nanoparticles were photodeposited onto mesoporous ZnO multilayer films. XRD results of Ag/ZnO films indicated that ZnO nanoparticles had a hexagonal wurtzite structure with a highly crystalline state. TEM images revealed that Ag nanoparticles are agglomerated and all pores can be regarded as irregular voids between ZnO particles and the prepared films have a large amount of voids. The prepared films have been evaluated by the determination of their photonic efficiencies during degradation of methylene blue (MB). The photonic efficiencies of mesoporous ZnO and Ag/ZnO films were found to improve with increasing number of layers from 1 to 5 and a further increase in film thickness (10 layers) doesn't lead to any enhancement in photoactivity. MB photodegradation was enhanced significantly when Ag was photodeposited onto ZnO using 5 layers with 1.165% photonic efficiency. The prepared Ag/ZnO with different layers demonstrates a highly stable nature of the designed photocatalyst with almost the same photocatalytic performance after 10 repeated cycles.

A capacitive sensor based on porous silicon (PSi) for detection of various polar (ethanol, methanol, acetone, acetonitrile, chloroform) and non-polar organic solvents (n-hexane, toluene) was described. The meso-PSi layer with an average pore size of 30 nm was prepared by a galvanostatic electrochemical etching of crystalline silicon in HF-based solution. Surface passivation was conducted by anodic oxidation process and the electrical contacts were made exclusively onto the front porous structure. The as-fabricated sensor exhibits highly sensitive and reversible response toward polar organic molecules during the real-time measurements of capacitance, whereas the capacitive sensing behavior was irreversible and opposite in direction in case of non-polar solvents. The response time was in the order of acetone

The optical chemosensor technology demands to design a single, preconcentrator based sensing system having higher sensitivity, sufficient selectivity and efficient removal of metal ions with simple operating and recognition methodology. Here we successfully designed mesoporous TiO2 based sensing system which can be utilized as “naked eye” colorimetric sensor with simultaneous removal of the Bi(III) ions in a single step by strong interaction between TiO2 and [Bi(DZ)3] complex. This is explained by the small particle size (10 nm) and large surface area (174 m2/g) of mesoporous TiO2, which plays an important role in terms of accessibility and adsorption amount of [Bi–(DZ)3] complex. The designed sensing system shows high sensing ability even at trace level concentration of Bi(III) ion suggesting easier flow of Bi(III) ion over a wide range of concentrations. The detection limit for Bi(III) ions is estimated to be ∼1 ppb. One of the major advantages of current sensing system is the selective sensing performance up to 5000 times higher concentration of interfering cations and anions than that of Bi(III) ions. This novel approach provides a new route for simultaneous detection and removal Bi(III) ions in a single step and can be a time and cost alternative tool for environmental safety.

Highly crystalline ZnO–SiO2 films obtained by a sol–gel method at different ZnO contents were deposited on silicon substrate (P(100)) using spin coating process. The XRD results revealed that the strong ZnO(100) peak is grown with highly c-axis oriented film and the crystallinity is progressively improved with increasing ZnO contents. SEM micrographs of the films deposited on silicon substrate show a homogeneous and uniformity structure at different ZnO content. The prepared ZnO–SiO2 films are compared with either a film prepared from a commercial photocatalysts Hombikat UV-100 or Pilkington Glass Activ™ by the determination of their photonic efficiencies for degradation of methylene blue. The photocatalytic efficiency of the 10 wt% ZnO–SiO2 film was found to be about four times higher than film prepared from UV-100 or Pilkington Glass Activ™. The photocatalytic efficiencies of ZnO–SiO2 films are increased with increasing ZnO content from 1 wt% to 10 wt% ZnO and then decreased at 15 wt% ZnO. The order of photocatalytic efficiencies of ZnO–SiO2 films at different ZnO content and commercial photocatalysts after 6 h illumination were as following: 10 wt% ZnO > 15 wt% ZnO > 1 wt% ZnO > as-prepared 10 wt% ZnO–SiO2 film > UV-100 > Pilkington Glass Activ™, which suggested that the ZnO–SiO2 films are photoactive than commercial photocatalysts. The improved efficiency and potentially the low-cost synthesis suggest that this material might be practically useful as a photocatalyst film.

The synthesis and surface properties of a composite material consisting of porous silicon/magnetite nanoparticles (PSi/Fe3O4 NPs) are demonstrated. PSi layers with intermediate pore size (∼100 nm) are prepared by electrochemical porosification of n-type Si wafer in a hydrofluoric acid-containing oxidizing agent and surfactant. The intrinsically luminescent PSi templates are infiltrated with ferromagnetic Fe3O4 NPs grown by a simple hydrothermal approach with average sizes ranging from 8 to 30 nm. The photoluminescence intensity of magnetic nanocomposite was enhanced after Fe3O4 loading, probably due to the recombination of photoexcited carriers within the nanocrystallites. Magnetization measurement for the nanocomposites indicated that the magnetic nanoparticles retain their ferromagnetic characteristic at room temperature. The nanocomposites have been characterized by various techniques including, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) and magnetic measurements. The biocompatibility of both components and the ability to tailor the magnetic properties of the composite might be useful for magnetic and biomedical applications.

A nanostructured CoPt magnetic film was deposited from a single electrolyte into porous silicon layer by an electrochemical technique, followed by annealing at 600 °C in Ar atmosphere during which the CoPt alloy was converted to L10 ordered phase. Porous silicon with pore diameter between 5 and 100 nm was firstly fabricated by galvanostatic anodization of n-type silicon wafer in the presence of CrO3 as oxidizing agent and ethanol or sodium lauryl sulfate as surfactants. The role of the surfactant on the produced pore size and morphology was investigated by means of UV–vis spectra. As-formed porous silicon was consequently used as a template for the electrodeposition of magnetic CoPt film. The phase formation, microstructure and the magnetic properties were fully analyzed by XRD, FE-SEM, EDS and VSM measurements. It was found that, upon annealing the coercivity was significantly increased due to the transformation to the L10 ordered structure. The saturation magnetization and remanence ratio were also found to increase, indicating no loss of Co content or oxidation reaction after the annealing. Results of synthesis and characterization of CoPt/porous silicon nanocomposite are addressed and thoroughly discussed.

Ni–Cu–Si heterojunction was prepared by the liquid phase epitaxy (LPE) technique. Two growth solutions containing Indium (In) with Cu pieces and In with Ni pieces were employed during the fabrication process. The as-formed junction was directly characterized by different techniques including scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and thin film X-ray diffraction (XRD) measurements. The current–voltage ( I – V ) characteristics of the Au/Ni/Cu/Si diode were found to be nonlinear, asymmetric, having a good rectification behavior with a very small leakage current of 0.003 μA at a reverse bias voltage of 2.0 V. The value of turn on voltage was located at 0.2 V. The magnetic properties were also evaluated at room temperature with a vibrating sample magnetometer. Systematic study of junction fabrication and characterization of such a heterosystem, comparison of the behavior of flat silicon and nanoporous silicon as substrates are presented and thoroughly discussed.

Spinel nickel zinc ferrite nanowires were successfully prepared in mesoporous silica SBA-15 as a host matrix. The powder was annealed at a range of temperatures (500–900 °C) with heating rate 0.5 °C/min. The required NiZnFe2O4 phase was obtained at 700 °C. The specific surface area SBET data revealed that the surface area of the mesoporous silica after annealing was decreased from 821 to 90 m2/g which indicated that the spinal ferrite fills the channels of mesoporous materials. The one-dimensional spinel nanostructures were characterized by X-ray diffraction, infrared spectroscopy, vibrating sample magnetometer, and transmission electron microscopy before and after a selective removal of the silica template in aqueous solution of NaOH or HF. The presence of SBA-15 lowers the formation temperature of nickel zinc ferrite nanowires compared to the corresponding bulk material. The magnetic properties revealed a high saturation magnetization level (~43 emu/g) for the Ni–Zn nanowires at 900 °C.