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It is critical to design bifunctional nonprecious electrocatalysts with low costs and high efficiency for hydrogen production. Conventional electrocatalysts, on the other hand, frequently exhibit s...

Herein, we report a successful synthesis of supramolecularly assembled polyaniline/silver oxide/graphene oxide composite (PANI/Ag2O/GO) for enhanced NO2 gas sensing application. The PANI/Ag2O/GO composite was synthesized by facile stirring followed by an ultrasonication process. The prepared material was characterized by different techniques such as x-ray diffraction, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy and Raman-scattering spectroscopy. The detailed analysis revealed that the average crystallite sizes of PANI/Ag2O and PANI/Ag2O/GO composites were found to be 37.37 nm and 41.55 nm, respectively. FESEM and TEM analysis showed coral-like rough-surfaced and extensively agglomerated morphology for PANI and ultrathin flexible sheet-like morphology for GO. Ag2O nanoparticles with diameters 20–30 nm were well incorporated in the GO sheets and PANI matrix in the case of PANI/Ag2O/GO composites. The synthesized materials were used to make resistive sensor devices that had a high response to NO2 gas. The fabricated sensors were examined at various temperatures to obtain the optimal sensing temperature. The fabricated NO2 gas sensor device based on PANI/Ag2O/GO composite exhibited a highest sensitivity of 5.85 for 25 ppm at an optimized temperature (100 °C) as compared to the pure PANI (2.5) and PANI/Ag2O composite (3.25). Further, the fabricated sensor device based on PANI/Ag2O/GO composite was also examined at different NO2 gas concentrations.

In this paper, pure SnO2 and Ce-doped SnO2 nanosheets were synthesized through a facile hydrothermal method. The synthesized materials were characterized by different techniques for their physico-chemical properties. The XRD data indicated the characteristic tetragonal rutile crystal phase for SnO2. Ce doping was ascertained by the presence of the diffraction peaks of CeO2 in all the doped samples of the SnO2 nanosheets. FESEM images revealed highly rough surfaces as well as the agglomeration of a large number of small nanoparticles of multiple shapes to form nanosheets like morphologies for pure SnO2 and Ce-doped SnO2. Electrochemical techniques like cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and chronoamperometry were applied to demonstrate the electrochemical performances of the pure SnO2 and Ce-doped SnO2 nanosheets/Nafion-modified glassy carbon electrode (GCE). The 3% Ce-doped SnO2 nanosheet/Nafion-modified GCE showed a remarkable sensitivity of 0.9986 μA μM−1 cm−2 over a linear dynamic range of 0.5–20.3 µM. The corresponding linear regression equation was Ip (μA) = 0.0709 [2-nitroaniline (μM)] + 0.1385 with R2 = 0.99325. The LOD of the modified sensor was found to be 6.3 ± 0.1 nM at the signal-to-noise ratio of S/N = 3. The newly developed sensor electrode exhibited good selectivity toward 2-nitroaniline in the presence of common interfering species. Fabrication and characterization of highly sensitive and selective 2-nitroaniline chemical sensor based on cerium-doped tin oxide nanosheets/Nafion-modified glassy carbon electrode.

Ethanol is one of the volatile organic compounds as well as organic pollutants that is essentially to be monitored using high response sensors. Semiconducting metal oxide nanostructures can be the potential sensor material for high-performance ethanol sensing application. Herein, we present the fabrication and characterization of highly sensitive and selective ethanol gas sensor based on flower-shaped CuO composed of thin nanoplates synthesized by facile hydrothermal process. The prepared flower-shaped CuO was examined by various techniques viz FESEM, XRD, EDS, elemental mapping, HRTEM, SAED, UV-visible spectroscopy, FTIR spectroscopy, and Raman spectroscopy, which confirmed the high-density growth, monoclinic crystal structure, and optical band gap of ~2.5 eV. The fabricated resistive sensor device based on flower-shaped CuO, at optimum experimental conditions, i.e., 250 °C, 100 ppm ethanol concentration, exhibited a high sensing response of 241%, while, at 10 ppm of ethanol concentration, the response was observed to be 5%. The transient responses as well as the stability of the sensor were analyzed and reported here. The selectivity of CuO sensor device was studied for NO2, CO2, CO, and CH4 gases and remarkably it was seen that the developed gas sensor devices demonstrated outstanding selectivity toward ethanol gas. Finally, the gas response mechanism of the fabricated resistive ethanol gas sensor was explained on the basis of the ionosorption model.

Methylene blue intercalated layered MnO2 nanosheets (MB-MnO2) were synthesized through an ex-situ method at room temperature. Tetramethylammonium hydroxide (TMAOH) was used as a delaminating agent for the synthesis of nanosheet-like structures of MnO2. The prepared nanocomposites were analyzed by various instrumental techniques such as UV–visible, FTIR, XRD, FESEM, and EDX for the close examination of the morphology, structure, shape, crystallinity, and vibrational characterization. Typical two-dimensional layer sheet-like morphologies with multiple folds were observed for non-intercalated MnO2, whereas intercalated MnO2 showed more flattered and planar square-shaped and elongated ultrathin sheet-like structures with occasional folds and crinkles. MB intercalated MnO2nanosheets were used as an efficient electron mediator for the electrooxidation of the ascorbic acid to dehydroascorbic acid. Cyclic voltammetry and chronoamperometry confirmed the excellent electrocatalytic activity of the modified MB intercalated MnO2 nanosheets/GCE over a wide range of ascorbic acid concentrations in 0.1 M PBS. The detection limit was computed to be 0.05 μM. The effect of the scan rates and concentration of the ascorbic acid were also analyzed.

Root like structured Ni-doped zinc oxide [Zn(1-x)NixO (x = 0.09)] thin films were deposited on a non-conducting glass substrate by indigenously developed spray pyrolysis system at optimized substrate hotness of 573±5 K. Thus obtained Ni-doped ZnO thin films were characterized by UV-visible spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Atomic Force Microscopy (AFM). XRD result revealed that Ni-doped ZnO has a polycrystalline nature with a hexagonal wurtzite structure. For pure ZnO and Ni-doped ZnO thin films, the particle sizes were 60.9 and 53.3 nm while lattice strain values were 1.56×10−3 and 1.14×10−3, respectively. The film surface showed characteristic root-like structure as observed by the SEM. It was observed that the Ni-doped ZnO thin films were grown in high density along with more extent of branching as compared to pure ZnO thin films but retained the root-like morphologies, however, the branches were more-thinner and of shorter lengths. AFM analysis showed that the surface grains of the Ni-doped samples are homogeneous with less RMS roughness values compared with the undoped ZnO samples. The photocatalytic activity of the prepared thin films was evaluated by the degradation of methyl orange (MO) dye under UV light irradiation. Pure ZnO and Ni-doped ZnO thin films took 150 min and 100 min to degrade about 60% MO dye, respectively.

ZnO–SnO2 nanocubes were used as promising material for efficient sensing of p-nitrophenol and faster photocatalytic degradations of dyes like methyl orange (MO), methylene Blue (MB) and acid orange 74 (AO74). ZnO–SnO2 nanocubes were prepared by the facile solution process at 50 °C using Zn(NO3)2·6H2O and SnCl2·2H2O as a precursor in the presence of ethylenediammine. The synthesized material was examined for its morphological, structural, crystalline, optical, vibrational, and compositional studies by using field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and photoluminescence spectroscopy. FESEM studies revealed the formation of well-defined ZnO–SnO2 nanocubes where the structural examinations revealed the formation of a crystalline tetragonal rutile phase for SnO2 with some crystal sites doped with Zn. The as-synthesized nanocubes were explored for their photocatalytic activities towards three different dye viz. MO, MB, and AO74. Practically, complete degradation of AO74 was seen within 4 minutes of photo-irradiation in the presence of 0.05 g ZnO–SnO2 nanocubes. However, 97.17% and 41.63% degradations were observed for MB and MO within 15 and 60 minutes, respectively. All the dye degradation processes followed the pseudo-first-order kinetic model. Moreover, the as-synthesized nanocubes were utilized to fabricate highly sensitive and selective fluorescent chemical sensor for the detection of p-nitrophenol (PNP). ZnO–SnO2 nanocubes showed a very low detection limit of 4.09 μM for the detection of PNP as calculated according to the 3σ IUPAC criteria. Further, the as-synthesized ZnO–SnO2 nanotubes were found to be highly selective for p-nitrophenol as compared to the other two isomers.

Nanostructured ZnO doped with different Ce precursor concentrations (1, 5 and 10 mol%) has been prepared via co-precipitation method and tested for their photocatalytic and chemical sensing performances toward methyl orange (MO) and picric acid (PA) chemicals, respectively. After addition of Ce dopant, the spherical morphology of ZnO particles changed to a cone-like structure and exhibited the single-phase wurtzite structure, except for the 10 mol % dopant concentration. Blue-shift was detected in 5 mol% Ce doping, and this was found to be the optimum concentration for achieving the maximum dye degradation and sensing performances. The 5 mol% Ce doped ZnO expressed the complete MO degradation under UV light illumination, but the decrease in MO degradation with 10 mol% Ce doped ZnO was suggested to suppress the Ce3+ character in the sample. Facile redox couple Ce3+/Ce4+ appeared to improve the charge separation of Ce-doped ZnO upon UV illumination, forming the basis for release of O2, leading to increased catalytic and PA sensing performances.

Implementing sensitive and fast ppb-level formaldehyde sensing at room temperature is still in extreme demand for practical indoor air quality monitoring. Herein, we developed a visible-light-sensitive and dipole-modified graphene-based nanocomposite ZnOx@ANS-rGO for ultrasensitive trace formaldehyde sensing. The rich oxygen vacancy zinc oxide (ZnOx) nanoparticles on graphene nanosheets provide OH-groups and edge sorption sites to facilitate the activation of adsorbed oxygen. Moreover, the supramolecular assembled 5-aminonaphthalene-1-sulfonic acid-modified graphene (ANS-rGO) nanosheets with donor–π–acceptor dipole served as an excellent conduction platform to transport and collect photo-generated electrons. Based on the collaboration of rich ZnOx and ANS-rGO, the obtained sensor ZnOx@ANS-rGO-0.1 showed the highest response (Ra/Rg = 1.58 to 1 ppm HCHO) among the MOS materials reported so far, and its limit of detection (LOD) can be as low as 5 ppb under 405 nm light illumination at RT. The outstanding efficiency and accuracy of the obtained gas sensor were confirmed by practical performance estimation in a 30 m3 chamber. The selectivity, long-term stability, repeatability and humidity resistance of the obtained sensors at RT were also revealed. The sensing mechanism based on the combination of visible-light activation and dipole modification was analyzed by the O-XPS, PL, in situ ATR-FTIR and charge density difference calculation.

Silicon substrate on-chip (SSOC) supercapacitors have recently attracted considerable attention in electronic devices because of their compatibility with the current silicon-based micro- and nanofa...

Herein, we report the facile solution phase precipitation synthesis of ZnO nanoparticles doped with various concentrations, i.e. 1, 5 and 10 mol% of lanthanum (La). The synthesized nanoparticles were characterized in detail by several techniques which confirmed the high-density growth and well-crystalline nature of La-doped ZnO nanoparticles. The XRD results revealed the successful incorporation of 1 mol% La ions in the hexagonal wurtzite structure of ZnO; however, small XRD peaks of La2O3 were detected in 5 and 10 mol% La-doped samples. All the La-doped nanoparticles were found to be UV responsive. For the application prospective, all the synthesized nanoparticles were used as photocatalyst for the photocatalytic degradation of three toxic dyes, i.e. methyl orange (MO), Rhodamine B (Rh B) dyes and picric acid (PA). By detailed photocatalytic investigations, interestingly, 1 mol% La-doped ZnO was found to be most efficient photocatalyst towards the degradation of all three organic dyes. Further, the synthesized nanoparticles were also used as fluorescent probe for the fluorescence sensing of picric acid (PA). Remarkably, the 1 mol% nanoparticles exhibited highest sensitivity, i.e. lowest limit of detection (LOD) value (1.05 µM L−1) towards PA compared to 5 and 10 mol% (1.38 µM L−1) La-doped ZnO nanoparticles.

Photocatalysts provide excellent potential for the full removal of organic chemical pollutants as an environmentally friendly technology. It has been noted that under UV-visible light irradiation, nanostructured semiconductor metal oxides photocatalysts can degrade different organic pollutants. The Sn6SiO8/rGO nanocomposite was synthesized by a hydrothermal method. The Sn6SiO8 nanoparticles hexagonal phase was confirmed by XRD and functional groups were analyzed by FT-IR spectroscopy. The bandgap of Sn6SiO8 nanoparticles (NPs) and Sn6SiO8/GO composites were found to be 2.7 eV and 2.5 eV, respectively. SEM images of samples showed that the flakes like morphology. This Sn6SiO8/rGO nanocomposite was testing for photocatalytic dye degradation of MG under visible light illumination and excellent response for the catalysts. The enhancement of photocatalytic performance was mainly attributed to the increased light absorption, charge separation efficiency and specific surface area, proved by UV-vis DRS. Further, the radical trapping experiments revealed that holes (h+) and superoxide radicals (·O−2) were the main active species for the degradation of MG, and a possible photocatalytic mechanism was discussed.

Herein, we report the facile synthesis, characterization and visible-light-driven photocatalytic degradation of perforated curly Zn0.1Ni0.9O nanosheets synthesized by hydrothermal process. The X-ray diffraction (XRD) and scanning electron microscopy (SEM) studies confirmed the cubic phase crystalline structure and growth of high density perforated curly Zn0.1Ni0.9O nanosheets, respectively. As a photocatalyst, using methylene blue (MB) as model pollutant, the synthesized nanosheets demonstrated a high degradation efficiency of ~76% in 60 min under visible light irradiation. The observed results suggest that the synthesized Zn0.1Ni0.9O nanosheets are attractive photocatalysts for the degradation of toxic organic waste in the water under visible light.

Herein, we report the facile microwave-assisted synthesis, characterization and photocatalytic degradation applications of Bismuth ferrite heterostructures composed of interconnected nanosheets (BHNs). The synthesized materials were subjected to several analytical studies such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), Fourier transform infrared (FTIR) spectroscopy and UV-visible spectroscopy in order to examine the morphological, structural, optical and photo catalytic properties. The structural and morphological characterizations confirmed the rhombohedral perovskite crystal structure and the formation of heterostructures composed of interconnected nanosheets for the synthesized material. The compositional characterization revealed that the synthesized material is bismuth ferrite with high purity. The BHNs were further used as efficient photocatalyst for the photocatalytic degradation of highly hazardous pollutant methyl orange under sunlight irradiation. The sunlight driven photocatalytic experiments revealed ~86% photodegradation of methyl orange dye in 150 min. The presented work revealed that the synthesized BHNs are excellent material for the photocatalytic degradation of various organic contaminants and hazardous pollutants.

Herein, we report the synthesis and analysis of fern shaped La2O3 nanostructures as potential scaffolds for efficient hydroquinone chemical sensing application. A facile, low-cost hydrothermal method was applied for the synthesis of 3D fern shaped La2O3 nanostructures. Several techniques were employed to characterize the synthesized La2O3 nanostructures. XRD analysis confirmed the hexagonal phase for the La2O3 nanostructures with an average crystallite size of 35.18 nm. FESEM and TEM analysis established the 3D fern shaped structures for La2O3 nanostructures with dendritic arms of different lengths alongside triangular-ovate outlines. Purity, composition and vibrational features were confirmed by EDS, FTIR and Raman spectroscopic studies. The fabricated 3D fern shaped La2O3 nanostructures modified glassy carbon electrode (GCE) showed remarkable electron mediating properties towards hydroquinone even at very low analyte concentrations. The linear dynamic range (LDR), experimental limit of detection (LOD) and sensitivity for 3D fern shaped La2O3 nanostructures modified GCE in phosphate buffer solution (PBS) were found to be 0.0781–0.625 mM, 0.0781 mM and 463.3 μA mM−1cm−2, respectively. Finally, a mechanism was also proposed for the electrochemical sensing of the hydroquinone. The presented work thus, confirms that the 3D fern shaped La2O3 nanostructures may be the future potential candidates for fabricating efficient and reproducible electrochemical sensors.

Herein, we report a simple synthesis, characterization and photocatalytic degradation application of composite NiO-WO₃ nanoparticles. The nanoparticles were synthesized by facile low-temperature method and characterized by several techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV-Vis diffuse reflectance spectra (DRS). The synthesized NiO-WO₃ nanoparticles were used as efficient photocatalyst for the photocatalytic degradation of Eosin yellow (EY) dye. Interestingly, the synthesized photocatalytic exhibited a significant visible-light driven photocatalytic degradation of Eosin yellow (EY) dye. Under optimized conditions (pH = 5, catalyst dosage = 3 μM and initial dye concentration= 1.0 g/L), the obtained photo degradation of EY dye was above 95% in 180 min under visible light irradiation. Remarkably, reusability of the prepared photocatalyst was also observed and the photo-degradation reactions follow the pseudo-first-order model.

Herein, we report the facile synthesis of Iron oxide@Pt core-shell nanoparticles (NPs) by facile two step synthesis process. The first step follows the growth of iron oxide nanoparticle by thermal decomposition process while the second step deals with the formation of iron oxide@Pt core-shell nanoparticles by the chemical reduction method. The synthesized core-shell nanoparticles were characterized by several techniques and used for the catalytic reductive translation of Cr(VI) to Cr(III) in the presence of formic acid by a UV-vis spectrophotometer. The UV photo-spectrometer analysis confirmed the conversion efficiency from 12% to as high as 98.8% at the end of 30 minutes. Thus, the presence of Iron oxide @Pt core-shell nanoparticles (NPs) can be effectively used as a catalyst for the reducion of Cr(VI) to Cr(III) ions. Additionally, antibacterial studies were performed for the prepared core-shell nanoparticles against two bacterial strains, i.e., gram (+ve) Staphylococcus Aureus (S. Aureus) and gram (-ve) Escherichia Coli (E. Coli).

We demonstrate the preparation of nanostructures cobalt oxide/reduced graphene oxide (Co3O4/rGO) nanocomposites by a simple one-step cost-effective hydrothermal technique for possible electrode materials in supercapacitor application. The X-ray diffraction patterns were employed to confirm the nanocomposite crystal system of Co3O4/rGO by demonstrating the existence of normal cubic spinel structure of Co3O4 in the matrix of Co3O4/rGO nanocomposite. FTIR and FT-Raman studies manifested the structural behaviour and quality of prepared Co3O4/rGO nanocomposite. The optical properties of the nanocomposite Co3O4/rGO have been investigated by UV absorption spectra. The SEM/TEM images showed that the Co3O4 nanoparticles in the Co3O4/rGO nanocomposites were covered over the surface of the rGO sheets. The electrical properties were analyzed in terms of real and imaginary permittivity, dielectric loss and AC conductivity. The electrocatalytic activities of synthesized Co3O4/rGO nanocomposites were determined by cyclic voltammetry and charge-discharge cycle to evaluate the supercapacitive performance. The specific capacitance of 754 Fg-1 was recorded for Co3O4/rGO nanocomposite based electrode in three electrode cell system. The electrode material exhibited an acceptable capability and excellent long-term cyclic stability by maintaining 96% after 1000 continuous cycles. These results showed that the prepared sample could be an ideal candidate for high-energy application as electrode materials. The synthesized Co3O4/rGO nanocomposite is a versatile material and can be used in various application such as fuel cells, electrochemical sensors, gas sensors, solar cells, and photocatalysis.

A tetraphenylethylene (TPE) derivative (N,N-dimethyl-N′-(4-(1,2,2-triphenylvinyl)phenyl)acetimidamide, TPE-amidine) was designed and synthesized, and used to prepare visible CO2 chemosensors, TPE-amidine-L (liquid) and TPE-amidine-S (solid). The hydrophilicity of TPE-amidine thoroughly changed because of the unique reversible reaction between the amidine group and CO2, which controlled the molecular aggregation extent in water by CO2. Combining with the well-known aggregate-induced emission effect, the highly selective CO2 chemosensor TPE-amidine-L was developed, which has the lowest CO2 detection limit of 24.6 ppm compared with other reported CO2 chemosensors, and can be regenerated within 10 s by adding triethylamine. With the aim of being safer and more convenient to use, a polyacrylamide hydrogel containing TPE-amidine was prepared as a renewable CO2 sensing “tape” (TPE-amidine-S). The flexibility, adhesivity, CO2 sensitivity and reversibility of the “tape” is systematically investigated, showing great potential for “on-site” and “real-time” CO2 detection in practical applications.

This review seeks to explore the literature pertaining to the applicability of nano-photocatalysts in fine chemical synthesis of organic compounds. The current methods of preparation of organic compounds in laboratories and industries are highly demanding on the non-renewable sources of energy. These conventional methods also generally require extreme conditions of temperature and pressure. Owing to deeper global awareness toward conservation of non-renewable sources of energy, there has been a shift of focus toward photocatalysis in the recent years. Photocatalysts are long known to catalyze various organic reactions such as oxidation, reduction, addition, cyclization and decomposition. The advent of nanotechnology made it possible to scale down these photocatalytic materials from bulk- to nano-scale and thereby further widen their scope and efficiency. Advances in material chemistry and nanotechnology have also made it possible to synthesize nanophotocatalysts of new genres, properties of which can be controlled and designed at molecular level. In this review, an attempt has been made to classify these diverse nanophotocatalysts into different groups, based on their composition and mechanism. Since the literature survey revealed that the chemoselectivity and efficiency of the nanophotocatalysts depend on their method of preparation, an overview of their common synthesis protocols is included. The review also highlights the various organic conversions for which these nanomaterials can be used under UV/visible irradiation. Nanophotocatalysts hold a great promise for environmentally-benign synthesis of highly useful organic compounds. We believe that this review can provide insights into research done in this field so far, which can pave way for further progress in this topic of far-fetched social significance. Keywords: Photocatalysis, Nano-photocatalysis, Organic synthesis, Green Chemistry, Photosensitization

Herein, we report the enhanced solar light-mediated photocatalytic degradation of brilliant green dye using BiPO4 nanospindles and MoS2/BiPO4 nanorods synthesized by facile hydrothermal process. The synthesized nanomaterials were examined by various techniques such as X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy (TEM) attached with energy dispersive X-ray spectroscopy, Brunauer–Emmett–Teller, and pore size distribution analysis. The detailed characterizations revealed that after the introduction of MoS2, the crystalline phase transformation from hexagonal to monoclinic was observed for BiPO4. The TEM images clearly confirmed that BiPO4 possessed nanospindles and MoS2/BiPO4 exhibited nanorod-shaped morphologies. The photocatalytic activity of synthesized MoS2/BiPO4 nanorod heterojunction was explored for the degradation of brilliant green (BG) dye under solar light irradiation. Interestingly, approximate 80% degradation of BG was observed under solar light in 70 min using MoS2/BiPO4 nanorods as photocatalyst. As an efficient photocatalyst, the synthesized MoS2/BiPO4 nanorod heterojunction exhibited enhanced photocatalytic efficiency as compared to pure BiPO4 nanospindles, commercially available TiO2PC-50 and TiO2 PC-500 under solar light. The high photocatalytic activity of MoS2/BiPO4 nanorod heterojunction could be related to the amended visible light-harvesting tendency, effective charge separation, and facile transportation of photogenerated e−/h+ pairs at the heterojunction interface.

Well crystalline Ag/CeO2 nano-structured material being utilized for its photocatalytic and antibacterial activities was synthesized via simple solution combustion synthesis (SCS) approach using tartaric acid as a fuel. Interconnection of Ag with CeO2 was investigated to determine its morphological, structural, crystalline, surface and optical properties using common characterization tools. The synthesized Ag–CeO2 materials are of high purity and well-crystalline, having a porous nature with an average pore size of ∼5–7 nm. As-synthesized Ag–CeO2 materials were utilized as photocatalyst for catalytic Rhodamine B (RhB) dye degradation under UV irradiation, showing the almost full degradation of RhB dye molecules in 150 min. As-synthesized Ag/CeO2 nanostructured materials were also investigated for their antibacterial activity toward gram positive (S. aureus) and gram negative (P. aeruginosa) strains of bacteria. The minimum inhibitory concentration for inhibiting the growth of S. aureus (gram positive) and P. Aureginosa (gram negative) were found to be 3.125 μg/ml and 6.25 μg/ml in the presence of Ag/CeO2 materials. The results obtained for Ag/CeO2 materials clearly displayed the significantly improved catalytic and antibacterial properties in comparison with pure CeO2.

Herein, we report the successful synthesis of different phases of VO2 nanomaterials via a facile hydrothermal method by simply varying the molar ratio of the reducing agent (citric acid monohydrate) to vanadium precursor (vanadium (V) oxide). Six samples were synthesized with corresponding variation in molar ratio of vanadium (V) oxide to citric acid monohydrate as 1:1, 1:1.5, 1:2, 1:3, 1:4 and 1:5, respectively. The synthesized nanomaterials were characterized by phase identification, morphologies, compositional, optical, thermal, and electrical properties. The detailed characterizations confirmed the formation of single phase VO2 (B), VO2 (M) and amorphous VO2 by the mere variation of relative concentrations of reducing agent. Even though the synthesis of single phase VO2 is challenging and interestingly, a simple, one-step hydrothermal process procedure was used to produce pure phaseVO2 without the use of inert environment or post-synthesis heat treatments.

Carbon dioxide (CO2), an important gas molecule metabolite produced by the tricarboxylic acid cycle, is a direct signal for identifying cancers in cells and tissues. Herein, design and synthesis of a novel "breathable" block polymer supramolecular assembly probe consisting of a hydrophilic block, an amidine-containing CO2-responsive block, and an aggregation-induced emission (AIE) luminescence block to detect CO2 metabolized by cancer cells is reported. The triblock copolymer poly-(4-undecoxy tetraphenyl ethylene methacrylate)-b-poly-((N-amidino)-(2,3-dihydro-1H-1, 4-methyl-1, 2,3-triazole)-(ethenylbenzene))-b-poly(ethylene oxide) (PTPE-b-PAD-b-PEO) was successfully synthesized and characterized. This triblock copolymer could be self-assembled into "breathable" aqueous solution vesicles. In the presence of CO2, the amidine-containing CO2-responsive block (PAD block) of the vesicle "inhales" an amount of CO2, which causes the volume of the vesicle to expand. The expansion of the vesicle induces the aggregation of the AIE luminescence block (PTPE block), which resulted in the fluorescence intensity enhancement. The supramolecular vesicles "exhale" CO2, and the volume and AIE phenomenon of the vesicles decrease when N2 is passed into the solution. On the basis of this reversible change of fluorescence intensity, HeLa cervical cancer cells, CNE1 nasopharynx cancer cells, 5-8F nasopharynx cancer cells, 16HBE human bronchial epithelial cells, and GES-1 human gastric mucosa epithelial cells have all been successfully detected and identified.

Special functional groups to modify the surface of graphene have received much attention since they enable the charge transfer enhancement, thus realizing gas-sensing at room temperature. In this work, three typical redox dye molecules, methylene blue (MB), indigo carmine (IC) and anthraquinone-2-sulfonate (AQS), were selected to be supramolecularly assembled with reduced graphene oxide (rGO), respectively. Remarkably, three graphene-based materials AQS-rGO (response = 3.2, response time = 400 s), IC-rGO (response = 4.3, response time = 300 s) and MB-rGO (response = 7.1, response time = 100 s) exhibited excellent sensitivity and short response time toward 10 ppm NO2 at room temperature. The corresponding NO2 sensing mechanism of the obtained materials was further investigated by cyclic voltammetry (CV) measurements. CV was conducted to measure the anodic peak potential (Epa) of three redox dyes. Interestingly, it is obvious that the Epa values were positively correlated with the gas sensitivity and response time of the three materials. To explore the mechanism, UV–vis spectroscopy was adopted to analyze the lowest unoccupied molecular orbitals (LUMOs) of three redox dye molecules. The results show that the oxidation abilities of three redox dyes were also positively correlated with the gas sensitivity and response time of three corresponding graphene-based materials.

Herein, we have developed a novel sensing electrode to detect the eco-toxic 4-nitrophenol (4-NP). Ag-doped-ZnO nanoflowers were synthesized by facile hydrothermal method and examined by several characterization techniques in order to understand the morphology, crystal structure, composition, and surface properties. Morphological results were confirmed by the formation of Ag-doped ZnO nanoflowers decorated with nanosheets. Ag-doped ZnO/glassy carbon electrode (GCE) electrode-material-matrix was used for electrochemical sensing of toxic 4-NP. Under optimized conditions, Ag-doped ZnO/GCE modified electrode exhibits high-sensitivity and selectivity compared to the bare GCE electrode. The Ag-doped ZnO/GCE modified electrode exhibits high electrocatalytic oxidation towards 4-NP. Anodic peak current of 4-NP is increased linearly by increasing the concentration of nitrophenol. Additionally, Ag-doped ZnO/GCE shows a wide range of sensitivity from 10 µM to 500 µM, and a linear calibration plot with a good detection limit of 3 µM (S/N = 3). The proposed Ag-doped ZnO/GCE modified electrode showed high sensing stability. In addition, the oxidation mechanism was studied. The obtained results revealed that the Ag-ZnO/GCE electrode could be the promising sensing electrode for 4-NP sensing.

Herein, we report a chemi-resistive sensing method for the detection of formaldehyde (HCHO) gas. For this, α-MnO2 nanowires were synthesized hydrothermally and examined for ascertaining their chemical composition, crystal phase, morphology, purity, and vibrational properties. The XRD pattern confirmed the high crystallinity and purity of the α-MnO2 nanowires. FESEM images confirmed a random orientation and smooth-surfaced wire-shaped morphologies for as-synthesized α-MnO2 nanowires. Further, the synthesized nanowires with rounded tips had a uniform diameter throughout the length of the nanowires. The average diameter of the α-MnO2 nanowires was found to be 62.18 nm and the average length was ~2.0 μm. Further, at an optimized temperature of 300 °C, the fabricated HCHO sensor based on α-MnO2 nanowires demonstrated gas response, response, and recovery times of 19.37, 18, and 30 s, respectively.

A label free electrochemical sensor based on pure titanium oxide and manganese (Mn)-doped titanium oxide (TiO2) nanoparticles are fabricated and characterized for the sensitive detection of myoglobin (Mb) levels to analyze the cardiovascular infarction. Pristine and Mn-doped TiO2 nanoparticles were synthesized via the sol-gel method and characterized in order to understand their structure, morphologies, composition and optical properties. The structural properties revealed that the pure- and doped-TiO2 nanoparticles possess different TiO2 planes. FTIR studies confirm the formation of metal oxide nanoparticles by exhibiting a well-defined peak in the range of 600–650 cm−1. The values of the optical band gap, estimated from UV-Vis spectroscopy, are decreased for the Mn-doped TiO2 nanoparticles. UV-Vis spectra in the presence of myoglobin (Mb) indicated interaction between the TiO2 nanoparticles and myoglobin. The SPE electrodes were then fabricated by printing powder film over the working electrode and tested for label-free electrochemical detection of myoglobin (Mb) in the concentration range of 0–15 nM Mb. The fabricated electrochemical sensor exhibited a high sensitivity of 100.40 μA-cm−2/nM with a lowest detection limit of 0.013 nM (0.22 ng/mL) and a response time of ≤10 ms for sample S3. An interference study with cyt-c and Human Serum Albumin (HSA) of the sensors show the selective response towards Mb in 1:1 mixture.

In the present research work, 2D-Porous NiO decorated graphene nanocomposite was synthesized by hydrothermal method to monitored the concentration of epinephrine (EPI). The morphology (SEM and TEM) results confirmed 2D-Porous NiO nanoparticles firmly attached over graphene nanosheets. FTIR and XPS analysis confirmed the formation of nickel oxide formation and complete reduction of GO to rGO. The electrochemical activity of the proposed NiO-rGO/GCE modified electrode on epinephrine was analyzed by simple cyclic voltammetry technique. The proposed low cost NiO-rGO/GCE modified electrode showed excellent catalytic activity over GCE and rGO/GCE electrodes. Due to its high conductivity and charge transfer ability of the NiO-rGO/GCE modified electrode exhibited high sensitivity of EPI at optimized conditions. The anodic peak current of the EPI linearly increases with increasing the concertation of EPI. A wide linear range (50 μM–1000 μM) was achieved with high correlation coefficient (R2 = 0.9986) and the limit of detection (LOD) of NiO-rGO/GCE modified electrode was calculated to be 10 μM. NiO-rGO/GCE electrode showed good stability and repeatability towards the EPI oxidation. Mainly, the proposed NiO-rGO/GCE modified electrode showed good sensitivity of EPI in the human biological fluid with high recovery percentage. The low cost, NiO-rGO/GCE electrode could be the promising sensor electrode for the detection of Epinephrine in the real samples.

This paper reports synthesis, properties and gas sensing applications of ZnO nanoflowers and CdO–ZnO nanorices prepared by hydrothermal process. The morphological characterizations confirmed the formation of well-defined nanoflowers and nanorices structures for ZnO and CdO–ZnO nanomaterials, respectively. The structural properties revealed the wurtzite hexagonal phase of the synthesized materials. The sensor devices based on ZnO nanoflowers and CdO–ZnO nanorices were fabricated and tested towards various gases including ethanol, methanol, ammonia, carbon monoxide, methane and formaldehyde. The fabricated gas sensor based on CdO–ZnO nanorices exhibited a high response (34.5) towards 300 ppm formaldehyde gas at 350 °C compared to ZnO nanoflowers (14.5) under the same experimental conditions. The response and recovery times for ZnO nanoflowers-based sensor were~9.8 s and ~6 s while for CdO–ZnO based sensor, these were ~10s and ~6s, respectively. A rapid response (34.5) for CdO–ZnO nanorices based formaldehyde gas sensor was observed as compared to other gases such as ammonia (12.3), methanol (16.5), ethanol (20), carbon monoxide (16.3) and methane (12.4), which confirm the high-selectivity towards formaldehyde gas. Finally, a plausible formaldehyde gas sensing mechanism is proposed.

Here, we report the biogenic preparation of luminescent copper oxide (CuO) nanoparticles via peel extracts of Musa acuminate. The current methodology provides the sustainable alternative of using agricultural fritter as effective stabilizing and reducing agent during the synthesis of CuO particles. The parameters governing the optimization of CuO nanoparticles were scrutinized by varying the concentrations of copper salt, stirring rate and pH of the reaction media. The toxicity profiling of CuO nanoparticles over the germination of Vigna radiate. Allium cepa genotoxicity and antibacterial assay were also examined to verify the biocompatibility of prepared CuO particles. The in-vitro biocompatibility of the developed nanoparticles was tested against mouse L929 fibroblastic cell lines by using MTT assay in range of 1–80 μg/mL. The distinctive optical and luminescence properties have been employed for sensing application for heavy metal ions using UV–vis. and fluorescence spectrophotometric analysis. The value of detection of limit for the developed sensor was found to be 2 μg/L. The low values of detection limits facilitate the practical utilization of CuO nanoparticles for sensing applications. As prepared CuO nanoparticles can act as a biocompatible fluorophore nominee to substitute existing dyes. The current study provides the additional advancement towards the sensing of toxic metal using green and safe CuO nanoparticles.

This study reports the biosynthesis of silver nanoparticles (AgNPs) using methanolic leaf extract of Pogostemon cablin Benth. (Patchouli) as a reducing agent, and their potent biological (antibacterial, antioxidant and anticancer) activities. The P. cablin extract when exposed to silver nitrate reduced silver ions to form crystalline AgNPs within 1 h of incubation at room-temperature. UV-visible spectra showed a sharp surface plasmon resonance (SPR) at around 430 nm for the biosynthesized AgNPs and the XRD pattern indicated the crystalline planes of the face centered cubic silver. The FE-SEM analysis revealed the occurrence of predominant spherical shaped AgNPs with a huge disparity in their particle size distribution with an average size of 25 nm, while, the FTIR data confirmed the bio-reduction and capping of AgNPs by several phytocompounds present in the methanolic leaf extract. AgNPs effectively inhibited the growth of all the tested human pathogenic bacterial strains (Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli), while, the methanolic leaf extract failed to inhibit the growth of S. aureus and P. aeruginosa. AgNPs showed the highest free radical scavenging activity (79.0 ± 0.76%) compared to methanolic leaf extract (68.3 ± 0.68%) at 100 μg/ml. Further, the cytotoxicity study using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) confirmed that AgNPs successfully inhibited the human colon adenocarcinoma cell line (HT-29) in a dose dependent manner. At higher concentrations (500 μg/ml), only 4% of cells survived after 72 hrs of exposure with IC50 value of 120 μg/ml. Thus, these findings offer a new source of biomolecules with diverse biological activities.

Herein, we report the synthesis, characterization and picric acid chemical sensing application of samarium (Sm) doped ZnO nanorods. The Sm-doped ZnO nanorods were synthesized by facile hydrothermal process and characterized using various analytical methods which confirmed the large-scale synthesis and wurtzite hexagonal crystal structure for the synthesized nanorods. The doping of Sm ions in the lattices of the synthesized nanorods was evaluated by the energy dispersive X-ray spectroscopy (EDS). The synthesized Sm-doped ZnO nanorods were used as potential scaffold to fabricate high sensitive and reproducible picric acid chemical sensor based on I–V technique. The fabricated picric acid chemical sensor based on Sm-doped ZnO nanorods exhibited a high sensitivity of 213.9 mA mM−1 cm−2 with the limit of detection of ∼0.228 mM and correlation coefficient of R═0.9889. The obtained results revealed that the facile grown Sm-doped ZnO nanorods can efficiently be used to fabricate high sensitive and reproducible chemical sensors.

Recently, because of excellent electrical conductivities and many active sites, transition metal sulfides have been utilized as efficient electrodes for supercapacitors. Herein, we synthesize hierarchical MoS2/Ni3S2 structures grown on nickel foam by a facile one-pot hydrothermal process. The as-fabricated asymmetric hybrid capacitor based on hierarchical MoS2/Ni3S2 electrode exhibit a specific capacitance of ∼1.033 C/cm2 at 1 mA/cm2. Furthermore, the hybrid capacitor unveils an energy density of 35.93 mWh/cm3 at a power density of 1064.76 mW/cm3. The observed results clearly revealed that the synthesized MoS2/Ni3S2 structure might be used as potential electrode material for future energy storage devices.

Herein, we report the synthesis and characterization of rGO-CdS heterostructure and their utilization as an efficient material for sensing and visible-light driven photocatalytic degradation applications. The heterostructure was synthesized by facile hydrothermal process and characterized by several techniques which exhibited intriguing compositional, morphological, structural, thermal, textural and photo-physical properties. The high resolution transmission electron microscopy (HRTEM) images of the prepared rGO-CdS heterostructure showed the successful deposition of CdS nanoparticles (CdS NPs) on the surface of reduced graphene oxide (rGO) sheets. The synthesized rGO-CdS heterostructure was employed as an outstanding fluorescent sensor for the selective and sensitive detection of heavy transition metal ion; Ag(I) and a synthetic food colorant; sunset yellow (SY). The detection limit of 12.35 μM and 7.89 μM was found to be for Ag(I) and SY, respectively. The prepared rGO/CdS heterostructure was also successfully applied for the photocatalytic degradation of fluoroquinoline antibiotic, levofloxacin (LVX), and food colorant SY under visible-light irradiation. The removal efficiency of 82.7% was obtained for LVX (10 mg/L) using rGO-CdS heterostructure in 60 min under visible-light irradiation. The synthesized heterostructure displayed enhanced photocatalytic decomposition (82.7%) than pure CdS NPs (67.5%) under optimized reaction conditions (0.50 g/L photocatalyst amount, 10 mg/L LVX initial concentration and pH 9.0). Approximate 66% of SY was degraded in 270 min under visible-light using the prepared heterostructure. The scavenger study confirmed the pivotal role of e, O2 , OHs and OH in the photocatalytic decomposition process. The amended photocatalytic behaviour of the rGO-CdS heterostructure could be accredited to the enhanced visible light harvesting capability, effective charge separation and transportation of photogenerated charge carriers across the heterojunctional interface. To the best of our knowledge, this is the first report till date on the utilization of rGO-CdS heterostructure for the fluorescence sensing of Ag(I) and SY as well as photocatalytic degradation of LVX and SY.

Developing biomaterials based on the natural biomacromolecule silk sericin from Bombyx mori cocoon is of great interest for biomedical application. Dialdehyde carboxymethyl cellulose (DCMC) is derived from periodate oxidation of carboxy- methyl cellulose. Here, we developed a novel strategy of cross-linking of sericin with DCMC via the Schiff's base reaction. Fourier transform infrared spectroscopy and scanning electron microscopy indicated the formation of Schiff's base via the blending of sericin and DCMC. The mechanical properties tests suggested the covalent cross-linking effectively enhanced the tensile strength of sericin. The swelling test and water contact angle indicated the DCMC/SS film had excellent hydrophilicity, swellability. Additionally, we demonstrated the DCMC/SS film had excellent blood compatibility, cytocompatibility and promoting cell proliferation activity by the hemolysis ratio analysis, cell adhesion, cells viability and proliferation assays. The prepared DCMC/SS film has shown great promise in biomedical applications such as wound dressing, artificial skin and tissue engineering.

Herein, we report the successful synthesis of BiF3 octahedrons via facile hydrothermal process as potential solar light active catalyst for the photocatalytic degradation of Rhodamine B (RhB) dye in aqueous phase. The synthesized BiF3 octahedrons were characterized by several techniques such as X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), Fourier transform infrared (FT-IR) spectroscopy, UV-diffuse reflectance spectroscopy (UV-DRS), photoluminescence (PL) spectroscopy, thermogravimetric analysis (TGA) and Brunauer-Emmett-Teller (BET) techniques in order to observe the structural, morphological, optical and luminescence properties. The synthesized octahedrons possess the high density growth, pure and well-crystalline with cubic phase structure and band gap of 3.98 eV. As a potential solar light active photocatalyst , the synthesized BiF 3octahedrons exhibited ˜95.7% degradation of RhB in 50 min. The effect of different process parameters such as pH and catalyst dose on the degradation of RhB was also explored. Interestingly, the synthesized BiF3 octahedrons demonstrated better photocatalytic performance compared to several commercially available photocatalysts such as TiO2 (PC-500), SnO2 and ZnS. Further, it was observed that the degradation of RhB over the prepared BiF3 octahedrons obeyed the pseudo first-order reaction kinetics with rate constant of 0.06393 min−1. The scavenger experiments verified the role of h+, e, O2 , OH and OHs in the photocatalytic degradation process and a plausible photocatalytic mechanism has also been proposed.

Reduced graphene oxide modified by hyperbranched polyamine-ester (RGO-HBPE) liquids was successfully fabricated through the surface chemical engineering and tested for serving as a solvent-free novel lubricant. Structural characterization, dispersibility and rheology behavior of the lubricant and the related frication performance on steel plate were investigated thoroughly. The results manifest that the RGO-HBPE exhibited good dispersity in distilled water and liquid behavior without any solvent at ambient temperature. And this RGO-HBPE liquids could be directly introduced onto the surface of steel plate as lubricants without any additional base oil. Tribological results and the proposed lubricating mechanism of RGO-HBPE imply that the fluidity of RGO-HBPE is favorable for lubrication and is crucial to reduce the friction coefficient. The spontaneous flow of RGO-HBPE provide a spreading effect to form the lubricating film. The specific spreading effect of RGO-HBPE and the synergistic lubricating effect between HBPE and graphene demonstrate that RGO-HBPE could be directly used as promising candidates for lubricants in nowadays moving machines.

Herein, we report the synthesis, characterization and enhanced adsorption studies of porous octahedral shaped Cu-BTC (copper benzene-1,3,5-tricarboxylate) metal organic frameworks (MOFs). The Cu-BTC MOFs were synthesized by facile hydrothermal process and characterized by various techniques in order to examine the structural, morphological, thermal and adsorption-desorption properties. The synthesized Cu-BTC MOFs were used as potential scaffold for the adsorption of highly toxic azo dye, i.e. methylene blue (MB). Detailed adsorption studies on the effect of initial pH, concentration, reaction time and temperature on adsorption of MB were analysed and it was observed that the removal of MB followed pseudo-2nd order kinetic model. Freundlich model fitted well as compared to Langmuir model with R2 of 0.975 and thereby signifying a multilayer adsorption of MB on the surface of Cu-BTC MOFs. The observed maximal adsorption capacity for MB removal (200 mg/L) was ∼101.21 mg/g using Langmuir isotherm. The Cu-BTC MOFs exhibited 42.3 mg/g adsorption capacity after fourth cycle of MB dye adsorption. These features exhibited that Cu-BTC MOF have potential for the adsorption of MB and can efficiently be used to treat wastewater.

Molybdenum disulfide (MoS2) is an extremely promising electrode material for supercapacitors due to its superior electrochemical performance and conductivity. In this study, polypyrrole (PPy) modified MoS2/Ni3S2 (MNS@PPy) assemblies grown directly on the Ni foam (NF) substrate are prepared by a facile hydrothermal route and a subsequent electrodeposition process. The as-obtained products show a specific capacitance of 845 C g−1 at 1 A g−1 with outstanding cycling stability after 10 000 cycles. Using the as-synthesized products as positive materials, an assembled hybrid capacitor delivers an energy density of 280.5 W h kg−1 at a power density of 2845 W kg−1, demonstrating its promising application in portable micro-/nanoscale energy storage devices.

This paper explains the preparation of SnO2-Sb2O3 composite catalyst by solid state reaction process, and posteriorly employs as an alternative and promising photocatalyst for Brilliant Green (BG) dye degradation under solar irradiation. SnO2 and Sb2O3 composite samples with varying proportions of SnO2 and Sb2O3 were created, with 2 to 5 w t% SnO2 added to the Sb2O3 sample. The synthesized samples were characterized by X-ray powder diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectrometry (EDS) and UV-visible diffuse reflectance spectroscopy (DRS). The results showed that the 3% SnO2-Sb2O3 sample presented higher catalytic activity compared to the others, besides SnO2 and Sb2O3 alone, reaching ~90% of decolonization and ~87% of COD removal at 180 min. This remarkable photocatalytic activity may be associated to its favorable band gap energy. Kinetic data fitted well with pseudo-first-order kinetic model. Therefore, the SnO2-Sb2O3 composite prepared in this work can be considered as an effective photocatalyst for elimination of colored-contaminants, such as BG dye, from wastewater.

The scarcity of available drinking water has led the researchers to develop novel and cost-effective ways of bioremediation process for wastewater treatment. Bioremediation is a cost-effective and environmentally sound method for the removal of toxic compounds. Such approach is not only a chemical-less effort but also an energy savior. In the present work Phlebia acerina, a white rot wood rotting fungi have been used to degrade the toxic wastewater pollutants. Congo Red (CR) and Eriochrome Black T (EBT) have been selected as model pollutants to test the wastewater cleaning ability of the fungus. The Lignin modifying enzyme (LME) and Cellulolytic enzyme assays (CMC) potential of Phlebia acerina helped in understanding the dye degradation mechanism. Under the optimum conditions, the fungi was able to degrade as high as 92.4% CR while the EBT was degraded to a maximum of 50%. Phlebia acerina was found to show first-order kinetics of dyes degradation. Further, the seed germination and antimicrobial assay of treated and untreated water were carried out in order to establish the formation of non-toxic end product after degradation.

We report on the electrical properties of natural p-type GeSe nanoflakes, which were mechanically exfoliated from GeSe single crystals by the polydimethylsiloxane (PDMS) stamp method, using a back-gate field effect transistor (FET) measured in a vacuum probe station at room temperature. In this study, we used two contact metals, including Au and Cr metals, as the Ohmic contacts to the GeSe nanoflake FETs, resulting in an Ohmic behavior with the Au contacts, with a total resistance of 5.5 × 106 Ω. We also found that the 40-nm-thick GeSe nanoflake FET exhibits clear p-type semiconductor behavior with a field-effect mobility of ∼1.0 × 10–3 cm2/(V · s) and a current on/off ratio of ∼104 at room temperature.

Regenerative medicine is a field that aims to influence and improvise the processes of tissue repair and restoration and to assist the body to heal and recover. In the field of hard tissue regeneration, bio-inert materials are being predominantly used, and there is a necessity to use bioactive materials that can help in better tissue–implant interactions and facilitate the healing and regeneration process. One such bioactive material that is being focused upon and studied extensively in the past few decades is bioactive glass (BG). The original bioactive glass (45S5) is composed of silicon dioxide, sodium dioxide, calcium oxide, and phosphorus pentoxide and is mainly referred to by its commercial name Bioglass. BG is mainly used for bone tissue regeneration due to its osteoconductivity and osteostimulation properties. The bioactivity of BG, however, is highly dependent on the compositional ratio of certain glass-forming system content. The manipulation of content ratio and the element compositional flexibility of BG-forming network developed other types of bioactive glasses with controllable chemical durability and chemical affinity with bone and bioactivity. This review article mainly discusses the basic information about silica-based bioactive glasses, including their composition, processing, and properties, as well as their medical applications such as in bone regeneration, as bone grafts, and as dental implant coatings.

Herein, room-temperature NO2 gas sensor based on supramolecularly assembled isonicotinamide–graphene oxide nanocomposite (Iso-rGO) and Iso-rGO/Carbon felt (CF) electrode was prepared and studied. The morphology of the synthesized Iso-rGO nanocomposite was studied by field emission scanning electron microscopy (SEM), which revealed the uniform coating of isonicotinamide over the surface of the composite. Further studies confirmed the supramolecular functionalization assembly of isonicotinamide onto the surface of GO. The prepared nanocomposite was used as functional electrode material to fabricate room-temperature NO2 gas sensor. The fabricated electrode (Iso-rGO/CF) exhibited excellent reductive behavior of NO2 gas at room-temperature. The fabricated sensor exhibited a linear range from 1–30 ppm and a low detection limit (LOD) of 1 ppm towards NO2 gas. The NO2 sensitivity of the Iso-rGO/CF electrode is well correlated with online gas chromatography which demonstrate high sensitivity and good stability for more than 30 days. The observed results revealed that the proposed Iso-rGO/CF electrode could be a suitable sensor electrode for the sensitive detection of gaseous NO2 in the real samples.

Developing stable and highly efficient bifunctional electrocatalyst is very important for sustainable energy conversion technology. However, conventional electrocatalytic materials often show high overpotentials and low chemical activities. Conductive polymers anchored is thought an effective strategy to solve this problem. In this work, we report a kind of novel nanosheet arrays through a facile hydrothermal and subsequent electrodeposition process. The as-obtained CoNi2S4@PEDOT-150 products possess an overpotential of 270 mV for oxygen evolution reaction (OER) at 50 mA cm−2 and 90 mV for hydrogen evolution reaction (HER) at 10 mA cm−2 in 1.0 M KOH electrolyte. In addition, the electrode can be used as both anode and cathode for overall water splitting. It only requires a cell voltage of 1.75 V at 50 mA cm−2, which is superior to previous reports.