Ceramic Ti/TiO2/AuNP Film with 1-D Nanostructures for Selfstanding Supercapacitor Electrodes

Herein we have fabricated AuTiO2 from a one-dimensional (1D) nanocomposite by the simple oxidation method of the Ti sheet for supercapacitor applications. We intended on fabricating a microlayer extended into the sheet body to form a selfstanding electrode. Raman spectra and XRD patterns confirmed the formation of the rutile phase of the TiO2 bulk, and FESEM confirmed the growth of the 1D nanostructure made of Au/TiO2, where the Au nanoparticles reside on the tip of the TiO2 nanorods. The growth of 1D TiO2 by this method is supported by a growth mechanism during the oxidation process. Three electrodes were fabricated based on pure and doped TiO2. These electrodes were used as a selfstanding supercapacitor electrode. The Au-doped TiO2 exhibited a great improvement in the electrochemical performance at low Au concentrations, whereas the excessive Au concentration on the TiO2 surface exhibited a negative effect on the capacitance value. The highest areal capacitance of 72 mFcm−2 at a current density of 5 µAcm−2 was recorded for TiO2 doped with a low Au concentration. The mechanism of the electrochemical reaction was proposed based on Nyquist and Bode plots. The obtained results point out that the effect of Au on the TiO2 surface makes Au/TiO2 ceramic electrodes a promising material as selfstanding energy storage electrodes

Promising Novel Barium Carbonate One-Dimensional Nanostructures and Their Gas Sensing Application: Preparation and Characterization

Recently, barium carbonate-based nanomaterials have been used for sensor and catalysis applications. The sensing performance can be improved with a suitable one-dimensional nanostructure. In this regard, novel nanosized BaCO3 materials were fabricated by a one-pot designed thermal evaporation system. Ten milligrams of Ba as raw material were used to deposit BaCO3 nanostructures at a pressure of 0.85 torr and a temperature of 850 °C in a partial oxygen atmosphere of the ambient. This simple method for fabricating novel BaCO3 nanostructures is presented here. X-ray diffraction was indexed on the orthorhombic polycrystalline structure of the prepared BaCO3. The nanostructures deposited here could be described as Datura-like structures linked with nanowires of 20–50 nm in diameter and 5 µm in length. The BaCO3 nanostructure prepared by the current method exhibited a semiconductor-like behavior with an activation energy of 0.68 eV. This behavior was ascribed to the nature of the morphology, which may possess large defective points. Thus, this nanostructure was subjected to gas sensing measurements, showing high activity toward NO2 gas. The proposed sensor also underwent deep investigation toward NO2 at various gas concentrations and working. The response and recovery time constants were recorded in the ranges of 6–20 s and 30–150 s, respectively. The sensor showed its reversibility toward NO2 when the sensor signal was repeated at various cycles of various concentrations. The sensor was exposed to different levels of humidity, showing high performance toward NO2 gas at 250 °C. The sensor exhibited fast response and recovery toward NO2 gas

Synergistic Effect of NiO-Ga₂O₂-Graphene Heterostructures on Congo Red Photodegradation in Water

We studied the effect of the mixed phase of nickel oxide–gallium oxide–graphene (NiO-Ga2O2/G) heterostructure nanocomposite on the photocatalytic degradation of Congo red dye. The effect was investigated based on NiO-Ga2O2 junction, NiO-graphene, and Ga2O2-graphene contacts. The laser-induced graphene was embedded into NiO and NiO-Ga2O2. Raman spectra confirmed the fabrication of disordered graphene and the mixed phase between the oxides and graphene. HRTEM showed that very fine nanoparticles for both NiO and Ga2O2 with a size of ~7–10 nm were synthesized. Elemental compositional expressed the formation mixed phase. The effect of graphene content was investigated at 2 and 10% wt with NiO and the heterojunction of NiO-Ga2O2. The photocurrent studies was measured of these nanocomposite film deposited on two interdigitated gold electrodes, biased by 5.0 V and irradiated by the UV source. The results of photocatalysis measurements indicated an improvement occurred upon the heterojunction between Ga2O2 and NiO, however, a dramatic improvement was observed with the addition of graphene of 10%. The results expressed that the ternary phase of p-NiO/n-Ga2O2/graphene is promising in the photocatalytic application toward Congo red decomposition

Photocatalytic Degradation of Phenol Red in Water on Nb(x)/TiO₂ Nanocomposites

In this paper, the photocatalytic effect of Nb(x)/TiO2 nanocomposites on the degradation of phenol red (PR) was studied. Nb(x)/TiO2 nanocomposites are fabricated by a simple sol-gel route with new experimental conditions. The structural and optical properties were determined using high transmission electron microscopy (HRTEM), X-ray diffraction, Raman spectroscopy, photoluminescence, and UV-vis absorbance spectroscopy. Compared to pure anatase TiO2, the recently fabricated Nb(x)/TiO2 nanocomposite has a shift in the optical band edge to the visible wavelength. Consequently, it has high performance in adsorption capacity and photocatalytic activities. A time of 160 min has been observed to be suitable for mostly degradable 20 mgL−1 of phenol red on Nb(2.0)/TiO2 composite. The kinetic results were in good agreement with the first-order kinetic model at different concentrations. In addition, the results showed that the addition of Nb led to a significant degradation process. The decomposition of phenol red pollutants showed a synergistic effect of the Nb(2.0)/TiO2 nanocomposites on wastewater treatment

Gases in Food Production and Monitoring: Recent Advances in Target Chemiresistive Gas Sensors

The rapid development of the human population has created demand for an increase in the production of food in various fields, such as vegetal, animal, aquaculture, and food processing. This causes an increment in the use of technology related to food production. An example of this technology is the use of gases in the many steps of food treatment, preservation, processing, and ripening. Additionally, gases are used across the value chain from production and packaging to storage and transportation in the food and beverage industry. Here, we focus on the long-standing and recent advances in gas-based food production. Although many studies have been conducted to identify chemicals and biological contaminants in foodstuffs, the use of gas sensors in food technology has a vital role. The development of sensors capable of detecting the presence of target gases such as ethylene (C2H4), ammonia (NH3), carbon dioxide (CO2), sulfur dioxide (SO2), and ethanol (C2H5OH) has received significant interest from researchers, as gases are not only used in food production but are also a vital indicator of the quality of food. Therefore, we also discuss the latest practical studies focused on these gases in terms of the sensor response, sensitivity, working temperatures, and limit of detection (LOD) to assess the relationship between the gases emitted from or used in foods and gas sensors. Greater interest has been given to heterostructured sensors working at low temperatures and flexible layers. Future perspectives on the use of sensing technology in food production and monitoring are eventually stated. We believe that this review article gathers valuable knowledge for researchers interested in food sciences and sensing development

Gases in Food Production and Monitoring: Recent Advances in Target Chemiresistive Gas Sensors

The rapid development of the human population has created demand for an increase in the production of food in various fields, such as vegetal, animal, aquaculture, and food processing. This causes an increment in the use of technology related to food production. An example of this technology is the use of gases in the many steps of food treatment, preservation, processing, and ripening. Additionally, gases are used across the value chain from production and packaging to storage and transportation in the food and beverage industry. Here, we focus on the long-standing and recent advances in gas-based food production. Although many studies have been conducted to identify chemicals and biological contaminants in foodstuffs, the use of gas sensors in food technology has a vital role. The development of sensors capable of detecting the presence of target gases such as ethylene (C2H4), ammonia (NH3), carbon dioxide (CO2), sulfur dioxide (SO2), and ethanol (C2H5OH) has received significant interest from researchers, as gases are not only used in food production but are also a vital indicator of the quality of food. Therefore, we also discuss the latest practical studies focused on these gases in terms of the sensor response, sensitivity, working temperatures, and limit of detection (LOD) to assess the relationship between the gases emitted from or used in foods and gas sensors. Greater interest has been given to heterostructured sensors working at low temperatures and flexible layers. Future perspectives on the use of sensing technology in food production and monitoring are eventually stated. We believe that this review article gathers valuable knowledge for researchers interested in food sciences and sensing development

Biosynthesis of CeO2 Nanoparticles Using Egg White and Their Antibacterial and Antibiofilm Properties on Clinical Isolates

Bio-inspired synthesis is a novel and attractive environmentally friendly route to generating inorganic materials. In this work, the preparation of CeO2 NPs using egg white and investigation of their antibacterial properties both in liquid and solid growth medium against Escherichia coli and Staphylococcus aureus bacteria were reported. The CeO2 nanoparticles were characterized using X-ray diffraction (XRD), Field emission transmission electron microscope (FETEM), UV-Vis, Raman, and antibacterial measurements. The results from XRD and TEM analysis showed that the prepared nanoparticles were a single phase in the nano regime (5–7 nm) with spherical shape and uniform size distribution. Optical properties reflected the characteristics peaks of CeO2 in the UV-Vis range with a bandgap ~2.80 eV. The antibacterial activity of the synthesized NPs was achieved under ambient conditions with different bacteria and the results showed that the properties were different for both the bacteria. The highest activity with an inhibition zone of about 22 mm against S. aureus was obtained as compared with the 19 mm zone of inhibition obtained with E.coli. This finding will be of major significance that indicates a possibility to develop CeO2 NPs as antibacterial agents against extensive microorganisms to control and prevent the spread and persistence of bacterial infections

New Approach for Designing Zinc Oxide Nanohybrids to Be Effective Photocatalysts for Water Purification in Sunlight

Water pollution and deficient energy are the main challenges for the scientific society across the world. In this trend, new approaches include designing zinc oxide nanohybrids to be very active in sunlight. In this line, organic and magnetic species intercalate among the nanolayers of Al/Zn to build inorganic-magnetic-organic nanohybrid structures. A series of nanolayered and nanohybrid structures have been prepared through intercalating very fine particles of cobalt iron oxide nanocomposites and long chains of organic fatty acids such as n-capric acid and stearic acid inside the nanolayered structures of Al/Zn. By thermal treatment, zinc oxide nanohybrids have been prepared and used for purifying water from colored pollutants using solar energy. The optical measurements have shown that the nanohybrid structure of zinc oxide leads to a clear reduction of band gap energy from 3.30 eV to 2.60 eV to be effective in sunlight. In this line, a complete removal of the colored pollutants (naphthol green B) was achieved after ten minutes in the presence of zinc oxide nanohybrid and sunlight. Finally, this new approach for designing photoactive nanohybrids leads to positive results for facing the energy- and water-related problems through using renewable and non-polluting energy for purifying water

Growth of Defect-Induced Carbon Nanotubes for Low-Temperature Fruit Monitoring Sensor

Herein, a carbon nanotubes-based sensor has been grown for the purpose of ethylene detection. The prepared CNTs had a crystalline structure with a smooth surface of 11.0 nm in diameter and 10.0 µm in length. The low-intensity graphite peak (G-band) as compared to the peak of the defect (D-band) characterizes the defects in the CNTs. An MWNTs-gas sensor was fabricated for monitoring the ethylene gas. The highest response was recorded at a low operating temperature of 30 °C. The sensor was also examined at 300 ppb up to 10 ppm and it showed a response of 2% up to 28%. The sensor response and recovery time constants were varied from 60 to 300 s, depending on the gas concentration. The results that were obtained for the synthetic ethylene gas were also compared with the real measurements for banana ripening. The results confirmed that the sensor is appropriate for the monitoring of fruit ripening

A Comprehensive Photocatalysis Study of Promising Zirconia/Laser-Induced Graphene Nanocomposite for Wastewater Treatment-Based Methylene Blue Pollution

In this paper, the photocatalytic effect of zirconia/laser-induced graphene on the degradation of methylene blue was comprehensively studied. The average particle size measured by HRTEM is 6 nm for both ZrO2 and ZrO2/G10 samples, which explains the high-quality TEM imaging of isolated squared sections of cubic particles. The weight percentages of Zr, O, and C elements using EDX were 72.16, 18.56, and 9.28, respectively. These results confirm the formation of binary composites. Moreover, Raman scattering exhibited that the spectrum of pure ZrO2 was difficult to be detected due to the high luminescence. However, ZrO2 vibration modes were detected for ZrO2-graphene nanocomposites at 1012, 615, 246, and 150 cm−1. A shift of the D- and G-bands of graphene were observed, where D-peak and G-peak were observed at 1370 and 1575 cm−1 for ZrO2/5G and, 1361 and 1565 cm−1 for ZrO2/10G, respectively. The shift is ascribed to the incorporation of graphene into the surface of the oxide material. Compared to ZrO2, the newly fabricated ZrO2-graphene nanocomposites have the advantage of increased photocatalytic effects. An adsorbent concentration of 5 and 10 mg·L−1 at room temperature over 240 min was observed to be suitable experimental conditions. The kinetic results indicate that the practical results obtained are well expressed by the first-order kinetic model at different concentrations. In addition, the results showed that the addition of graphene led to a significant degradation process increase. The results also showed the significant effect of the investigated ZrO2-graphene nanocomposites on the decomposition of methylene blue cation. The decomposition of cationic pollutants showed a synergistic effect of the ZrO2-graphene nanocomposites on wastewater treatment