Explore the vast range of titles available.

Waveguides with sub-100 nm thickness offer a promising platform for sensors. We designed and analyzed multimode interference (MMI) devices using these ultrathin platforms for use as biosensors. To verify our design methodology, we compared the measured and simulated spectra of fabricated 220-nm-thick MMI devices. Designs of the MMI biosensors based on the sub-100 nm platforms have been optimized using finite difference time domain simulations. At a length of 4 mm, the 50-nm-thick MMI sensor provides a sensitivity of roughly 420 nm/RIU and with a figure of merit (FOM) definition of sensitivity/full-width-at-half-maximum, the FOM is 133. On the other hand, using a thickness of 70 nm results in a more compact design—only 2.4 mm length was required to achieve a similar FOM, 134, with a sensitivity of 330 nm/RIU. The limits of detection (LOD) were calculated to be 7.1 × 10−6 RIU and 8.6 × 10−6 RIU for the 50 nm and the 70-nm-thick sensor, respectively. The LOD for glucose sensing was calculated to be less than 10 mg dL−1 making it useful for detecting glucose in the diabetic range. The biosensor is also predicted to be able to detect layers of protein, such as biotin-streptavidin as thin as 1 nm. The ultrathin SOI waveguide platform is promising in biosensing applications using this simple MMI structure.

We demonstrate, for the first time, the synthesis of highly ordered titanium oxynitride nanotube arrays sensitized with Ag nanoparticles (Ag/TiON) as an attractive class of materials for visible-light-driven water splitting. The nanostructure topology of TiO 2 , TiON and Ag/TiON was investigated using FESEM and TEM. The X-ray photoelectron spectroscopy (XPS) and the energy dispersive X-ray spectroscopy (EDS) analyses confirm the formation of the oxynitride structure. Upon their use to split water photoelectrochemically under AM 1.5 G illumination (100 mW/cm 2 , 0.1 M KOH), the titanium oxynitride nanotube array films showed significant increase in the photocurrent (6 mA/cm 2 ) compared to the TiO 2 nanotubes counterpart (0.15 mA/cm 2 ). Moreover, decorating the TiON nanotubes with Ag nanoparticles (13 ± 2 nm in size) resulted in exceptionally high photocurrent reaching 14 mA/cm 2 at 1.0 V SCE . This enhancement in the photocurrent is related to the synergistic effects of Ag decoration, nitrogen doping, and the unique structural properties of the fabricated nanotube arrays.

Significant improvement of the catalytic activity of palladium-based catalysts toward carbon monoxide (CO) oxidation reaction has been achieved through alloying and using different support materials. This work demonstrates the promoting effects of the nanointerface and the morphological features of the support on the CO oxidation reaction using a Pd-Cu/TiO2 catalyst. Pd-Cu catalysts supported on TiO2 were synthesized with wet chemical approaches and their catalytic activities for CO oxidation reaction were evaluated. The physicochemical properties of the prepared catalysts were studied using standard characterization tools including SEM, EDX, XRD, XPS, and Raman. The effects of the nanointerface between Pd and Cu and the morphology of the TiO2 support were investigated using three different-shaped TiO2 nanoparticles, namely spheres, nanotubes, and nanowires. The Pd catalysts that are modified through nanointerfacing with Cu and supported on TiO2 nanowires demonstrated the highest CO oxidation rates, reaching 100% CO conversion at temperature regime down to near-ambient temperatures of ~45 °C, compared to 70 °C and 150 °C in the case of pure Pd and pure Cu counterpart catalysts on the same support, respectively. The optimized Pd-Cu/TiO2 nanowires nanostructured system could serve as efficient and durable catalyst for CO oxidation at near-ambient temperature.

Assigned to their outstanding physicochemical properties, TiO2-based materials have been studied in various applications. Herein, TiO2 doped with different Mo contents (Mo-TiO2) was synthesized via a microwave-assisted solvothermal approach. This was achieved using titanium (IV) butoxide and molybdenum (III) chloride as a precursor and dodecylamine as a surface directing agent. The uniform effective heating delivered by microwave heating reduced the reaction time to less than 30 min, representing several orders of magnitude lower than conventional heating methods. The average particle size ranged between 9.7 and 27.5 nm and it decreased with increasing the Mo content. Furthermore, Mo-TiO2 revealed mesoporous architectures with a high surface area ranging between 170 and 260 m2 g−1, which is superior compared to previously reported Mo-doped TiO2. The performance of Mo-TiO2 was evaluated towards the adsorption of Rhodamine B (RhB). In contrast to TiO2, which revealed negligible adsorption for RhB, Mo-doped samples depicted rapid adsorption for RhB, with a rate that increased with the increase in Mo content. Additionally, Mo-TiO2 expressed enhanced adsorption kinetics for RhB compared to state-of-the-art adsorbents. The introduced synthesis procedure holds a grand promise for the versatile synthesis of metal-doped TiO2 nanostructures with outstanding physicochemical properties.

In this study, xCuO-CeO2 mixed oxide catalysts (Cu weight ratio x = 1.5, 3, 4.5, 6 and 15 wt.%) were prepared using solution combustion synthesis (SCS) and their catalytic activities towards the methane (CH4) oxidation reaction were studied. The combustion synthesis of the pure CeO2 and the CuO-CeO2 solid solution catalysts was performed using copper and/or cerium nitrate salt as an oxidizer and citric acid as a fuel. A variety of standard techniques, including scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), thermo-gravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy were employed to reveal the microstructural, crystal, thermal and electronic properties that may affect the performance of CH4 oxidation. The CuO subphase was detected in the prepared solid solution and confirmed with XRD and Raman spectroscopy, as indicated by the XRD peaks at diffraction angles of 35.3° and 38.5° and the Ag Raman mode at 289 cm−1, which are characteristics of tenorite CuO. A profound influence of Cu content was evident, not only affecting the structural and electronic properties of the catalysts, but also the performance of catalysts in the CH4 oxidation. The presence of Cu in the CeO2 lattice obviously promoted its catalytic activity for CH4 catalytic oxidation. Among the prepared catalysts, the 6% CuO-CeO2 catalyst demonstrated the highest performance, with T50 = 502 °C and T80 = 556 °C, an activity that is associated with the availability of a fine porous structure and the enhanced surface area of this catalyst. The results demonstrate that nanocrystalline copper-ceria mixed oxide catalysts could serve as an inexpensive and active material for CH4 combustion.

Lithium-rich layered oxides (LLOs) such as Li 1.2 Ni 0.13 Mn 0.54 Co 0.13 O 2 are suitable cathode materials for future lithium-ion batteries (LIBs). Despite some salient advantages, like low cost, ease of fabrication, high capacity, and higher operating voltage, these materials suffer from low cyclic stability and poor capacity retention. Several different techniques have been proposed to address the limitations associated with LLOs. Herein, we report the surface modification of Li 1.2 Ni 0.13 Mn 0.54 Co 0.13 O 2 by utilizing cheap and readily available silica (SiO 2 ) to improve its electrochemical performance. Towards this direction, Li 1.2 Ni 0.13 Mn 0.54 Co 0.13 O 2 was synthesized utilizing a sol–gel process and coated with SiO 2 (SiO 2  = 1.0 wt%, 1.5 wt%, and 2.0 wt%) employing dry ball milling technique. XRD, SEM, TEM, elemental mapping and XPS characterization techniques confirm the formation of phase pure materials and presence of SiO 2 coating layer on the surface of Li 1.2 Ni 0.13 Mn 0.54 Co 0.13 O 2 particles. The electrochemical measurements indicate that the SiO 2 -coated Li 1.2 Ni 0.13 Mn 0.54 Co 0.13 O 2 materials show improved electrochemical performance in terms of capacity retention and cyclability when compared to the uncoated material. This improvement in electrochemical performance can be related to the prevention of electrolyte decomposition when in direct contact with the surface of charged Li 1.2 Ni 0.13 Mn 0.54 Co 0.13 O 2 cathode material. The SiO 2 coating thus prevents the unwanted side reactions between cathode material and the electrolyte. 1.0 wt% SiO 2 -coated Li 1.2 Ni 0.13 Mn 0.54 Co 0.13 O 2 shows the best electrochemical performance in terms of rate capability and capacity retention.

Significant improvement of the catalytic activity of palladium-based catalysts toward carbon monoxide (CO) oxidation reaction has been achieved through alloying and using different support materials. This work demonstrates the promoting effects of the nanointerface and the morphological features of the support on the CO oxidation reaction using a Pd-Cu/TiO catalyst. Pd-Cu catalysts supported on TiO were synthesized with wet chemical approaches and their catalytic activities for CO oxidation reaction were evaluated. The physicochemical properties of the prepared catalysts were studied using standard characterization tools including SEM, EDX, XRD, XPS, and Raman. The effects of the nanointerface between Pd and Cu and the morphology of the TiO support were investigated using three different-shaped TiO nanoparticles, namely spheres, nanotubes, and nanowires. The Pd catalysts that are modified through nanointerfacing with Cu and supported on TiO nanowires demonstrated the highest CO oxidation rates, reaching 100% CO conversion at temperature regime down to near-ambient temperatures of ~45 °C, compared to 70 °C and 150 °C in the case of pure Pd and pure Cu counterpart catalysts on the same support, respectively. The optimized Pd-Cu/TiO nanowires nanostructured system could serve as efficient and durable catalyst for CO oxidation at near-ambient temperature.

The kinetics of oxidation of N , N ′-ethylenebis(isonitrosoacetyleacetoneimine)copper(II) complex, Cu II L, by N -bromosuccinimide (SBr) in weakly aqueous acidic solutions was studied under pseudo-first-order conditions. Plots of ln( A ∞  −  A t ) versus time where A t and A ∞ are absorbance values of the Cu(III) product at time t and infinity, respectively, showed marked deviations from linearity. The curves showed an acceleration of reaction rate consistent with an autocatalytic behavior. In the presence of Hg(II) ions, plots of ln( A ∞  −  A t ) versus time are linear up to >85 % of reaction. The value of the observed rate constant, k obs , increases with decreasing pH. At constant reaction conditions, the dependence of the observed rate constants, k obs , is described by Eq. ( 1 ). 1 The dependence of both k o and k 1 on [SBr] is not linear. The mechanism of the title reaction is consistent with an inner sphere mechanism in which a pre-equilibrium step precedes the electron transfer step. The overall rate law is represented by Eq. ( 2 ) where [Cu II L] t and K 1 represent the total copper(II) complex concentration and the pre-equilibrium formation constant, respectively. 2 .

(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image) The kinetics of oxidation of N,Nâ[euro]²-ethylenebis(isonitrosoacetyleacetoneimine)copper(II) complex, Cu^sup II^L, by N-bromosuccinimide (SBr) in weakly aqueous acidic solutions was studied under pseudo-first-order conditions. Plots of ln(A ^sub â z^Â â 'Â A ^sub t^) versus time where A ^sub t^ and A ^sub â z^ are absorbance values of the Cu(III) product at time t and infinity, respectively, showed marked deviations from linearity. The curves showed an acceleration of reaction rate consistent with an autocatalytic behavior. In the presence of Hg(II) ions, plots of ln(A ^sub â z^Â â 'Â A ^sub t^) versus time are linear up to >85Â % of reaction. The value of the observed rate constant, k ^sub obs^, increases with decreasing pH. At constant reaction conditions, the dependence of the observed rate constants, k ^sub obs^, is described by Eq. (1)...The dependence of both k ^sub o^ and k ^sub 1^ on [SBr] is not linear. The mechanism of the title reaction is consistent with an inner sphere mechanism in which a pre-equilibrium step precedes the electron transfer step. The overall rate law is represented by Eq. (2) where [Cu^sup II^L]^sub t^ and K ^sub 1^ represent the total copper(II) complex concentration and the pre-equilibrium formation constant, respectively...[PUBLICATION ABSTRACT]

Algal blooms resulting from eutrophication pose a significant global challenge, contributing to the degradation of freshwater ecosystems. In this study, algal biomass from eutrophic water bodies was utilized for bioenergy production, offering a dual benefit of addressing energy demands while contributing to water body restoration. Alum, a widely used coagulant (40 mg/L), was employed to harvest algal biomass from eutrophic water. Anaerobic digestion (AD) was used to convert the harvested biomass into bioenergy, with the process efficiency strongly dependent on substrate hydrolysis. To enhance hydrolysis, a combined pretreatment involving sonication and alkyl polyglucoside was investigated. Under optimal sonication conditions (160 W for 30 min), chemical oxygen demand (COD) solubilization reached 21.2%. The addition of alkyl polyglucoside (10 µL) during sonication increased COD solubilization to 30.9%. Biomethane yield following the combined pretreatment reached 240.1 mL/gVS, which is significantly higher than that obtained with sonication alone (189.5 mL/g VS). Energy analysis indicated an energy ratio of 0.976 and a net energy of −2.4 kWh for the combined pretreatment. Despite improved solubilization and biomethane yield, the current energy ratio does not support the viability of scaling up the process. This work presents the effect of combined surfactant and ultrasonic pretreatment on increasing the hydrolytic potential of mixed microalgae harvested from eutrophic water for bioenergy generation. Pretreatment enhances the solubilization and biomethane production; however, it still faces challenges in full‐scale application.