Search NASA⌕ Search

SEARCH · Search NASA

Results for “UV spectroscopy”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Low duty cycle pulsed UV technique for spectroscopy of aluminum monochloride

We present what we believe to be a novel technique to minimize UV-induced damage in experiments that employ second-harmonic generation cavities. The principle of our approach is to reduce the duty cycle of the UV light as much as possible to prolong the lifetime of the used optics. The low duty cycle is achieved by ramping the cavity into resonance for a short time during the experimental cycle when the light is used and tuning it to an off-resonant state otherwise. The necessary fast ramp and length-stabilization control of the cavity is implemented with the FPGA-based STEMlab platform. We demonstrate the utility of this method by measuring the isotope shift of the electronic transition (X 1 Σ ← A 1 Π) in AlCl at 261.5 nm in a pulsed molecular beam experiment.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Spectroscopic features of dissolved iodine in pristine and gamma-irradiated nitric acid solutions

While iodine speciation is important for a wide range of nuclear activities, understanding the mechanisms of the transformations of iodine between chemical forms and the sensitivity of these transitions to solution conditions and exposure to radiation remains an active area of research. This work curates spectroscopic data from several experimental techniques and establishes their sensitivity and limitations in detecting changes in iodine speciation in both neutral and acidic regimes. The techniques include Raman spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, 127 I NMR spectroscopy, and ultraviolet-visible (UV-Vis) spectroscopy. Analysis of these data indicates that these commonly accessible spectroscopies often have dynamic ranges of measurable concentrations that do not always overlap between all techniques. The experimental techniques are disparately sensitive to iodide (I - ), molecular iodine (I 2 ), iodate (IO 3 - ), and periodate (IO 4 - ) species. Raman, FTIR, and NMR spectra were subsequentially analyzed using two-dimensional correlation analyses to generate high-resolution autocorrelation spectra. Here, the use of these spectroscopies is then extended to tracking acidification-induced and gamma irradiation-induced transformations of dissolved sodium iodate in deionized water and concentrated nitric acid. Both dissolution into nitric acid and irradiation with a gamma source are demonstrated to perturb the iodine speciation promoting their assembly into molecular iodine (I 2 ) and/or triiodide (I 3 - ). While I 2 and I 3 - species are undetectable with FTIR spectroscopy and 127 I NMR spectroscopy, the species can be detected with UV-Vis spectroscopy, and in some instances, I 3 - can be detected with Raman spectroscopy in the low wavenumber region. Ultimately, the results of this work provide a path to designing optimal combinations of techniques to detect forms of iodine across a wide range of concentrations and conditions.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2022

Identifying hydroxylated copper dimers in SSZ-13 via UV-vis-NIR spectroscopy

Cu-Exchanged zeolites are promising materials for the selective conversion of methane to methanol. Their activity is attributed to the presence of small Cu-oxo and Cu-hydroxy clusters, but the nature of active centers in various zeolite structures is still under debate. In this contribution, we combine time dependent density functional theory with spin–orbit coupling to predict the optical spectra of various Cu monomers and dimers in SSZ-13. As a result, we furthermore compare theoretical results to experimental measurements and find that the presence of Cu-hydroxy dimers and Cu monomers could potentially explain the experimentally observed UV-vis-NIR spectra.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Reversible Crosslinked Polymer Binder for Recyclable Lithium Sulfur Batteries with High Performance

Owing to the negative impact of the extensive utilization of batteries on the environment, sustainability of the cells needs to be included in the systemic research of batteries. In this work, a dissolvable ionic crosslinked polymer (DICP) is exploited as a binder for lithium–sulfur batteries by crosslinking the polyacrylic acid and polyethyleneimine through carboxy-amino ionic interaction. This interaction is pH-controlled, and therefore, the crosslinked binder network can be readily dissociated under basic conditions, providing a facile strategy enabling valuable components recycled through a convenient washing method. The sulfur cathode prepared using the recycled carbon–sulfur composite can deliver comparable capacity as that of fresh electrode. In addition, evidence from cell performance and characterizations, such as in situ X-ray absorption spectroscopy, in situ UV–visible spectroscopy, X-ray photoelectron spectroscopy, and density functional theory calculation, confirms that DICP is a more effective binder than its commercial counterpart on suppressing polysulfide dissolution in the electrolyte. Exploiting reversible crosslinked polymer binder for recyclable Li–S batteries with ameliorated electrochemical performance, this study illuminates sustainable development for large-scale energy storage systems.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Adsorption of molecular iodine and alkyl iodides from spent-nuclear-fuel-reprocessing off-gas using reduced silver mordenite

Radioactive iodine is a hazardous byproduct of spent-nuclear-fuel reprocessing that must be removed from the off-gas stream before it can be discharged. Reduced silver mordenite (Ag 0 Z) is currently the baseline material for iodine capture in the U.S. Although the performance characteristics and capture mechanisms of I 2 and CH 3 I have been established, similar investigations into long-chain organic iodides have yet to be performed. In this study, thin beds of Ag 0 Z were loaded with I 2 , CH 3 I, C 4 H 9 I, and C 12 H 25 I (5 ppm to 50 ppm) carried in a dry air stream at 150°C. The maximum iodine capacity was 105 ± 5 mg I/g Ag 0 Z for all species. Saturated Ag 0 Z samples were characterized using scanning electron microscopy, X-ray fluorescence, X-ray photoelectron spectroscopy, diffuse reflectance UV–visible spectroscopy, pair distribution function analysis, and thermogravimetric analysis. Further, near-complete Ag utilization and similar physical/chemical properties were observed for all samples. Through a comparison with previous studies and an investigation of aged Ag 0 Z, we propose that iodine species react with Ag + at exchange sites, forming α-AgI within the mordenite channels, and with surface Ag 0 nanoparticles, yielding β-/γ-AgI. The available Ag sites in the interior (Ag + ) and exterior (Ag 0 ) of mordenite determine the adsorption capacity since α-AgI formation is limited by the total pore volume. Potential iodine uptake routes were summarized for aging and non-aging environments. A scalable predictive model was implemented for deep-bed iodine removal, and predictions were in good agreement with experimental data. Sensitivity analysis suggests that iodine uptake kinetics is governed by pore diffusion.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2024

Single-Atom Manganese-Based Catalysts for the Oxidative Dehydrogenation of Propane

Combinatorial screening of 150 supported metal oxide (manganese and additives) catalysts was carried out via a high-throughput synthesis platform and parallel reactors for the oxidative dehydrogenation (ODH) of propane to propylene. Specifically, an organomanganese (0.05-2.5 Mn atoms/nm 2 ) complex was grafted on metal oxide supports (Al 2 O 3 , SiO 2 , TiO 2 , and ZrO 2 ) premodified with either Lewis acid (Al, Ti, Zn, and Zr) or redox-active (Cu, Cr, Ga Ni, V) additives at various surface coverages (25, 50, and 75%). Catalysts were characterized by high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Raman spectroscopy, and UV-vis spectroscopy. Catalysts 0.05 Mn/V(50%)/Al 2 O 3 and 0.05 Mn/Ni(50%)/ZrO 2 showed the highest combined propane conversion and propylene selectivities (31/41% and 15/85%), with excellent stability at 500 degrees C for 25 h. The presence of Ni in Mn/Ni/ZrO 2 resulted in a 6-fold increase in turnover frequency (TOF) over the Mn/ZrO 2 . HRTEM identified single Mn atoms after 500 degrees C heat treatment. For the Mn/Ni/ZrO 2 system, Mn was incorporated into the support lattice due to the similar ionic radius of Mn 2+ and Zr 4+ , which was also enhanced by the presence of Ni. For the Mn/V/Al 2 O 3 system, highly active MnO was prevalent as observed by Raman. Both V and Mn contributed to an increase in mutual dispersion, but both species remained on the surface. Finally, it is proposed that the highly dispersed atom and interactions between Mn with either Ni or V are responsible for the ODH performance and stability.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Cascade Reaction of Ethanol to Butadiene over Multifunctional Silica-Supported Ag and ZrO 2 Catalysts

Although butadiene is currently a by-product of naphtha cracking, interest in producing butadiene from bio-based ethanol has increased because of the lower environmental impact of the ethanol to butadiene reaction. Furthermore, this work explores a multifunctional catalyst system composed of silica-supported Ag and ZrO 2 used for the cascade reaction of ethanol to butadiene at 573 K. The Ag and ZrO 2 components were synthesized on separate support particles enabling characterization of each component without interference from the other. High selectivity to butadiene (65%) at high ethanol conversion (75%) was achieved with an appropriate ratio of Ag and ZrO 2 in the reactor. Silver catalyzed the initial dehydrogenation of ethanol to acetaldehyde while ZrO 2 catalyzed the C-C coupling and subsequent dehydration reactions. The silica-supported ZrO 2 exhibited superior selectivity relative to bulk ZrO 2 in the Ag-promoted ethanol to butadiene reaction. Results from Zr K-edge X-ray absorption spectroscopy and UV-Vis spectroscopy showed that ZrO 2 was highly dispersed on the silica support over a range of loadings. Infrared spectroscopy of adsorbed pyridine, CO, and CO 2 , and kinetics of probe reactions 1-butene double bond isomerization, 2-propanol decomposition, and ethanol hydrogenation of acetone were used to compare the acid-base nature and chemical reactivity of silica-supported ZrO 2 to bulk ZrO 2 .

09 BIOMASS FUELS↗
DOE OSTI2021

AlGaN/GaN metal–insulator–semiconductor high electron mobility transistors (MISHEMTs) using plasma deposited BN as gate dielectric

AlGaN/GaN metal–insulator–semiconductor high electron mobility transistors (MISHEMTs) were fabricated on Si substrates with a 10 nm boron nitride (BN) layer as a gate dielectric deposited by electron cyclotron resonance microwave plasma chemical vapor deposition. The material characterization of the BN/GaN interface was investigated by X-ray photoelectric spectroscopy (XPS) and UV photoelectron spectroscopy. The BN bandgap from the B1s XPS energy loss is ~5 eV consistent with sp2 bonding. The MISHEMTs exhibit a low off-state current of 1 × 10 –8 mA/mm, a high on/off current ratio of 10 9 , a threshold voltage of –2.76 V, a maximum transconductance of 32 mS/mm at a gate voltage of –2.1 V and a drain voltage of 1 V, a subthreshold swing of 69.1 mV/dec, and an on-resistance of 12.75 Ω·mm. The interface state density (D it ) is estimated to be less than 8.49 × 10 11 cm –2 eV –1 . Gate leakage current mechanisms were investigated by temperature-dependent current–voltage measurements from 300 K to 500 K. The maximum breakdown electric field is no less than 8.4 MV/cm. Poole–Frenkel emission and Fowler–Nordheim tunneling are indicated as the dominant mechanisms of the gate leakage through the BN gate dielectric at low and high electric fields, respectively.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Structural and electronic properties of rare-earth chromites: A computational and experimental study

Here, in this work, the structural, optical, and electronic properties of rare-earth perovskites of the general formula R⁢ CrO 3 , where R⁢ represents the rare-earth Gd, Tb, Dy, Ho, Er, and Tm, have been studied in detail. These compounds were synthesized through a facile citrate route. X-ray diffraction, Raman spectroscopy, and UV-Visible spectroscopy were utilized to reveal the structural evolutions in R⁢ ⁢CrO 3 . The lattice parameters, Cr 3+ –O 2 –Cr 3+ bond angle, and CrO 6 octahedral distortions were found to strongly depend on the ionic radii of R⁢ . First-principles calculations based on density-functional theory within the generalized gradient approximation (GGA) of Perdew-Burke-Ernzerhof (PBE) and strongly constrained and appropriately normed (SCAN) meta-GGA were also employed to calculate the structural and electronic properties of R⁢ ⁢CrO 3 . The ground-state energy, lattice constants, electronic structures, and density of states of R⁢ ⁢CrO 3 were calculated. These provide some insights into the electronic characteristics of the R⁢ ⁢CrO 3 compounds. The calculated values of lattice parameters and band gaps with Hubbard U correction (SCAN+ U ) agree well with values measured experimentally and show more accuracy in predicting the ground-state crystal structure and band structure compared to PBE+ U approximation. The band gap of R⁢ ⁢CrO 3 is found to be independent of the ionic radii of R⁢ from both experiments and calculations.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2020

Excited state dynamics of cis , cis -1,3-cyclooctadiene: UV pump VUV probe time-resolved photoelectron spectroscopy

We present UV pump, vacuum ultraviolet probe time-resolved photoelectron spectroscopy measurements of the excited state dynamics of cis,cis-1,3-cyclooctadiene. A 4.75 eV deep UV pump pulse launches a vibrational wave packet on the first electronically excited state, and the ensuing dynamics are probed via ionization using a 7.92 eV probe pulse. The experimental results indicate that the wave packet undergoes rapid internal conversion to the ground state in under 100 fs. Comparing the measurements with electronic structure and trajectory surface hopping calculations, we are able to interpret the features in the measured photoelectron spectra in terms of ionization to several states of the molecular cation.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Synthesis and Characterization of Pd-based Nanomaterials

Bimetallic nanoparticles (BNPs) consist of two different types of metals or alloys that are bonded together. Unique properties such as optical, electronic, thermal, and catalytic effects differ for each type of BNP. Important BNPs range from Au-Pd, Ag- Pt, Au-Pt, and Ag-Ni. Pd bimetallic nanoparticles are of interest due to their many applications such as catalysis and sensing. Bimetallic catalysts have increase reaction rates and have improved catalyst stability through the geometry and ligand distribution. Pd nanoparticles are considered to be a strong catalyst due to their high activity at low temperatures and high tolerance to moisture. The catalytic properties of bimetallic nanoparticles depend on the structural properties such as size and shape. Core-shell, hollow structure, and multi-shell alloy are three possible structures nanoparticles can form as bimetallic catalysts. BNPs can be synthesized through different methods to control the size, shape, and structure. To obtain different morphologies, a variety of methods can be performed. Different methods can range from the usage of the glancing angle deposition (GLAD) to the galvanic replacement reaction, but the methods all depend on the properties of the metals. The galvanic displacement reaction was the method used to obtain Pd-based nanoparticles. This reaction is best know for obtaining hollow shaped NPs. To determine what redox process was preformed, the activity series of metals was used. From the activity series of metals, silver (Ag) was selected to preform Pd-based nanoparticles. Objectives: Synthesize Ag nanoparticles and Ag-Pd nanoparticles to understand the morphology. Characterize the synthesized nanoparticles using scanning electron microscopy (SEM), phase analysis light scattering (PALS), dynamic light scattering (DLS), energy dispersive X-ray spectroscopy (EDS), and UV-Vis spectroscopy. Results: In the UV-Vis spectrum, the Ag-Pd bimetallic NP's plasmon band decreased as the volume of palladium increased. The surface charge increases as the concentration of palladium increases. The Pd{sup 2+} ions interact with the sodium citrate surface, and decrease the negative charge. Conclusion: Ag-Pd nanoparticles were successfully created and stabilized with sodium citrate. The addition of Pd decreased the prominent plasmon band of the Ag nanoparticles. The SEM analysis showed that Ag nanoparticles had a well-defined structure, while the Ag-Pd nanoparticles showed hollow and rough structure. The EDX analysis confirmed the presence of silver and palladium. This material can be used in many industrial and research fields such as organic synthesis, fuel cells, and environmental sensing and remediation.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2026

UV–Vis–NIR Reflectance Spectroscopy and Chemometrics for Monitoring Pu Directly on an Ion Exchange Column

Here, we present a fiber-optic UV–vis–NIR reflectance spectroscopy method for direct, noninvasive monitoring of Pu(IV) in a glass ion exchange column during dynamic loading and elution in a glovebox. A movable probe enables spatially resolved spectral acquisition along the column axis, capturing distinct features associated with Pu(IV) nitrate complexes during loading and free ions during elution. Principal component analysis was applied to extract the dominant spectral variance and resolve relative concentration profiles without requiring precise knowledge of optical penetration depth or species identity. This in situ approach reveals spatial gradients and speciation dynamics in real time, which provides actionable insight into Pu(IV) ion migration, resin saturation, and breakthrough behavior under evolving flow conditions. The method offers a practical, fiber-compatible strategy to monitor glass column–based separations for Pu and other lanthanides or actinides and to characterize metal–resin interactions in flow-through systems.

actinide↗
DOE OSTI2021

Two-Dimensional and Three-Dimensional Tetrel-Arsenide Frameworks Templated by Li and Cs Cations

Two new ternary tetrel pnictide phases, Li 1.08 Ge 4.92 As 7 and Cs 0.11 Zn 0.05 Si 0.95 As, have been synthesized. Both compounds crystallize in new structure types, which demonstrate the flexibility of Ge(Si)–As layers when accommodating electropositive cations of various sizes. Li 1.08 Ge 4.92 As 7 displays a Ge-As layer motif that has not been observed in ternary Ge-As systems, while Cs 0.11 Zn 0.05 Si 0.95 As exhibits a 3D framework composed of fragments of the 2D parent-phase SiAs. For Li 1.08 Ge 4.92 As 7 , a combination of computational modeling and solid-state 7 Li MAS NMR was used to establish the correct crystal structure with one mixed occupied Ge/Li site. The compositions of the phases were confirmed through energy-dispersive X-ray spectroscopy. Transport properties and UV–Vis spectroscopy reveal both reported compounds to be semiconductors. Cs 0.11 Zn 0.05 Si 0.95 As shows high thermal stability with congruent melting at 1300 K and an exceptionally low thermal conductivity of 0.5 W m –1 K –1 at 300 K. Temperature-dependent Li-ion hopping dynamics in Li 1.08 Ge 4.92 As 7 was characterized using 7 Li solid-state NMR.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Alkali Counterion-Dependent Crystallization of Uranium(IV)–Chloro Structural Units

The synthesis, structural characterization, and spectroscopic properties of five tetravalent uranium (U) phases including Li 6 [U 4 (μ 3 -O) 2 Cl 18 (H 2 O) 2 ]·10H 2 O (1), [U(H 2 O) 4 Cl 4 ] (2), [U(H 2 O) 4 Cl 4 ]·KCl (3), Rb 2 UCl 6 (4), and Cs 2 UCl 6 (5) are reported. Notably, a change in the U 4+ solid-state structural unit was observed based on the identity of the alkali counterion used in the synthesis. Li 1+ yielded a tetranuclear oxo-bridged cluster, [U 4 (μ 3 -O) 2 Cl 18 (H 2 O) 2 ] 6– , Na 1+ and K 1+ yielded two structurally distinct [U(H 2 O) 4 Cl 4 ] complexes, and Rb 1+ and Cs 1+ resulted in [UCl 6 ] 2– as the dominant phases. The spectroscopic properties of the compounds were analyzed using Raman and UV–vis–NIR absorption spectroscopy. The UV–vis–NIR spectra of compounds 1–5 exhibited transitions consistent with uranium in the +4 oxidation state. Clear differences in the absorption band splitting were observed and are likely attributed to differences in metal ion coordination, crystal field effects, and outer sphere interactions Overall, this work demonstrates the utility of noncovalent interactions in tuning the crystallization of various metal complexes from otherwise identical reaction solutions and provides further evidence that counterions impact the composition and structure of actinide complexes isolated in the solid state. In this way, this work affords important insight into directing and controlling the structure of actinide complexes and clusters.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Models to Incorporate Reaction Mechanisms into DG-OSPREY: Fixed-Bed Simulations for Organic Iodides Capture Using Ag 0 Z

As one of the most potent radioisotopes released during spent nuclear fuel reprocessing, 129 I is strictly regulated and must be removed before discharge. Organic iodides (primarily alkyl iodides with different chain lengths, i.e., CH 3 I, C 4 H 9 I, and C 12 H 25 I) comprise ~2% of the total iodine in the reprocessing off-gases and are primarily present in vessel off-gas (VOG). Reduced silver mordenite (Ag 0 Z) is predominantly considered for the removal of radioiodine; however, its capture performance and underlying interaction processes with long-chain organic iodides are not fully understood. Two major tasks were accomplished in this study. First, to improve upon the previous experimental studies where Ag 0 Z was used to capture CH 3 I, C 4 H 9 I, and C 12 H 25 I at different concentrations, we comprehensively investigated the corresponding capture mechanisms by characterizing fully loaded Ag 0 Z samples. Second, computational codes were implemented to perform fixed-bed simulations that account for transport and reaction mechanisms. Scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDX), powder X-ray diffraction (PXRD), UV-visible diffuse reflectance spectroscopy (UV-vis DRS), and thermogravimetric analysis (TGA) were conducted on Ag 0 Z samples that are saturated with I 2 , CH 3 I, C 4 H 9 I, and C 12 H 25 I), respectively. Results indicate that AgI is the predominant adsorption product regardless of the adsorbed iodine species, yet alkyl iodides with different carbon chain lengths may have different compositions of α- and γ-AgI. Synchrotron pair distribution function (PDF) measurements and TGA coupled with a Fourier transformed infrared detector (TGA FTIR) have been performed, and experimental data are currently analyzed. Results are expected to provide further insights into the adsorption mechanisms. The fixed-bed capture performance for CH 3 I was successfully simulated by solving mathematical equations that describe the underlying transport processes and adsorption reactions. The computational framework, Catalytic After Treatment System (CATS), that was originated in our research group, was used to solve the governing equations. Kinetic parameters, including the pore diffusivity and reaction rate constant were obtained by optimization techniques using data from thin-bed experiments performed at Oak Ridge National Laboratory. The performance of a deep bed predicted using the optimized parameters showed promising agreement with the experimental data.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2024

Ultrafast photoinduced charge carrier dynamics of L-cysteine and oleylamine stabilized CsPbBr3 perovskite quantum dots coupled with gold nanoparticles

We have synthesized L-cysteine and oleylamine stabilized CsPbBr3 perovskite quantum dots (PQDs) and coupled them with gold nanoparticles (AuNPs). The PQDs and AuNPs, as well as their hybrid nanostructures (HNS), were characterized using UV–visible (UV–vis) and photoluminescence (PL) spectroscopy. The UV–vis spectra show absorption bands of the HNS at 503 and 520 nm, attributed mainly to PQDs and AuNPs, respectively. The PQDs show a strong excitonic PL band peaked at 513 nm from PQDs. The HR-TEM results show the formation of hybrid structures between PQDs and AuNPs, which is also supported by the PL quenching of the PQDs by the coupled AuNPs. Ultrafast dynamics of the exciton and charge carriers in the HNS and pristine PQD were studied using femtosecond transient absorption. Multiexponential fitting of the dynamic data revealed the existence of shallow and deep trap states in pristine PQDs and ultrafast electron transfer from PQDs to AuNPs in the HNS. A kinetic model was proposed to account for the key dynamic processes involved and to extract the time for electron transfer from PQDs to AuNPs in the HNS, found to be ∼2 ps. Dynamic processes in pristine PQDs are largely unchanged by HNS formation with AuNPs.

Chemistry↗
DOE OSTI2020

Boron carbide amorphous solid with tunable band gap

Boron carbide B x C (x = 1/6 – 10) powders were synthesized through a microwave-assisted carbothermic reduction reaction as a potential clean energy material. Their crystallographic structures and optical properties were characterized. X-ray diffraction and electron diffraction indicated that the synthesized B x C powders were amorphous. Electron energy-loss spectroscopy demonstrated that the composition of boron and carbon was in amorphous materials, and their chemical bonding were disclosed from Raman scattering spectroscopy. Here, UV-vis absorption spectroscopy indicated that the bandgap of the bulks varied from 2.30 eV to 3.90 eV, tuned by the boron/carbon element ratio.

36 MATERIALS SCIENCE↗
DOE OSTI2023

ZnO/CuO nanostructures anchored over Ni/Cu tubular films via pulse electrodeposition for photocatalytic and antibacterial applications

In this work, we report the fabrication of Ni and Cu tubular substrates and the synthesis of ZnO/CuO nanocomposite on them through the process of pulse electrodeposition. The systematic variation in CuO incorporation in the ZnO matrix and the processing technique were noticed to affect the structural, optical, photocatalytic, and anti-bacterial properties, which are well in accordance with the Field Emission-Scanning Electron Microscope, X-ray Diffraction, Fourier transform Infrared Spectroscopy and UV-Differential reflectance spectroscopy results. The remediation capabilities of the photocatalytic substrates were assessed through the degradation of methylene blue (MB) dye under solar irradiation. Optimized CuO incorporation within the ZnO nanorods resulted in the degradation of a 20 ppm of MB dye solution within 40 min and a higher concentration of 50 ppm within 95 min. The Ni and Cu electroformed tubes as substrates provided not only a reusable supporting frame but also a large surface-area for the growth of ZnO/CuO nanocomposite. The current study also dealt with the anti-bacterial efficacy of the above-mentioned substrates against E.coli. Hence, the Ni and Cu tubular thin film substrates with nanorods of ZnO/CuO composite were explored for the removal of organic as well as biological contaminants from waste water.

36 MATERIALS SCIENCE↗