Abstract: We describe an optical atomic clock based on quantum-logic spectroscopy of the ^{1}S_{0}↔^{3}P_{0} transition in ^{27}Al^{+} with a systematic uncertainty of 9.4×10^{-19} and a frequency stability of 1.2×10^{-15}/sqrt[τ]. A ^{25}Mg^{+} ion is simultaneously trapped with the ^{27}Al^{+} ion and used for sympathetic cooling and state readout. Improvements in a new trap have led to reduced secular motion heating, compared to previous ^{27}Al^{+} clocks, enabling clock operation with ion secular motion near the three-dimensional ground state. Operating the clock with a lower trap drive frequency has reduced excess micromotion compared to previous ^{27}Al^{+} clocks. Both of these improvements have led to a reduced time-dilation shift uncertainty. Other systematic uncertainties including those due to blackbody radiation and the second-order Zeeman effect have also been reduced.

Abstract: A narrow pentaquark state, P_{c}(4312)^{+}, decaying to J/ψp, is discovered with a statistical significance of 7.3σ in a data sample of Λ_{b}^{0}→J/ψpK^{-} decays, which is an order of magnitude larger than that previously analyzed by the LHCb Collaboration. The P_{c}(4450)^{+} pentaquark structure formerly reported by LHCb is confirmed and observed to consist of two narrow overlapping peaks, P_{c}(4440)^{+} and P_{c}(4457)^{+}, where the statistical significance of this two-peak interpretation is 5.4σ. The proximity of the Σ_{c}^{+}D[over ¯]^{0} and Σ_{c}^{+}D[over ¯]^{*0} thresholds to the observed narrow peaks suggests that they play an important role in the dynamics of these states.

Abstract: Herein, ruthenium (Ru) and iridium (Ir) are introduced to tailor the atomic and electronic structure of self-supported nickel-vanadium (NiV) layered double hydroxide to accelerate water splitting kinetics, and the origin of high hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) activities are analyzed at atomic level. X-ray photoelectron spectroscopy and X-ray absorption near-edge structure spectroscopy studies reveal synergistic electronic interactions among Ni, V, and Ru (Ir) cations. Raman spectra and Fourier and wavelet transform analyses of the extended X-ray absorption fine structure indicate modulated local coordination environments around the Ni and V cations, and the existence of V vacancies. The Debye-Waller factor suggests a severely distorted octahedral V environment caused by the incorporation of Ru and Ir. Theoretical calculations further confirm that Ru or Ir doping could optimize the adsorption energy of intermediates in the Volmer and Heyrovsky steps for HER and accelerate the whole kinetic process for OER.

Abstract: The purpose of this work is the structural analysis of graphene oxide (GO) and by means of a new structural model to answer the questions arising from the Lerf–Klinowski and the Lee structural models. Surface functional groups of GO layers and the oxidative debris (OD) stacked on them were investigated after OD was extracted. Analysis was performed successfully using Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-Vis), X-ray photoemission spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDX), Raman spectroscopy, solid-state nuclear magnetic resonance spectroscopy (SSNMR), standardized Boehm potentiometric titration analysis, elemental analysis, X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The analysis showed that graphene oxide layers, as well as oxidative debris contain different functional groups such as phenolic –OH, ketone, lactone, carboxyl, quinone and epoxy. Based on these results, a new structural model for GO layers is proposed, which covers all spectroscopic data and explains the presence of the other oxygen functionalities besides carboxyl, phenolic –OH and epoxy groups.

Abstract: High-resolution spectroscopy (R ≥ 25,000) has recently emerged as one of the leading methods for detecting atomic and molecular species in the atmospheres of exoplanets. However, it has so far been lacking a robust method for extracting quantitative constraints on the temperature structure and molecular/atomic abundances. In this work, we present a novel Bayesian atmospheric retrieval framework applicable to high-resolution cross-correlation spectroscopy (HRCCS) that relies on the cross-correlation between data and models to extract the planetary spectral signal. We successfully test the framework on simulated data and show that it can correctly determine Bayesian credibility intervals on atmospheric temperatures and abundances, allowing for a quantitative exploration of the inherent degeneracies. Furthermore, our new framework permits us to trivially combine and explore the synergies between HRCCS and low-resolution spectroscopy to maximally leverage the information contained within each. This framework also allows us to quantitatively assess the impact of molecular line opacities at high resolution. We apply the framework to VLT CRIRES K-band spectra of HD 209458 b and HD 189733 b and retrieve abundant carbon monoxide but subsolar abundances for water, which are largely invariant under different model assumptions. This confirms previous analysis of these data sets, but is possibly at odds with detections of H2O at different wavelengths and spectral resolutions. The framework presented here is the first step toward a true synergy between space observatories and ground-based high-resolution observations.

Abstract: The synthesis of a novel In2O3/In2S3 microsphere heterostructures is conducted through a well-designed two-step hydrothermal method. These composites are first applied for efficient fixation of N2 to NH3 under mild conditions without any organic scavengers and precious-metal cocatalysts. Here the In2S3 flakes are in situ generated and uniformly assembled on In2O3 microsphere. The phase structures, morphologies and oxygen vacancies of the samples are systematically characterized by X-ray powder diffraction (XRD), field-emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse-reflectance spectroscopy (DRS), and photoluminescence spectroscopy (PL), Raman, electron spin resonance (ESR) spectroscopy and photoelectrochemistry. Meanwhile, the investigation of photocatalytic performance can confirm that the nitrogen fixation rate of In2O3/In2S3 (III) heterostructure is 40.04 μmol g−1 h−1, which is about 4.7 and 6.0 times higher than that of pure In2O3 and In2S3, respectively.

Abstract: Near-infrared (12,500-4,000 cm-1; 800-2,500 nm) spectroscopy is the hallmark for one of the most rapidly advancing analytical techniques over the last few decades. Although it is mainly recognized as an analytical tool, near-infrared spectroscopy has also contributed significantly to physical chemistry, e.g., by delivering invaluable data on the anharmonic nature of molecular vibrations or peculiarities of intermolecular interactions. In all these contexts, a major barrier in the form of an intrinsic complexity of near-infrared spectra has been encountered. A large number of overlapping vibrational contributions influenced by anharmonic effects create complex patterns of spectral dependencies, in many cases hindering our comprehension of near-infrared spectra. Quantum mechanical calculations commonly serve as a major support to infrared and Raman studies; conversely, near-infrared spectroscopy has long been hindered in this regard due to practical limitations. Advances in anharmonic theories in hyphenation with ever-growing computer technology have enabled feasible theoretical near-infrared spectroscopy in recent times. Accordingly, a growing number of quantum mechanical investigations aimed at near-infrared region has been witnessed. The present review article summarizes these most recent accomplishments in the emerging field. Applications of generalized approaches, such as vibrational self-consistent field and vibrational second order perturbation theories as well as their derivatives, and dense grid-based studies of vibrational potential, are overviewed. Basic and applied studies are discussed, with special attention paid to the ones which aim at improving analytical spectroscopy. A remarkable potential arises from the growing applicability of anharmonic computations to solving the problems which arise in both basic and analytical near-infrared spectroscopy. This review highlights an increased value of quantum mechanical calculations to near-infrared spectroscopy in relation to other kinds of vibrational spectroscopy.

Abstract: The properties of Er3+-doped gallium lanthanum sulphide thin films prepared on a silicon substrate by femtosecond pulsed laser deposition were studied as a function of process temperature. The films were characterised using transition electron microscopy imaging, X-ray diffractometry, Raman spectroscopy, fluorescence spectroscopy, and UV–Vis–NIR spectroscopy. The results show that by increasing the substrate temperature, the deposited layer thickness increases and the crystallinity of the films changes. The room temperature photoluminescence and lifetimes of the 4I13/2→4I15/2 transition of Er3+ are reported in the paper.

Abstract: We report the composition-dependent optical properties of Bi-doped Cs2Ag1–xNaxInCl6 nanocrystals (NCs) having a double perovskite crystal structure. Their photoluminescence (PL) was characterized b...

Abstract: Owing to its low excitation energy and long radiative lifetime, the first excited isomeric state of thorium-229, 229mTh, can be optically controlled by a laser1,2 and is an ideal candidate for the creation of a nuclear optical clock3, which is expected to complement and outperform current electronic-shell-based atomic clocks4. A nuclear clock will have various applications—such as in relativistic geodesy5, dark matter research6 and the observation of potential temporal variations of fundamental constants7—but its development has so far been impeded by the imprecise knowledge of the energy of 229mTh. Here we report a direct measurement of the transition energy of this isomeric state to the ground state with an uncertainty of 0.17 electronvolts (one standard deviation) using spectroscopy of the internal conversion electrons emitted in flight during the decay of neutral 229mTh atoms. The energy of the transition between the ground state and the first excited state corresponds to a wavelength of 149.7 ± 3.1 nanometres, which is accessible by laser spectroscopy through high-harmonic generation. Our method combines nuclear and atomic physics measurements to advance precision metrology, and our findings are expected to facilitate the application of high-resolution laser spectroscopy on nuclei and to enable the development of a nuclear optical clock of unprecedented accuracy. The transition energy of the first excited state of 229Th to the ground state is determined through the measurement of internal conversion electrons to correspond to a wavelength of 149.7 ± 3.1 nanometres.

Abstract: The identification of isotopic labels by conventional macroscopic techniques lacks spatial resolution and requires relatively large quantities of material for measurements. We recorded the vibrational spectra of an α amino acid, l-alanine, with damage-free “aloof” electron energy-loss spectroscopy in a scanning transmission electron microscope to directly resolve carbon-site–specific isotopic labels in real space with nanoscale spatial resolution. An isotopic red shift of 4.8 ± 0.4 milli–electron volts in C–O asymmetric stretching modes was observed for 13C-labeled l-alanine at the carboxylate carbon site, which was confirmed by macroscopic infrared spectroscopy and theoretical calculations. The accurate measurement of this shift opens the door to nondestructive, site-specific, spatially resolved identification of isotopically labeled molecules with the electron microscope.

Abstract: Overall water splitting with photocatalyst particles presents a potentially cost-effective pathway to hydrogen fuel, however, photocatalysts that can compete with the energy conversion efficiency of photovoltaic and photoelectrochemical cells are still lacking. Recently, Goto et al. reported (Joule, 2018, 2(3), 509–520) that Al-doped SrTiO3 microparticles, followed by modification with Rh2−yCryO3 support overall water splitting with 0.4% solar to hydrogen efficiency and with 56% apparent quantum yield at 365 nm. Earlier, based on transient IR spectroscopy results, the improved activity of Al:SrTiO3 had been attributed to the removal of Ti3+ deep recombination sites by the Al3+ ions. Here we use X-ray photoelectron spectroscopy to show that Al3+ incorporation not only reduces the Ti3+ concentration but also diminishes the n-type character of SrTiO3 and shifts the Fermi level to more oxidizing potentials. According to DFT, the electronic structure of Al-doped SrTiO3 depends sensitively on the relative locations of Al3+ and oxygen vacancies sites, with Al3+ ions next to the oxygen vacancies being most effective at suppressing the sub-band gap states. Reduced hole and electron trapping resulting from the elimination of Ti3+ states is confirmed by surface photovoltage spectroscopy and electrochemical scans. These findings not only provide an experimental basis for the superior water splitting activity of Al-doped SrTiO3, under ultraviolet and solar irradiation, but they also suggest that aliovalent doping may be a general method to improve the solar energy conversion properties of metal oxides. Additionally, overall water splitting with a type 1 single bed particle suspension ‘baggie’ reactor under direct sunlight illumination with 0.11% solar to hydrogen efficiency is also demonstrated for the first time. This provides a proof of concept for one of the models in the 2009 US Department of Energy Technoeconomic analysis for photoelectrochemical hydrogen production.

Abstract: The current challenges of sustainable agricultural development augmented by global climate change have led to the exploration of new technologies like nanotechnology, which has potential in providing novel and improved solutions. Nanotools in the form of nanofertilizers and nanopesticides possess smart delivery mechanisms and controlled release capacity for active ingredients, thus minimizing excess run-off to water bodies. This study aimed to establish the broad spectrum antifungal activity of mycogenic selenium nanoparticles (SeNPs) synthesized from Trichoderma atroviride, and characterize the bioactive nanoparticles using UV–Vis spectroscopy, dynamic light scattering (DLS), Fourier transform infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), and high-resolution transmission electron microscopy (HR-TEM). The synthesized nanoparticles displayed excellent in vitro antifungal activity against Pyricularia grisea and inhibited the infection of Colletotrichum capsici and Alternaria solani on chili and tomato leaves at concentrations of 50 and 100 ppm, respectively. The SEM-EDS analysis of the bioactive SeNPs revealed a spherical shape with sizes ranging from 60.48 nm to 123.16 nm. The nanoparticles also possessed the unique property of aggregating and binding to the zoospores of P. infestans at a concentration of 100 ppm, which was visualized using light microscope, atomic force microscopy, and electron microscopy. Thus, the present study highlights the practical application of SeNPs to manage plant diseases in an ecofriendly manner, due to their mycogenic synthesis and broad spectrum antifungal activity against different phytopathogens.

Abstract: We have carried out a detailed study of the morphological, structural, optical and magnetic properties of Cr doped TiO2 nanocrystals with doping concentrations varying from 3 to 12 atomic weight%. The results obtained from transmission electron microscopy analysis, size–strain plots of all the Cr-doped samples and crystallite size estimation reveal the particle size of the prepared nanocrystals to be well below 10 nm, which is observed to exhibit a decreasing trend with an increase in the Cr dopant concentration. All the samples crystallize in the anatase tetragonal phase of TiO2, which is confirmed from the Rietveld refinement of the X-ray diffraction patterns and the different modes present in the Raman spectra. The Eg(1) mode shows a clear red shift and broadening with increase in the Cr concentration, which indicates the replacement of Ti ions with Cr ions in the TiO2 lattice. The possibility of the presence of different functional groups present is verified by Fourier transform infra-red spectroscopy. The presence of Cr3+ and Ti4+ is confirmed from the X-ray photoelectron spectroscopy (XPS) results suggesting the formation of oxygen vacancies to compensate for the charge neutrality. The XPS results validate the Cr3+ existence in the Cr:TiO2 system and corroborate with a slight peak shift towards lower diffraction angle and further confirm the substitutional doping in the present case. Enhanced visible range optical absorption and a clear red shift associated with the absorption edge also suggest the incorporation of Cr3+ ions into the host system. The estimated band-gap of Cr-doped TiO2 nanocrystals reveals a decreasing trend with increasing Cr concentration. The Urbach energy associated with all the Cr-doped samples signifies the presence of oxygen vacancy related defects in the present system, which is further verified using photoluminescence (PL) spectra, and the deconvolution of the PL spectra provides an insight into the oxygen vacancy defects associated with the system. Paramagnetic (PM) behaviour is observed with an increase in the PM moment, suggesting the increase in isolated Cr ions with increase in the Cr concentration, which is further explained using a bound magnetic polaron (BMP) model. Isolated BMP formation could be the reason for the observed PM behavior of the present system, where the trapping of 3d electrons associated with Cr3+ in the vacancy sites could ultimately lead to fewer overlapped BMPs, yielding a net PM moment. The present Cr:TiO2 system could be modified with tailored optical and magnetic properties for functional applications such as magneto-optics and optoelectronic devices.

Abstract: Probing matter with light in the mid-infrared provides unique insight into molecular composition, structure, and function with high sensitivity. However, laser spectroscopy in this spectral region lacks the broadband or tunable light sources and efficient detectors available in the visible or near-infrared. We overcome these challenges with an approach that unites a compact source of phase-stable, single-cycle, mid-infrared pulses with room temperature electric field–resolved detection at video rates. The ultrashort pulses correspond to laser frequency combs that span 3 to 27 μm (370 to 3333 cm−1), and are measured with dynamic range of >106 and spectral resolution as high as 0.003 cm−1. We highlight the brightness and coherence of our apparatus with gas-, liquid-, and solid-phase spectroscopy that extends over spectral bandwidths comparable to thermal or infrared synchrotron sources. This unique combination enables powerful avenues for rapid detection of biological, chemical, and physical properties of matter with molecular specificity.

Abstract: A highly sensitive uric acid (UA) sensor was fabricated using a wet-chemical (co-precipitation) method to prepare doped ZnO/Ag2O/Co3O4 nanoparticles (NPs) and load them onto a glassy carbon electrode (GCE) by an electrochemical approach. The detailed characterization of the NPs was performed by using conventional methods, such as X-ray photoelectron spectroscopy (XPS), ultraviolet-visible spectroscopy (UV-vis.), Fourier-transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), Tunneling electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray powder diffraction (XRD) analysis. Thermal gravimetric analysis (TGA) of the as-prepared ternary NPs was performed in order to study the stability of NPs in different temperature ranges over which the weight loss and thermal effect are significant. During the electrochemical analysis, the proposed UA sensor was found to be linear over a large linear dynamic range (LRD; 0.1 nM–0.01 mM). The analytical performance of the sensor such as sensitivity (82.3323 μA μM−1 cm−2) was estimated from the slope of the calibration curve and the detection limit (89.14 ± 4.46 pM) was calculated at a signal to noise ratio of 3. The proposed UA biosensor showed reliable reproducibility, a short response time (22.0 s), long-term stability, and no interference effects. The ZnO/Ag2O/Co3O4 NPs/GCE sensor was also validated with real biological samples. Thus, this method might be a prospective and reliable method for the future development of enzyme-free biosensors using doped ternary metal oxides in broad scales.

Abstract: (E)-N′-(2-Nitrobenzylidene)-benzenesulfonohydrazide (NBBSH) was prepared from 2-nitrobenzaldehyde and benzenesulfonylhydrazine by using a simple condensation process with medium yield. It was then crystallized in methanol and characterized using various spectroscopic techniques such as Fourier transform infra-red spectroscopy (FTIR), ultra-violet visible spectroscopy (UV-vis), proton nuclear magnetic resonance (1H-NMR), X-ray photoelectron spectroscopy (XPS), and carbon-13 nuclear magnetic resonance (13C-NMR). The structure of the NBBSH molecule was confirmed using the single crystal X-ray diffraction technique (SCXRDT). A thin layer of NBBSH slurry was deposited onto a cleaned and dried flat round surface of GCE with a binding agent (Nafion) to fabricate a sensitive and selective heavy metal ion (HMI) sensor. The fabricated NBBSH/GCE sensor exhibited enhanced sensing performances such as sensitivity, limit of detection (LOD), linear dynamic range (LDR), and long-term stability towards selective arsenic ions. The calibration curve (CC) was found to be linear over a broad range of As3+ conc. (0.1 nM–0.1 M) and the calculated sensitivity and LOD (based on 3N/S) were found to be ∼190.0 pA μM−1 cm−2 and 50.0 pM, respectively. This novel approach can be used as an efficient path for the development of HMI sensors regarding monitoring of hazardous materials in biological and environmental sciences.

Abstract: Context. KELT-9 b exemplifies a newly emerging class of short-period gaseous exoplanets that tend to orbit hot, early type stars – termed ultra-hot Jupiters. The severe stellar irradiation heats their atmospheres to temperatures of ~4000 K, similar to temperatures of photospheres of dwarf stars. Due to the absence of aerosols and complex molecular chemistry at such temperatures, these planets offer the potential of detailed chemical characterization through transit and day-side spectroscopy. Detailed studies of their chemical inventories may provide crucial constraints on their formation process(es) and evolution history.Aims. We aim to search the optical transmission spectrum of KELT-9 b for absorption lines by metals using the cross-correlation technique.Methods. We analysed two transit observations obtained with the HARPS-N spectrograph. We used an isothermal equilibrium chemistry model to predict the transmission spectrum for each of the neutral and singly ionized atoms with atomic numbers between three and 78. Of these, we identified the elements that are expected to have spectral lines in the visible wavelength range and used those as cross-correlation templates.Results. We detect (>5σ ) absorption by Na I, Cr II, Sc II and Y II, and confirm previous detections of Mg I, Fe I, Fe II, and Ti II. In addition, we find evidence of Ca I, Cr I, Co I, and Sr II that will require further observations to verify. The detected absorption lines are significantly deeper than predicted by our model, suggesting that the material is transported to higher altitudes where the density is enhanced compared to a hydrostatic profile, and that the material is part of an extended or outflowing envelope. There appears to be no significant blue-shift of the absorption spectrum due to a net day-to-night side wind. In particular, the strong Fe II feature is shifted by 0.18 ± 0.27 km s−1 , consistent with zero. Using the orbital velocity of the planet we derive revised masses and radii of the star and the planet: M * = 1.978 ± 0.023 M ⊙ , R * = 2.178 ± 0.011 R ⊙ , m p = 2.44 ± 0.70 M J and R p = 1.783 ± 0.009 R J .

Abstract: This paper reports the synthesis of bare TiO2 and various molar concentrations of ruthenium (Ru)-doped TiO2 nanoparticles by the precipitation method. The as-synthesized photocatalysts were characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS), N2 adsorption/desorption techniques, X-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDS), Raman spectroscopy, photoluminescence spectroscopy (PL), and electrochemical measurements. The results from the UV-vis spectroscopy clearly indicated a red-shift of the optical response toward the visible region owing to the reduced band gap energy, thus showing an enhancement of the absorption in the visible spectrum. The XRD study showed that the samples were crystallized with the photoactive anatase phase of TiO2. The microstructural study using Raman spectroscopy indicated that the Ru dopant occupied the substitutional sites in the TiO2 lattice. According to the Mott–Schottky analysis, the flat band potential of the Ru-doped TiO2 was shifted to the negative potential. The photocurrent, electrochemical impedance spectroscopy, and photoluminescence revealed a higher photogenerated charge-carriers separation efficiency of the doped sample. The photocatalytic activities of the bare TiO2 and (0.05–0.2 mol%) Ru-doped TiO2 nanoparticles were examined by studying the hydrogen production from water using methanol as a sacrificial reagent and Pt nanoparticles as a cocatalyst under light of λ ≥ 320. The optimal iron content was determined to be 0.1 mol% and the corresponding hydrogen production rate was 3400 μmol h−1 in aqueous methanol, which is enhanced by more than 2 times compared to bare TiO2 (1500 μmol h−1) under the same reaction conditions. The higher activity for the doped materials was attributed to the presence of the Ru dopant to facilitate the visible-light-driven activity by introducing the electron donor/acceptor level of ruthenium and the mid-band energy level of defects between the conduction band minimum and valence band maximum of TiO2.

Abstract: Perovskite-type oxides lanthanum ferrite (LaFeO3) photocatalysts were successfully prepared by a facile and cost-effective sol-gel method using La(NO)3 and Fe(NO)3 as metal ion precursors and citric acid as a complexing agent at different calcination temperatures. The properties of the resulting LaFeO3 samples were characterized by powder X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDXS), UV-Vis diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectra (IR), transmission electron microscopy (TEM), N2 adsorption/desorption and photoelectrochemical tests. The photoactivity of the LaFeO3 samples was tested by monitoring the photocatalytic degradation of Rhodamine B (RhB) and 4-chlorophenol (4-CP) under visible light irradiation, the highest photocatalytic activity was found for LaFeO3 calcined at 700 °C, which attributed to the relatively highest surface area (10.6 m2/g). In addition, it was found from trapping experiments that the reactive species for degradation were superoxide radical ions (O2−) and holes (h+). Photocurrent measurements and electrochemical impedance spectroscopy (EIS) proved the higher photo-induced charge carrier transfer and separation efficiency of the LaFeO3 sample calcined at 700 °C compared to that that calcined at 900 °C. Band positions of LaFeO3 were estimated using the Mott-Schottky plots, which showed that H2 evolution was not likely.

Abstract: Given its promising electron transportation ability, excellent electrical conductivity, and larger work function (6.2 eV) disclosed by density functional theory calculations, MXene material, O-terminated Ti3C2 has the potential to serve as a perfect cocatalyst. Herein, a novel Ti3C2/SrTiO3 heterostructure based on partly superficial oxidation from precursor multilayered Ti3C2 is developed as a photocatalyst for efficiently photocatalytic reduction and removal of U(VI). Specifically, the composite of 2 wt % Ti3C2/SrTiO3 (0.02 Ti3C2/SrTiO3) exhibits an excellent photocatalytic UO22+ removal rate of 77%, which is nearly 38 times higher than that of the pristine SrTiO3. The enhanced photocatalytic performance of 0.02 Ti3C2/SrTiO3 is systematically identified by photoluminescence spectroscopy, UV–vis diffuse reflectance spectroscopy, Raman spectroscopy, and electrochemical characterizations. The multilayered Ti3C2 as a cocatalyst can facilitate the charge transportation and inhibit the recombination of electro...

Abstract: I present and summarize a software package ("LPipe") for completely automated, end-to-end reduction of both bright and faint sources with the Low-Resolution Imaging Spectrometer (LRIS) at Keck Observatory. It supports all gratings, grisms, and dichroics, and also reduces imaging observations, although it does not include multislit or polarimetric reduction capabilities at present. It is suitable for on-the-fly quicklook reductions at the telescope, for large-scale reductions of archival data-sets, and (in many cases) for science-quality post-run reductions of PI data. To demonstrate its capabilities the pipeline is run in fully-automated mode on all LRIS longslit data in the Keck Observatory Archive acquired during the 12-month period between August 2016 and July 2017. The reduced spectra (of 675 single-object targets, totaling ~200 hours of on-source integration time in each camera), and the pipeline itself, are made publicly available to the community.