Abstract The need for accurate quantification of lead concentrations in urban centers around the world is turning attention towards rapid methods for contamination assessment. Portable X‐ray Fluorescence (pXRF) has been recognized as a more accessible alternative to traditional digestion methods. This study was conducted to produce measurement corrections for in‐situ pXRF measurements conducted on field soils under varying conditions of moisture, organic matter (OM) content, and particle size heterogeneity. Urban forest soils were analyzed for Pb under increasing soil moisture, OM, and coarse fraction contents with two different pXRF and the results were compared to reverse aqua regia digestions. While both instruments showed a strong correlation despite using different calibration methods, correction of pXRF data to digestion values improved accuracy but potentially underestimated Pb concentrations. We propose an empirical correction equation derived from the regression of variance between theoretical and observed concentrations to correct for moisture effects. OM and particle size heterogeneity did not produce a significant effect on Pb measurement and did not warrant correction. Our study confirms other work showing that pXRF provides an accurate and precise alternative to traditional digestion methods for Pb screening, provided that moisture is corrected.

Abstract Using heterogeneous photocatalysts for harvesting sunlight and converting it for water remediation and splitting are promising to mitigate the possible crisis of environment and energy. Among various composites, the MoS2‐based heterostructures and Ni‐based systems exhibit unique electronic, optical properties and redox capabilities, enabling their roles as photocatalysts. Herein, the impacts of chemical environments on the Ni electronic structures within the MoS2‐Ag‐Ni ternary systems are studied via X‐ray photoemission electron spectroscopy (X‐PEEM). Ni nanoparticles with two different sizes of 70 and 200 nm were loaded to MoS2 flakes with silver buffers as bridges. Heterostructures with a nominal mol percentage of (MoS2)77Ag3.7Ni19.3 were synthesized through an ultrasound‐assisted wet method. The oxidation states and various interfacial interactions of Ni with MoS2 in MoS2‐Ag‐Ni ternary composite are spectromicroscopically determined, combining the X‐ray absorption spectroscopy near Ni L‐edges and the imaging capability of the X‐PEEM. Results showed that Ni mainly retrains its chemical states of metal and native oxidizations without observable electronic features subjected to bonding with the sulfur from the MoS2 flakes. The charge migration channel set up by the Ag buffer thus contributes to electron–hole migrations that facilitate the photocatalytic performance of the ternary system eventually.

The materials project – Database and toolbox for materials science So far, numerous databases have been built around the world that summarize a large number of physical and chemical properties, thermodynamical diagrams, crystal structures, and some other useful experimental and calculated data. It is extremely useful for checking and confirming various properties of known materials and, conversely, for discovering promising candidates for functions and properties of interest. Furthermore, one of the remarkable recent trends is employment of deep learning, which is known as the 3rd generation of artificial intelligence, to explore some knowledge and models using already stored big data and some optimized algorithms. The system also includes a platform for quantum mechanical calculation. The Materials Project, established in 2011 by Professor Kristin Persson of Lawrence Berkeley National Laboratory, is an open-access database. Anyone can register as a user and start using it for free of charge. More than 120,000 users have already registered. From the perspective of X-ray experts, the system should be very interesting, because it includes many experimentally collected X-ray absorption spectra, the crystal structure data, and the related quantum mechanical calculation data. The total number of the registered data exceeds 500,000; X-ray spectra and crystal structure data are nearly 20% and 35%, respectively, and others are more theoretical data, such as the density of states, the bond structures and so forth. The Materials Project organizes seminars and annual workshop as well. All of the archives are available on its Youtube site (https://www.youtube.com/c/MaterialsProject). For further information, visit the following page, https://materialsproject.org/

Abstract To quickly identify maritime sites polluted by heavy metal contaminants, reductions in the size of instrumentation have made it possible to bring an X‐ray fluorescence (XRF) analyzer into the field and in direct contact with various samples. The choice of source‐sample‐detector geometry plays an important role in minimizing the Compton scattering noise and achieving a better signal‐to‐noise ratio (SNR) in XRF measurement conditions, especially for analysis of wet sediments. This paper presents the influence of geometrical factors on a prototype, designed for in situ XRF analysis of mercury (Hg) in wet sediments using a 57 Co excitation source and an X‐ray spectrometer. The unique XRF penetrometer prototype has been constructed and tested for maritime wet sediment. The influence on detection efficiency and SNR of various geometrical arrangements have been investigated using the combination of Monte Carlo simulations and laboratory experiments. Instrument calibration was performed for Hg analysis by means of prepared wet sediments with the XRF prototype. The presented results show that it is possible to detect Hg by K‐shell emission, thus enabling XRF analysis for underwater sediments. Consequently, the XRF prototype has the potential to be applied as an environmental screening tool for analysis of polluted sediments with relatively high concentrations (e.g., >2880 ppm for Hg), which would benefit in situ monitoring of maritime pollution caused by heavy metals.

Abstract To improve the accuracy of the energy‐dispersive electron probe microanalysis (EPMA EDS) without measuring the probe current, it is proposed to normalize the measured analyte net X‐ray intensity to the bremsstrahlung integral energy of the analyzed sample. The integral energy is calculated using a modified Kramers formula, the parameters of which have been refined based on processing the spectra of single‐element samples (4 ≤ Z ≤ 83), acquired in the incident electrons energy range from 10 to 25 keV. The dependence of the bremsstrahlung integral energy on the atomic number of the sample and the incident electrons energy is obtained, and recommendations are given for calculating the mean atomic number of multicomponent samples. It is shown that even with a significant variation (within a factor of 2 or more) of the probe current or the X‐ray gathering solid angle, the use of the proposed normalization method improves the reproducibility of analysis to a value characteristic of measurements at a stable probe current and a standing solid angle. The method is recommended for the development of standardless EPMA EDS.

Abstract X‐ray photoelectron spectroscopy (XPS), X‐ray absorption spectroscopy (XAS) and X‐ray Raman scattering (XRS) spectroscopy are the element‐specific tools providing local electronic and chemical structure insights. XPS is widely used for qualitative/quantitative surface analysis of solids and replaced by synchrotron‐based ambient pressure‐XPS and hard‐XPS to benefit from the advantages of near‐ambient pressures and hard X‐rays to study complex sample environments. XAS is a well‐established soft and hard X‐ray probe to examine the coordination, spin and oxidation states in solids, liquids and gases with high resolutions and short data acquisition time. XRS, using the hard X‐rays of ~10 keV, is preferred to conventional XAS and XPS in the study of soft X‐ray absorption edges such as C, O, Li K‐edges bulk‐sensitively in vacuum‐free medium for energy storage systems during working operations, inner Earth elements under realistic conditions, probing chemical and biological reactions in the liquid phase, C speciation in archeological and paleontological samples and direct tomography. In this study, first the basics of XPS, XAS, and XRS techniques with their advantages and limitations are introduced to provide a general overview. In the Results and Discussion, the particular emphasis is given to the comparison of XPS, XAS, and XRS with the interpretation of the spectroscopic signatures for organic carbonate‐based electrolytes. The computed C 1 s binding energy shifts for ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), and diethyl carbonate (DEC) are presented to discuss the XPS peak assignments and the performed C K‐edge XRS measurements of 1 M LiPF 6 in DMC and EC are given for a detailed discussion of the XRS spectra. C 1 s XPS, C K‐edge XAS, and XRS of PC from the literature are discussed to interpret the spectra of each technique comparatively.

Abstract Energy‐dispersive X‐ray fluorescence (EDXRF) is a physical rapid detection method to analyze the types of elements through the energy characteristics of fluorescent X‐ray particles. When applied to the detection of food element content, it not only needs simple sample pretreatment but also the element measurement time generally does not exceed 10 min to have the accuracy of μg/g, which can greatly reduce the time and cost of detection. Due to the limitations of the EDXRF instrument and measurement mechanism, it has low sensitivity to light elements in food, and the detection sensitivity varies with elements in food element analysis. For example, the detection sensitivity of Ca, Mg, Fe, Zn, Cu and other elements concerned by people is not high when the content is low, and the measurement accuracy is extremely dependent on the detector resolution. However, with the improvement of detector performance and algorithm optimization of EDXRF, the detection limit of this technology can reach 0.1 μg/g, the detection of trace elements has also been improved, which has made a new breakthrough in the field of food element detection. Therefore, this paper reviews that in recent 20 years, in order to overcome the various difficulties of EDXRF in food detection, the hardware optimization of EDXRF (For example, the development of an analyzer without sample preparation can greatly reduce the time required for the detection of food elements, and a series of instruments combined with EDXRF and cluster capillary technology can greatly improve the excitation efficiency of lighter elements in food. The spectrometer with a high‐resolution detector can improve the detection accuracy of target elements with low content in food) and in order to solve the problem of spectrum resolution in food detection, (For example, the wavelet transform method which has good performance in spectrum smoothing, identifying weak peaks and maintaining peak shape is applied to EDXRF spectrum resolution, which can better solve the problem that the X‐ray characteristic peaks of elements with a low atomic number in food are submerged) the reform and innovation of spectrum resolution methods are introduced. This paper summarizes and analyzes the representative application examples of EDXRF in food safety detection, discusses the advantages and disadvantages of EDXRF compared with other rapid detection or food detection methods in different situations, concludes its application conditions, and discusses the application prospect of EDXRF technology in the field of food detection.

Abstract A by‐product of energy‐dispersive X‐ray fluorescence (EDXRF)‐analysis consists of using the ratios of selected X‐ray peaks to determine the thickness of multilayered objects. Three different methods were developed in the past, all because the two main K or L X‐lines from an EDXRF spectrum emitted by a chemical element have a distinct energy and are differently attenuated by an overlying layer. This specific subject has many papers dedicated, but only a few considerations were devoted to the limits of these methods, that is, the range, for example, of gold thickness that can be usefully determined by each method. This paper defines these limits in the specific case of thin gilding (with d < 1 μm). Three typical situations were considered, and the following artefacts were studied: two artefacts on gilded lead, where the gold leaf is superimposed to a white lead pigment, both in the painting “La Fornarina” of Raphael, dated 1520 AD, and in the imperial carriage of Dom Pedro II emperor of Brazil. In this last case, the white lead pigment was painted over the wood structure of the carriage; four artefacts on gilded copper, three crowns and a pendant, from the tomb of the Lady of Cao, from the Moche civilization of the North of Peru, dated around 350 AD; finally, an artefact on gilded silver, a vase from the Chavín civilization of the North of Peru, dated around 1000‐200 BC.