Electron Microprobe Research Articles

In Operando study of Microsupercapacitors with Gel Electrolytes using nano‐beam synchrotron X‐ray diffraction.

Synchrotron radiation X‐ray diffraction (XRD) with nanoscale beam size was used here for in situ and in operando study of micro‐supercapacitors (MSC) with gel electrolyte and MXene Ti3C2Tx electrodes. The electrode structure was characterized as a function of applied voltage and distance from the gap separating electrodes using microscopic cells with cylindrical shape designed for transmission mode XRD. The devices with gel electrolytes based on H2SO4 (with H2O/PVA and DMSO/PVA) showed stable performance with no changes in MXene structure under voltage swaps between positive and negative values. Experiments with KI‐based electrolytes demonstrated changes of MXene structure correlated with decrease of energy storage parameters under conditions of increased operation voltage starting from 0.8V. The best performance of MSC was observed when no changes in MXene structure occur after switch of applied voltage polarity. The changes of inter‐layer distance of Mxene upon swap of applied voltage correlate with decrease of device performance and are undesirable for stable operation of MSC’s. We also tested feasibility of X‐ray fluorescence (XRF) for characterization of electrolyte ion migration in MSCs using 2D element mapping. Irreversible sorption of iodine by MXene was found using XRF mapping of charged electrodes using standard in‐plane MSC device and KI electrolyte.

The die for the production of the hammered kaptorgas from Kouřim, Central Bohemia

Kaptorgas were small trapezoidal boxes with lids worn by women and girls in early medieval central Europe as magic or protective amulets. The paper presents a new find of a bronze cast die for hammering the front side of kaptorgas, which was excavated at the Nad Dolnicí settlement site located in the hinterland of the important central Bohemian hillfort of Kouřim. The die was used to produce type 1A kaptorgas with a motif of a four-legged eared gryphon with an indication of a wing and a tail ending in a floral decorative element. Although kaptorgas with this particular motif have not been recorded in Bohemia, it has analogies in Bulgaria and Poland. Based on the stylistic assessment of this originally Mediterranean motif and the chronology of type IA kaptorgas in Bohemia, the die can be dated to the 10th and beginning of the 11th century. X-Ray fluorescence analysis and elemental mapping of the object's surface show that it was made from bronze with a significant lead admixture and a small admixture of zinc. The die is discussed in terms of the spread of Mediterranean motifs and their adaptation by local craftsmen.

MOF-derived porous In2O3 nanospheres sensitized by CdS quantum dots: A ppb-level NO2 sensor with ultra-high response at room-temperature

NO2 is one of the most important atmosphere pollutants, causing great harm to the human body at very low concentrations (ppb levels). Herein, a novel fabrication idea for gas sensing materials was reported to detect ppb-level NO2 via MOF-derived porous In2O3 nanospheres (NSs) sensitized by CdS quantum dots (QDs). The good distribution of CdS QDs (2.5–4.0nm) on porous In2O3 NSs was verified by the transmission electron microscopy and element mapping analyses. In comparison to In2O3 NSs, the CdS@In2O3 composite nanospheres (CNSs) exhibited exceptional responses to ppb-level concentrations of NO2 (S=425.1@100 ppb) at room temperature (RT, 25 ºC), while also demonstrating good selectivity and response reproducibility. These improvements in sensing performance were attributed to the synergies of the electronic effects of CdS QDs, MOF-derived porous nanostructures, and enhanced adsorption of NO2 and active O2– by well-dispersed CdS QDs. This work emphasizes that the MOF-derived In2O3 porous NSs sensitized by CdS QDs can accurately detect ppb-level concentrations of the NO2 at RT.

Efficient oil/water separation using a superhydrophobic polyurethane sponge fabricated by a facile dip-coating method

ABSTRACT Due to the numerous incidents of oil spills and the increase in the production of industrial effluents containing oil, the separation of oil and water has become an important global issue. This research used a simple dip-coating method to fabricate a superhydrophobic polyurethane sponge using SiO2 nanoparticles and vinyl trimethoxy silane. XRD, FESEM, EDX, elemental mapping, FT-IR, DLS, and measurement of mechanical resistance, and water contact angle were used to characterise the desired sponge. The modified polyurethane sponge exhibited a water contact angle of 151.32 ± 1.06°. The sorption capacity of the desired sponge measured for various types of oily pollutants and organic solvents were in the range of 30.50 ± 2.04to 66.80 ± 1.64 g.g−1. The separation efficiency of the polyurethane sponge was in the range of 97.14 ± 0.40 to 99.15 ± 0.30. Furthermore, the ability of the desired sponge to separate the oil in the real effluent of the casting unit of a steel production company was investigated. Also, the reusability and the ability of removing emulsified oil droplets of the modified polyurethane sponge were studied. As a result, the as prepared polyurethane sponge can be considered a sorbent with the potential to separate oily pollutants from water and treat oily industrial wastewater.

Novel self‐doped Pd/Cu bimetals in CMC/PANI composites: Efficient heterogeneous catalyst for cooperative Sonogashira and Sonogashira‐cyclization tandem reactions

A new Pd/Cu bimetal catalyst supported on carboxymethylcellulose/polyaniline (CMC/PANI) composites (Pd/Cu@CMC/PANI) was fabricated to investigate the cooperative effect between Pd/Cu bimetals in Sonogashira reactions. This approach involves the self‐organization of aniline on CMC via H‐bond, enabling in situ oxidative polymerization using Pd(II) and Cu(II) ions as co‐oxidants. Subsequently, Pd and Cu are self‐deposited on the resulting CMC/PANI composites through the interaction of coordination and metathesis. The morphological and compositional analysis of the prepared catalyst was performed using various analytical tools such as ICP‐AES, FT‐IR, XPS, SEM, TEM, EDS, elemental mapping, and TGA. The Pd/Cu@CMC/PANI composite as a cooperative catalyst for the Sonogashira couplings exhibited high catalytic activity with relatively low Pd loading over its monometallic Pd counterpart, demonstrating the cooperative effect between Pd and Cu. Then, this bimetallic catalyst was successfully adapted for Sonogashira‐cyclization tandem reaction for the synthesis of benzofuran with excellent yields. Significantly, the Pd/Cu@CMC/PANI catalyst exhibited thermal stability under the reaction conditions and could be easily retrieved and reused repeatedly for five runs in the model reaction without significant discernible performance degradation.

Transformation of organic to inorganic nitrogen in NH4+-illite-bearing and Ga-Al-REE-rich bituminous coals: Evidence from nitrogen isotopes and functionalities

Nitrogen is one of the most important elements and mainly occurs as organic forms in coal, and in a few cases, in an inorganic form. Organic nitrogen in coal is mainly derived from the proteins of plants and micro-organisms but sources of inorganic nitrogen remain controversial. One hypothesis for the source of inorganic nitrogen is the organic matter of coal, but this lacks strong evidence. In the Daqingshan Coalfield of Inner Mongolia, northern China, an igneous intrusion in the east of the coalfield led to a coal rank increase from the Hailiushu through the Datanhao mines to the Adaohai mine from the west to east, with NH4+-illite being detected in the coals from the Datanhao and Adaohai mines. These coals are highly enriched in Ga, Al, and rare earth elements (REE). This study aims to explore the transformation of organic to inorganic nitrogen in these coals by means of nitrogen isotopes, element distribution in NH4+-illite, and nitrogen functional groups.The analysis of NH4+-illite by Electron Probe Microanalysis (EPMA) indicates partial substitution of nitrogen during the transition from kaolinite to NH4+-illite. Thermal metamorphism has resulted in the organic nitrogen isotope (δ15No) values in coals from the Adaohai Mine being more positive than those in the Datanhao and Hailiushu mines. 15N is more enriched in NH4+-illite than in the associated organic matter. The distribution of nitrogen functional forms showed a decrease in pyrrolic nitrogen (N-5) and an increase in pyridinic nitrogen (N-6) from coals in the Hailiushu to Datanhao and Adaohai mines. Ammonium quaternary nitrogen (N-Q) was detected in the NH4+-illite-bearing samples. This study provides significant evidence for the conversion of organic nitrogen to inorganic nitrogen in coals as a result of thermal metamorphism.

Restoration of the Information on De-colourized Architectural Cyanotypes

Abstract Cyanotypes are known to de-colourize with alkalis; however, not much research has been done to regain the lost information. This research examines two possibilities to bring back the information: one is to utilize elemental mapping by X-ray fluorescence spectroscopy analysis to regain the image non-invasively, and the second, to treat the cyanotype with acidic solutions. Both methods brought back the image to the extent that the information could be obtained. As photo reproductions, one of their greatest values is the information they convey. This research could be significant in that it opens possibilities to regain the lost information.

Shifting the paradigm: a functional hole selective transport layer for chalcopyrite solar cells

Cu(In,Ga)Se2 solar cells with high efficiency rely on Ga grading to mitigate back surface recombination and achieve optimal performance. However, the inhomogeneous absorber has drawbacks, including increased non‐radiative loss and inadequate absorption. Therefore, a paradigm change has been demanded in the literatures, to passivate the back contact by introducing a hole selective transport layer. Here, we demonstrate a functional hole transport structure as an alternative to Ga grading. The novel hole transport structure is prepared as a double layer: co‐evaporated CuGaSe2, covered by In2O3, made by solution combustion synthesis. As demonstrated by micrographs, elemental mapping and photoluminescence spectroscopy, the oxide layer improves thermal stability and prevents Ga diffusion. However, during the absorber deposition process, a complete ion exchange of In and Ga takes place between the two layers. Incorporating this hole‐selective transport layer in co‐evaporated non‐graded CuInSe2 solar cells leads to significantly increased minority carrier lifetime, measured by time resolved photoluminescence from 5 ns to 113 ns, yielding an 80 meV improvement in quasi‐Fermi level splitting, as determined by absolute photoluminescence spectroscopy. The devices are finished with standard buffer/window layers and exhibit improved open circuit voltage, as well as a promising fill factor of over 71%, indicating good hole transport properties. These results experimentally demonstrate the passivation effect of the new hole transport layer as well as its good transport properties. Thus, high‐efficiency solar cells can be achieved without relying on Ga grading, enabled by a functional hole transport layer.This article is protected by copyright. All rights reserved.

Extreme shifts in pyrite sulfur isotope compositions reveal the path to bonanza gold

Pyrite is the most common sulfide mineral in hydrothermal ore-forming systems. The ubiquity and abundance of pyrite, combined with its ability to record and preserve a history of fluid evolution in crustal environments, make it an ideal mineral for studying the genesis of hydrothermal ore deposits, including those that host critical metals. However, with the exception of boiling, few studies have been able to directly link changes in pyrite chemistry to the processes responsible for bonanza-style gold mineralization. Here, we report the results of high-resolution secondary-ion mass spectrometry and electron microprobe analyses conducted on pyrite from the Brucejack epithermal gold deposit, British Columbia. Our δ34S and trace element results reveal that the Brucejack hydrothermal system experienced abrupt fluctuations in fluid chemistry, which preceded and ultimately coincided with the onset of ultra-high-grade mineralization. We argue that these fluctuations, which include the occurrence of extraordinarily negative δ34S values (e.g., -36.1‰) in zones of auriferous, arsenian pyrite, followed by sharp increases of δ34S values in syn-electrum zones of nonarsenian pyrite, were caused by vigorous, fault valve-induced episodic boiling (flashing) and subsequent inundation of the hydrothermal system by seawater. We conclude that the influx of seawater was the essential step to forming bonanza-grade electrum mineralization by triggering, through the addition of cationic flocculants and cooling, the aggregation of colloidal gold suspensions. Moreover, our study demonstrates the efficacy of employing high-resolution, in situ analytical techniques to map out individual ore-forming events in a hydrothermal system.

Pedipalp anatomy of the Australian black rock scorpion, Urodacus manicatus, with implications for functional morphology

Pedipalps – chelate ‘pincers’ as the second pair of prosomal appendages – are a striking feature of scorpions and are employed in varied biological functions. Despite the distinctive morphology and ecological importance of these appendages, their anatomy remains underexplored. To rectify this, we examined the pedipalps of the Australian black rock scorpion, Urodacus manicatus, using a multifaceted approach consisting of microcomputed tomography, scanning electron microscopy, energy dispersive X-ray spectroscopy, and live pinch force measurements. In doing so, we document the following aspects of the pedipalps: (1) the musculature in three dimensions; (2) the cuticular microstructure, focusing on the chelae (tibial and tarsal podomeres); (3) the elemental construction of the chelae teeth; and (4) the chelae pinch force. We recognise 25 muscle groups in U. manicatus pedipalps, substantially more than previously documented in scorpions. The cuticular microstructure – endo-, meso-, and exocuticle – of U. manicatus pedipalps is shown to be similar to other scorpions and that mesocuticle reinforces the chelae for predation and burrowing. Elemental mapping of the chelae teeth highlights enrichment in calcium, chlorine, nickel, phosphorus, potassium, sodium, vanadium, and zinc, with a marked lack of carbon. These elements reinforce the teeth, increasing robustness to better enable prey capture and incapacitation. Finally, the pinch force data demonstrate that U. manicatus can exert high pinch forces (4.1 N), further highlighting the application of chelae in subduing prey, as opposed to holding prey for envenomation. We demonstrate that U. manicatus has an array of adaptions for functioning as a sit-and-wait predator that primarily uses highly reinforced chelae to process prey.

Enhanced corrosion resistance of 9Cr alloy steel via Al alloying in simulated harsh marine atmosphere

The corrosion behaviors of Cr9Ni1 and Cr9Ni1Al in simulated harsh marine atmosphere were studied by dry-wet cyclic test (DWCT). Scanning electron microscopy (SEM), energy disperse spectroscopy (EDS) and electron probe microanalyzer (EPMA) were used to observe the cross-section morphology of rust layer. The composition of corrosion products were analyzed through X-ray diffractometer (XRD) and X-Photoelectron spectroscope (XPS). Electrochemical impedance spectroscopy (EIS) was used to determine the electrochemical properties of rusted samples. The results show that the corrosion rate of both 9Cr alloy steels increases continuously during the initial corrosion process of 576 h, which can be understood from α/γ*>1 of the rust layer and the acidification caused by increased CrO3. Interestingly, the addition of 0.7 % Al reduced the corrosion rate of 9Cr steel by more than 26 %. Al not only generates Al2O3 and Al(OH)3 enriched in the whole rust layer, but also optimizes the rust layer in terms of the Cr distribution, composition of Cr-containing compounds, and α-FeOOH content. Importantly, it is proposed that Al alloying weakens acidification through reducing CrO3 content and partial dissolution of the generated Al(OH)3.

Reinforced MOF/polymer composite based on a copper metal-organic framework supported on nanoporous hyper cross-linked polycalix[4]resorcinarene for the preparation of phthalazine and 4H-pyran heterocycles

The present study has aimed to prepare a novel MOF/polymer composite called PC4RA@PrSi-CA/Cu-MOF to take benefit from the advantages of both Cu-based metal-organic framework (Cu-MOF) and porous polymer based on Cis-calix[4]resorcinarene (PC4RA). Various processes, including preparation of a 3D network of polycalix, modification of polycalix with (3-aminopropyl)trimethoxysilan (APTMS) and citric anhydride (CA), and functionalization of the modified polymer with Cu-MOF nanostructure, respectively, were used for synthesizing MOF/polymer composite. Next, the characterization and confirmation of the polymer-supported Cu-MOF were analyzed using FT-IR, EDS-Mapping, STA, PXRD, FE-SEM, and TEM techniques. In the continuation, two types of heterocycles, including phthalazines and 4H-pyrans, were synthesized to reveal the efficiency of the PC4RA@PrSi-CA/Cu-MOF nanocomposite. The catalyst showed a reasonable performance by providing a satisfactory yield of the desired products (90–99 %) during a short time (8–20 min) under mild and green conditions (50 °C in H2O). Furthermore, the structure of the heterocycles was validated using FT-IR, 1H/13C NMR. Then, the catalyst was successively reused ten times in the model reaction and studied using FT-IR, EDX, TEM, and elemental mapping analyses to demonstrate the catalyst stability in recoverability. According to the results, this heterogenized catalyst can recover several times without a notable drop in stability and activity.

Experimental Investigation of Phase Equilibria in the Al–Mo–Hf Ternary System at 400 °C and 600 °C

This study investigates the phase equilibria of the Al-Mo-Hf ternary system at 400 °C and 600 °C using X-ray diffraction (XRD) and electron probe microanalysis (EPMA/WDS) techniques. Seven three-phase and five two-phase regions were identified at 400 °C, while eight three-phase and four two-phase regions were identified at 600 °C. Despite variations in the solid solubility ranges of certain compounds, the distribution of phase zones in the isothermal cross-section remained consistent at both temperatures. Using the experimental results and logical deductions, isothermal cross-sections were constructed for the Al-Mo-Hf ternary system at 600 °C and 400 °C.

MA-XRF datasets analysis based on convolutional neural network: A case study on religious panel paintings

Macroscopic X-ray fluorescence (MA-XRF) datasets are analyzed using Artificial Neural Networks. Specifically, Convolutional Neural Networks (CNNs) are trained by coupling the spectra acquired during the MA-XRF scan of two religious panel paintings (“icons”) with the associated Ground-Truth counts per characteristic transition line, as they are extracted by X-ray fluorescence fundamental parameters analysis. In total, twenty thousand XRF spectra were used for the CNN training. The trained neural networks were applied to analyze millions of MA-XRF spectra acquired during the scan of religious painting panels by computing the counts per pixel of X-ray characteristic transition lines and creating the elemental transition maps. Comparison of the CNN extracted results to the Ground-Truth (GT) shows remarkable agreement. The successful MA-XRF datasets analysis applying the CNN method paves an analytical path to the direction of the auto-identification of spectral lines, offering the means for the non-experienced XRF analyst to provide a state-of-the-art analysis and supporting the experienced user not to overlook hardly resolved transition lines.

Morphological effect on Core@shell AuAg nanoparticles for detecting p‐aminothiophenol dimerization by surface‐enhanced Raman spectroscopy

AbstractA series of non‐spherical metallic Au and bimetallic core@shell AuAg nanoparticles (NPs) have been synthesized for SERS improvements. The bimetallic core@shell AuAg NPs were obtained through a controlled overgrowth of an Ag shell onto the surface of two types of non‐spherical Au NPs, used as seeds, Au nanooctaheda (Au NOc) and Au nanotriangles (Au NTs). This Ag overgrowth was able to produce bimetallic core@shell structures such as nanocubes and nanopyramids, respectively. Transmission electron microscopy (TEM) was used to determine the particle size and particle morphology for metallic and bimetallic NPs, and energy‐dispersive X‐ray (EDX) elemental mapping analysis confirmed the core@shell structure of the bimetallic NPs. The plasmonic absorption bands exhibited for each nanosystem were observed by UV–vis spectroscopy. The concentration of Au and Ag in the bimetallic systems was determined by inductively coupled plasma mass spectrometry (ICP‐MS). After synthesis and characterization, p‐aminothiophenol (PATP) was used as a model analyte to investigate the surface‐enhanced Raman spectroscopy (SERS) capabilities of the synthesized metallic and bimetallic nanosystems. In PATP, a dimerization reaction to 4,4′‐dimercaptoazobenzene (DMAB) is produced when it is adsorbed onto the surface of certain noble metals. This SERS analysis was performed at 10−4 M of PATP and by using two different laser wavelengths (532 and 785 nm) in all cases. In this context, we were able to detect the dimerization reaction of PATP to DMAB only for the bimetallic structures and under the 532 nm laser line. Moreover, we have found that the dimerization capacity also depends on the nanoparticle morphology.

Effect of water glass treatment for zirconia and silane coupling on bond strength of resin cement.

To evaluate the ability of the water glass treatment to penetrate zirconia and improve the bond strength of resin cement. Water glass was applied to zirconia specimens, which were then sintered. The specimens were divided into water-glass-treated and untreated zirconia (control) groups. The surface properties of the water-glass-treated specimens were evaluated using surface roughness and electron probe micro-analyser (EPMA) analysis. A resin cement was used to evaluate the tensile bond strength, with2 and without a silane-containing primer. After 24h in water storage at 37°C and thermal cycling, the bond strengths were statistically evaluated with t-test, and the fracture surfaces were observed using SEM. The water glass treatment slightly increased the surface roughness of the zirconia specimens, and the EPMA analysis detected the water glass penetration to be 50μm below the zirconia surface. The application of primer improved the tensile bond strength in all groups. After 24h, the water-glass-treated zirconia exhibited a tensile strength of 24.8 ± 5.5MPa, which was significantly higher than that of the control zirconia (17.6 ± 3.5MPa) (p < 0.05). After thermal cycling, the water-glass-treated zirconia showed significantly higher tensile strength than the control zirconia. The fracture surface morphology was mainly an adhesive pattern, whereas resin cement residue was occasionally detected on the water-glass-treated zirconia surfaces. The water glass treatment resulted in the formation of a stable silica phase on the zirconia surface. This process enabled silane coupling to the zirconia and improved the adhesion of the resin cement.

Impact of thermal soil treatment on heavy metal mobility in the context of waste management.

Thermal soil treatment is a well-established remediation method to remove organic contaminants from soils in waste management. The co-contamination with heavy metals raises the question if thermal soil treatment affects heavy metal mobility in soils. In this study, four contaminated soils and a reference sample were subjected to thermal treatment at 105°C, 300°C and 500°C for 7 day. Thermogravimetry and differential scanning calorimetry were used to understand the reactions, and resulting gases were identified by Fourier-transformed infrared spectroscopy. Treated and untreated samples were characterised by X-ray diffraction (XRD) and electron microprobe analysis and subjected to pH-dependent leaching tests, untreated samples additionally by X-ray-fluorescence (XRF) and inductively coupled plasma mass spectroscopy (ICP-MS). Leachates were analysed using ICP-MS and ion chromatography. Maximum available concentrations were used for hydrogeochemical modelling using LeachXS/Orchestra to predict leaching control mechanisms. Leaching experiments show that thermal treatment tends to decrease the mobility at alkaline pH of Pb, Zn, Cd, As and Cu, but to increase the mobility of Cr. In the acidic to neutral pH range, no clear trend is visible. Hydrogeochemical modelling suggests that adsorption processes play a key role in controlling leaching. It is suggested that the formation of minerals with a more negatively charged surface during thermal treatment are one reason why cations such as Pb2+, Zn2+, Cd2+ and Cu2+ are less mobile after treatment. Future research should focus on a more comprehensive mineralogical investigation of a larger number of samples, using higher resolution techniques such as nanoscale secondary ion mass spectrometry to identify surface phases formed during thermal treatment and/or leaching.

Near-infrared radiation of gold–platinum submicron particle-decorated nonwoven mats enhances wound healing: In vitro and In vivo studies

Because of their biocompatibility and unique optical and electrical properties, Pt nanoparticles (NPs) have been extensively utilized in biomedical applications. However, the use of pure Pt NPs is hindered by the high costs of raw material and absorption at ultraviolet wavelengths. To leverage the benefits of Pt particles while mitigating their drawbacks, we applied electrospinning technology to prepare polyacrylonitrile (PAN) nonwoven mats decorated with gold and platinum submicron particles (Au5Pt3 submicron particle-decorated PAN). We examined the surface morphology, elemental composition, and chemical structure of the resultant Au5Pt3-decorated PAN nonwoven mats by field emission scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy, and EDX elemental mapping. When subjected to near-infrared (NIR) illumination, the Au5Pt3-decorated PAN nonwoven mats showed a more stable temperature rise than pure PAN nonwoven mats or Au PAN nonwoven mats. Inductively coupled plasma spectrometry demonstrated that the Au5Pt3-decorated PAN nonwoven mats can release more Pt ions under NIR illumination, reaching concentrations of up to approximately 8 ppm. The Au5Pt3-decorated PAN nonwoven mats exerted positive effects in a wounded mouse model, with or without NIR irradiation: the films did not cause wound adhesion or fibrosis, and excellent skin tissue healing and collagen regeneration were observed. Moreover, when combined with NIR illumination, the Au5Pt3 submicron particle-decorated PAN nonwoven mats more strongly inhibited the growth of Gram-positive and Gram-negative bacteria and more strongly enhanced blood vessel generation, compared with the same mats in the absence of NIR illumination. Regardless of NIR irradiation, the Au5Pt3 submicron particle-decorated PAN nonwoven mats do not show significant damage to the liver or kidney in mice. Overall, treatment with these Au5Pt3 submicron particle-decorated PAN nonwoven mats does not result in toxicity in mice and exerts a positive effect on wound healing when combined with NIR irradiation, with enhanced angiogenesis and collagen regeneration.

Highly Efficient PtSn/Al2O3 and PtSnZnCa/Al2O3 Catalysts for Ethane Dehydrogenation: Influence of Catalyst Pretreatment Atmosphere

Increased demand for ethylene has motivated direct ethane dehydrogenation over Pt-based catalysts. PtSn/γ-Al2O3 and PtSnZnCa/γ-Al2O3 catalysts were investigated with the aim of understanding the effect of the pretreatment environment on the state of dispersed Pt for ethane dehydrogenation. The catalysts were prepared by the impregnation method and pretreated in different environments like static air (SA), flowing air (FA), and nitrogen (N2) atmospheres. A comprehensive characterization of the catalysts was performed using Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), Temperature-Programmed Reduction (TPR), NH3 Temperature-Programmed Desorption (NH3-TPD), X-ray photoelectron spectroscopy (XPS), and Transmission Electron Microscopy (TEM) techniques. The results reveal that the PtSn on Al2O3 catalyst pretreated in the static air environment (PtSn-SA) exhibits 21% ethylene yield with 95% selectivity at 625 °C. XPS analysis found more platinum and tin on the catalyst surface after static air treatment. The overall acidity of the catalysts decreased after thermal treatment in static air. Elemental mapping demonstrated that Pt agglomeration was pronounced in catalysts calcined under flowing air and nitrogen. These factors are responsible for the enhanced activity of the PtSn-SA catalyst compared to the other catalysts. The addition of Zn and Ca to the PtSn catalysts increases the yield of the catalyst calcined in static air (PtSnZnCa-SA). The PtSnZnCa-SA catalyst showed the highest ethylene yield of 27% with 99% selectivity and highly stable activity at 625 °C for 10 h.

Influence of the concentration of KOH-based aqueous electrolyte on the electrochemical behavior of NiO thin film

In this research, we explored the influence of varying concentrations of KOH electrolyte (0.5, 1, and 2 M) on the electrochemical characteristics of Nickel Oxide (NiO) thin film. The deposition of NiO material onto glass and Fluor Tin Oxide (FTO) coated glass substrates was achieved through the chemical spray pyrolysis method. Subsequent examinations encompassed structural, morphological, optical, and electrochemical assessments, employing X-ray diffraction (XRD), Raman spectroscopy, Scanning Electron Microscopy coupled with Energy Dispersive X-ray Spectroscopy (SEM-EDS), UV-VIS-NIR spectrophotometry, and cyclic voltammetry (CV), respectively. XRD analysis unveiled a polycrystalline cubic structure of NiO with a preference for orientation along the (111) plane. Raman spectroscopy confirmed the presence of the NiO phase, whereas SEM images depicted the emergence of interconnected nanograins with occasional minor cracks. EDS examination and elemental mapping further substantiated a homogeneous dispersion of elements. Optical analysis disclosed a band gap energy of 3.54 eV and an average transmittance of 71 % in the visible range. Electrochemical analysis indicated that the specific capacitance reached its peak at [1 M] (70 F. g−1). The [2 M] electrolyte exhibited the highest optical modulation (29 %), the most substantial charge density (Qi = 9.5 mC/cm2), and the most favorable switching kinetics. However, the coloration efficiency slightly decreased from 30.94 cm2/C in [1 M] to 30.47 cm2/C in the [2 M] solution, despite these improvements.