X-photoelectron Spectroscopy Research Articles

Study on the electrochemical process of Li+/Na+ mixed organic dual-cation battery system

Organic materials have garnered significant attention due to abundant resources, recyclability, and ease of design. However, they are hampered in practical applications by poor conductivity and high solubility. Herein, a lithium metal battery is developed in this work, utilizing the cathode material polyanthraquinonyl sulfide (PAQS) doped with a trace of NaCl. Additionally, the ionic liquid lithium bis-trifluoromethanesulfonimide and lithium metal as the anode. Physicochemical characterizations utilizing Raman spectroscopy and X-photoelectron spectroscopy indicate that both Na+ and Li+ migrate within the cell, forming a dual-cation battery. In addition, the battery displays exceptional rate performance with a capacity of 86 mAh·g−1 at 20 C, which is more than triples the capacity without NaCl, and has excellent cycling performance. Moreover, it retains 98 % capacity after 1000 cycles at 2 C with no significant degradation. This research offers an innovative strategy for developing a high-performance double-cation battery.

Bio-based iron oxide nanoparticles forming bi-functional chitosan composite adsorbent for Cr(VI) decontamination

Iron oxide nanoparticles (IONPs) synthesized in a bio-based route are viable contenders for the removal of Cr(VI) from contaminated water. However, recovery and reuse of these IONPs are challenging and could limit their practical applicability. Herein, reusable and bi-functional composite chitosan (CS) beads (CS/IONPs) are developed by infusing IONPs in the CS matrix and applied for Cr(VI) adsorption and detoxification from synthetic wastewater. CS/IONPs beads were characterized through various analytical techniques: X-ray diffraction, X-ray photoelectron spectroscopy and Scanning electron microscopy. The loading of IONPs varied from 0.1 to 0.25 (% w/v) with Fe(III)/Fe(II) in a molar ratio of 2. Mesoporous (11.65 nm) CS/IONPs beads with a size from 6.6 − 4.31 mm were formed with a specific surface area of 63.67 m2/g compared to 25.42 m2/g for CS beads. Cr(VI) removal of 98.71 % was achieved by CS/IONPs adsorbent within 480 min at the optimal conditions of initial pH 3, CS/IONPs dosage 2.5 g/L, temperature 25 °C, and initial Cr(VI) concentration 150 mg/L. The co-existing cations didn’t affect Cr(VI) adsorption capacity of CS/IONPs beads, though PO43− and SO42− competed slightly with Cr(VI) adsorption. Cr(VI) removal process was spontaneous and exothermic and followed the pseudo-first-order kinetic. CS/IONPs composite beads could adsorb a maximum of 345.53 mg Cr(VI) per g of IONPs as determined by Langmuir isotherm. The used CS/IONPs beads could be regenerated using NaOH for the initial 4 cycles, but about 15.7 % of active sites were reduced afterwards. Cr(VI) removal involves electrostatic interaction, Cr(VI) reduction to Cr(III), Cr(III) adsorption, Cr(III) surface complexation through abundant –NH2 group, and Cr(III) co-precipitation with Fe(III).

Microstructure-armored surface and its tribological effects on ultralow-wear PEEK/PTFE composites

Reducing interfacial energy gradient can improve the anti-wear property and even achieve an ultralow wear performance of polyetheretherketone/polytetrafluoroethylene (PEEK/PTFE) composite. Previous studies have primarily focused on the tribochemical crosslinking of PTFE molecules to reduce interfacial energy gradient which resulted in poor lubricity and lengthy run-in periods of polymer-lubricating systems. Here, we propose and prepare a microstructure-armored surface (MSAS) for directly reducing the interfacial energy gradient for the ultralow-wear PEEK/PTFE composites. The morphological, chemical, and tribological characteristics of the PEEK/PTFE running against MSAS were studied. The results show that MSAS can decrease the friction coefficient of PEEK/PTFE by more than 30 %, while reducing its initial run-in time by over 80 %, accomplished with the lowest wear rate of ∼3.8 × 10−8 mm3/Nm. This represents the best performance observed in PEEK- and PTFE-based tribosystems so far. Scanning electron microscopy, infrared spectroscopy, and X-photoelectron spectroscopy revealed the low interfacial energy gradient consisting of PEEK, PTFE, and carboxylated PTFE contributes to the remarkable performance of PEEK/PTFE-on-MSAS tribosystems. This study provides a new approach to designing ultralow-wear polymer tribosystems with great lubricity and a short run-in period beyond composite design.

Controlled electrochemical hydridation of Ti surfaces – optimisation and electrochemical properties

Ti is used as a construction material in many applications including electrodes in various electrochemical technologies due to its high corrosion stability provided by the stable oxide layer on the surface. However, this oxide layer is also the reason for its resistivity causing high interfacial resistance between components and energy losses. This problem can be solved by various surface modifications such as acid etching or coating with a layer of precious metals. In this study, we present a novel method for controlled hydridation of Ti materials based on a combination of acid etching and cathodic hydridation aimed primarily for surface modification of Ti components for proton exchange membrane water electrolyser. Cathodic polarisation represents the means to increase the amount of Ti hydride and to tune its properties to obtain a Ti surface with low interfacial resistance and preserved corrosion stability. The study investigated the effects of concentration, temperature, time, and current density on cathodic polarization in H2SO4 electrolytes. The resulting samples were characterized by X-ray diffractometry, X-ray photoelectron spectroscopy, cyclic voltammetry, electrochemical impedance spectroscopy, Kelvin probe and temperature-programmed desorption. This allowed finding interesting correlations between the surface composition of the Ti samples and their electrochemical properties.

Development of waste straw modified material to reduce soil N2O emission: An application strategy for adsorption of functional groups

The goal of this study was to enhance the utilization of millet straw and reduce N2O emissions, used the semi-interpenetrating (Semi-IPN) technology to develop a novel straw-based material (CSC-g-PAA/PPVA) through the composite integration of modified straw and linear polymer (PPVA). The fourier-transform infrared, x-ray diffraction, x-photoelectron spectroscopy and scanning electron microscopy techniques were be measured to provide evidence of the structure and morphology characterization of CSC-g-PAA/PPVA. The results demonstrated that it exhibited excellent water absorbency and enhanced the adsorption capacity of inorganic nitrogen, with the maximum adsorption of NH4+ and NO3- were 94.5 mg/g and 70.3 mg/g, respectively. The properties of CSC-g-PAA/PPVA could significantly reduce N2O emissions, which was 42.5–95.7% lower than that of the fertilization groups, demonstrated that the modified material produced in this study had significant potential to reduce greenhouse gas emissions.

Green Synthesis of Fluorescent Carbon Dots from Annona squamosa Leaves: Optical and Structural Properties with Bactericidal, Anti-inflammatory, Anti-angiogenesis Applications.

A hydrothermal method was employed for green synthesis of fluorescent carbon dots (GCDs) from Annona squamosa leaves. The synthesized GCDs were confirmed by microscopic and spectroscopic techniques such as: High Resolution Transmission Electron Microscopy (HR-TEM), Atomic Force Microscopy(AFM), UV-Vis spectrometry, Fluorescence spectrometry, X-Photoelectron Spectroscopy(XPS), X-ray Diffraction spectroscopy(XRD), and Fourier Transform Infrared Spectroscopy(FTIR). The produced GCDs had shown multiple properties, including massiveantibacterial activity at concentration 200μg/ml. The stabilization of human red blood cells served as a method to assess the anti-inflammatory activity. We also looked at how GCDs affected the angiogenesis process. The density of blood vessels wassignificantly decreased after treatment with GCDs, according to the results of the Chorio-Allantoic Membrane assay (p < 0.05). As per the study prepared GCDs from fallen leavesofAnnona squamosahave multifunctional applications.

Water-methane interactions in coal: Insights from molecular simulation

Water distribution can affect the storage and transport of methane in coal. There are many reports involving the distribution of water and methane in coal, but the microscopic mechanism of water-methane interaction is still unclear. In this study, realistic molecular structure models of bituminous and anthracite coals were constructed based on the chemical structures of two coal samples. And the chemical structures were analyzed by solid-state nuclear magnetic resonance, Fourier-transform infrared, and X-photoelectron spectroscopy. Then slit-pore models with different pore sizes were constructed based on the molecular structures to simulate the methane-water interaction in bituminous and anthracite coals. Results show that water molecules tend to form water bridges and water films in the pores of bituminous and anthracite coals, respectively. The significant displacement of pre-adsorbed water by methane was observed through simulation. It is found that the water molecules on the pore surface and the interfaces of small-size water bridges are more easily displaced by methane. In the larger pores, methane molecules mainly drive water molecules to agglomerate larger water bridges in bituminous coal. While methane molecules mainly drive water molecules to cover the pore surface and form a thicker water film in anthracite coal. This study provides new insights into the microscopic distribution and interaction mechanism of fluids in coal.

Synthesis of alkyl polyamine with different functional groups and its montmorillonite swelling inhibition mechanism: Experiment and density functional theory simulation

In this work, low molecular weight alkyl polyamine (tris(2-methylaminoethyl)amine (TSA), hexamethyltris(2-aminoethyl)amine (TTA), nonamethyltris(2-aminoethyl)amine (TQA)) with different functional groups and the same hydrophobic chain was synthesized using tris(2-aminoethyl)amine (TPA). X-ray diffraction, scanning electron microscopy, X-Photoelectron spectroscopy, transmission electron microscopy, contact angle, and density functional theory simulation were used to investigate the montmorillonite swelling inhibition mechanisms. The results of the experiments showed that a small amount of TPA, TSA, TTA, and TQA can significantly reduce the basal spacing of montmorillonite (Mt). The basal spacing of montmorillonite did not change with increasing the inhibitor concentration. The basal spacing of Mt-TPA, Mt-TSA, and Mt-TTA had some differences in the dry and wet states, but there was no difference in Mt-TQA. This observation indicated that TPA, TSA and TTA exhibited a three-dimensional spatial configuration in the lamellar spacing of montmorillonite, while TQA was inserted into the space of montmorillonite layer in a single flat layer. As more amine groups were substituted by the methyl groups, the spatial configuration of inhibitors changes from a three-dimensional to a two-dimensional planar structure. The higher the number of hydrogen atom substitutions in the primary amine group by methyl groups, the larger the contact angle, and the stronger the hydrophobic capacity except for the quaternary ammonium groups. The simulation results indicated that the higher the number of substitutions, the larger the adsorption energy. Therefore, inhibitors with a quaternary amine group would have better inhibition performance.

Mutual effects of Shewanella putrefaciens-montmorillonite and their impact on uranium immobilization.

This study investigated the immobilization behavior of U(VI) by the mixture of Shewanella putrefaciens (S. putrefaciens) and montmorillonite with batch experiment. The relevant mechanisms were discussed based on the experimental results and characterizations. It was found that the immobilization of U(VI) by S. putrefaciens-montmorillonite was inhibited at pH<7.0 and enhanced at pH>7.0. The inhibition effect was due to the aggregation and coverage between S. putrefaciens and montmorillonite, whereas the association of microbial dissolvable organic matters (DOM) on montmorillonite could promote immobilization of U(VI). The evidences of X-photoelectron spectroscopy (XPS) and density functional theory (DFT) simulation confirmed that the carboxyl-, hydroxyl-, nitrogen-based DOM do have the ability to interacted with U(VI). This work highlights a comprehensive and overlook perspective to understand the immobilization behavior of U(VI) in environmental organo-minerals.

Bimetal-organic frameworks MnCo-MOF-74 derived Co/MnO@HC for the construction of a novel enzyme-free glucose sensor

An enzyme-free glucose electrochemical sensor was constructed based on MnCo-based nanoparticles with hierarchical carbon (Co/MnO@HC), which was derived from solvothermal synthesis of MnCo-MOF-74. Detailed characteristics of the as-prepared materials were investigated by scanning electron microscope (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution TEM (HRTEM), energy disperse spectroscopy (EDS) mapping and X-photoelectron spectroscopy (XPS). Then Co/MnO@HC was dropped onto glassy carbon electrode (GCE) to fabricate a novel enzyme-free glucose sensor. The performance of the sensor was studied by cyclic voltammetry (CV) and chronoamperometry, the results showed that the biosensor has good electrocatalytic activity for glucose in the range of 50–900 μM and 1.9–6.9 mM with a sensitivity of 233.8 μA mM−1 cm−2 and a detection limit (S/N = 3) of 1.31 μM. Further, the constructed Nafion/Co/MnO@HC/GCE has been successfully applied to determine glucose in real serum samples, which exhibited excellent reproducibility, anti-interference and stability.

A novel multifunctional fertilizer derived from wasted straw: Synthesis, characteristics and agriculture applications

In order to enhance utilization of millet straw and reduce fertilizer loss, a novel multifunctional fertilizer (MS-g-PAA/PDMUA) was developed using straw cellulose and linear polymer (PDMUA) by semi-interpenetrating technology. The structure and morphology characterization of MS-g-PAA/PDMUA were measured by fourier-transform infrared, x-ray diffraction, x-photoelectron spectroscopy and scanning electron microscopy techniques, to provide evidence of semi-IPNs networks and component interactions, and the results show that the product exhibited excellent water absorbency (562.3 g/g) and enhanced the soil infiltration. Cumulative release of N, P was 49.2% and 55.1%, respectively, after 40 days, coming up to the Committee of European Normalization (CEN) standard. The agricultural application of MS-g-PAA/PDMUA showed that it could promote growth indexes of wheat, which could improve wheat yields. Therefore, desirable water retention, slow-release properties, and wheat growth effects highlight the product’s potential for agriculture application.

Direct observation of the active sites in methane dehydroaromatization by NMR

Direct observation of the active sites in methane dehydroaromatization by NMR

Multivalent Amide-Hydrogen-Bond Supramolecular Binder Enhances the Cyclic Stability of Silicon-Based Anodes for Lithium-Ion Batteries.

A supramolecular polymer, poly(N-acryloyl glycinamide) (PNAGA), with a bisamide group on each side of the chain forming multiple amide-hydrogen bonds was synthesized in this work as a binder for silicon (Si)-based anodes. This supramolecular polymer binder with improved mechanical properties presents good interfacial adhesion with Si particles forming hydrogen bonds and enhances the adhesive strength between the electrode material film and the copper current collector. Benefiting from the highly stable inter- and intramolecular multiple amide-hydrogen bonds of the PNAGA binder, the electrode structure maintains integrity and a stable solid electrolyte interphase (SEI) layer is formed on the surface of Si particles. The effect of different binders on the composition of the SEI film was also investigated by X-photoelectron spectroscopy (XPS) characterization. In comparison with polyacrylamide (PAM), which has a similar structure to PNAGA, and the traditional sodium alginate (SA) binder, the Si electrode containing the PNAGA binder shows improved electrochemical performance. The capacity retention is 84% after 100 cycles at 420 mA g-1, and the capacity remains at 1942.6 mAh g-1 after 400 cycles at 1260 mA g-1. Even with a mass loading of 1.2 mg cm-2 Si, the electrode with the PNAGA binder exhibits high initial areal capacity (2.64 mAh cm-2) and good cycling performance (81% capacity retention after 50 cycles). Moreover, the application of the PNAGA binder also brings a stable cycle performance to the commercial Si-graphite (SiC) anode material.

Applicability of CNT as support candidate for thiophene hydrodesulfurization and 1-octene hydrogenation catalyst

The application of carbon nanotubes (CNT) as a support candidate for hydrotreating catalysts for FCC (fluid catalytic cracking) gasoline was researched in the microreactor with a fixed bed at experimental conditions. The CNT synthesized using the AC arc discharge method was functionalized by chemical treatment with nitric acid. Scanning electron spectroscopy (SEM), X-ray diffraction (XRD) and X-photoelectron spectroscopy (XPS) of the functionalized CNT show that during the functionalization of it, HNO3 impurities unwanted for further application were removed and carbon nanostructures haveoxidized, and therefore they have oxide functional groups attached to those walls. At all the conditions observed, the Ni-Mo/CNT catalysts and Co-Mo-0.25 catalyst showed better hydrodesulfurization activities in comparison with the conventional Ni-Mo/γ-Al2O3. As shown in the XRD analysis, the Ni–W/CNT catalysts showed lowest thiophene hydrodesulfurization activity in the temperature range observed, but they showed very good hydrogenation activity on model compounds used.Catalytic performance tests of different catalysts showed that good applicability of the CNT as support candidate for the hydrotreating catalysts. It also was experimentally demonstrated that the Ni-Mo/CNT and Co-Mo/CNT can be the best hydrotreating catalysts.

Decellularized liver matrix-modified chitosan fibrous scaffold as a substrate for C3A hepatocyte culture

A bioreactor filled with functional hepatocytes is a crucial portion of the bio-artificial liver device. However, it is a difficult task to maintain sufficient cell quantity and active hepatocellular function. In this work, we developed a promising scaffold for hepatocyte culture by coating porcine liver extracellular matrix (ECM) on chitosan (CTS) fabrics. Porcine Liver was decellularized using 1% Triton X-100. Solubilized liver ECM was immobilized on CTS fibers surface through cross linking of ECM and CTS with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) and N-Hydroxysuccinimide (NHS). Then the scaffold was characterized by Fourier transformed infrared spectroscopy in attenuated total reflection mode (ATR–FTIR), X-photoelectron spectroscopy (XPS) and water contact angle measurement. The efficacy of modified scaffolds to maintain C3A hepatocytes adhesion, proliferation, bioactivity and functionality in vitro was detected. FTIR spectra and XPS demonstrated the presence of ECM coating on CTS fabric surface. Covalently attached coating significantly improved the binding efficiency between ECM and CTS fabrics, in comparison to the coating by physical absorption. Furthermore, C3A hepatocytes cultured on coated scaffolds showed enhanced cell bioactivity and liver-specific function, such as albumin secretion and urea synthesis, compared with those cultured on untreated scaffolds(p < 0.05). As a promising hepatocyte culture carrier, the ECM coated CTS fabrics could be applied in the biological artificial liver reactor.

Effect of laser surface re-melting on the microstructure and properties of Zr alloy

The effects of laser surface re-melting (LSR) on the mechanical and corrosion properties of Zr-5Ti are investigated. After LSR, the microstructure of the alloy-surface has a finer phase-structure and higher density of grain boundaries. Furthermore, the surface hardness of the Zr-5Ti alloy improves significantly due to grain refinement. With increasing distance from the surface, the hardness decreases gradually because the laths coarsen gradually. Corrosion resistance after LSR also clearly improves due to grain refinement, which also reduces the pitting corrosion sensitivity of the alloy. The generated passivation film of the laser-treated alloy and substrate is also analyzed in this paper using X-photoelectron spectroscopy.

Influence of Leifsonia sp. on U(VI) removal efficiency and the Fe-U precipitates by zero-valent iron.

Zero-valent iron (ZVI) has been widely applied to the remediation of uranium (U)-contaminated water. Notably, indigenous bacteria may possess potential positive or unfavorable influence on the mechanism and stability of Fe-U precipitates. However, the focus of the researches in this field has mainly been on physical and/or chemical aspects. In this study, batch experiments were conducted to explore the effects of an indigenous bacterium (Leifsonia sp.) on Fe-U precipitates and the corresponding removal efficiency by ZVI under different environmental factors. The results showed that the removal rate and capacity of U(VI) was significantly inhibited and decreased by ZVI when the pH increased to near-neutral level (pH = 6~8). However, in the ZVI + Leifsonia sp. coexistence system, the U(VI) removal efficiency were maintained at high levels (over 90%) within the experimental scope (pH = 3~8). This revealed that Leifsonia sp. had a synergistic effect on U(VI) remove by ZVI. According to scanning electron microscope and energy dispersive X-ray detector (SEM-EDX) analysis, dense scaly uranium-phosphate precipitation was observed on ZVI + Leifsonia sp. surface. The X-photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) analysis indicated that Leifsonia sp. facilitated the generation of U(VI)-phosphates precipitates. The X-ray diffraction (XRD) analyses further revealed that new substances, such as (Fe(II)Fe(III)2(PO4)2(OH)2), Fe(II)(UO2)2(PO4)2·8H2O, Fe(II)Fe(III)5(PO4)4(OH)2·4H2O, etc., were produced in the coexisting system of ZVI and Leifsonia sp. This study provides new insights on the feasibility and validity of site application of ZVI to U(VI)-contaminated subsurface water in situ. Graphical abstract.

Photocatalytic Oxidation of SO2 from Flue Gas in the Presence of Mn/Copper Slag as a Novel Nanocatalyst: Optimizations by Box-Behnken Design

One of the principal air pollutants is sulfur dioxide (SO2). The removal of SO2 from flue gas has been one of the key challenges in the control of SO2 emission. In this work, experimental scale photocatalytic oxidation of SO2 is a major process leading to H2SO4 as a new method was suggested on the Liquid phase using Manganese supported on Copper Slag (Mn/CS) under UltraViolet (UV) irradiation. Mn/CS recognized as a novel nanocatalyst for photocatalytic oxidation of SO2 from simulated flue gas. In this study, a Column Packed Photo Catalytic Reactor (CPPCR) was applied. Firstly, the Mn/CS was perpetrated by the impregnation method. Analysis of X-Ray Diffraction (XRD), Field Scanning Electron Microscopy (FESEM), Energy Dispersive X-ray (EDX), FT-IR and X-Photoelectron Spectroscopy (XPS) were used for detection structure, morphology, and size of a particle of Mn/CS nanocatalyst and mechanism of manganese onto copper slag. FESEM results show a good agreement with those determined by the XPS. Box–Behnken Design (BBD) was used for optimization of variables, such as gas flow rate (L/min), Temperature (°C), Reaction time (min) and SO2 concentration (mg/L). Removal of SO2 under the optimal conditions, (8.1414, 25, 60 and 3.94) for Gas flow rate, Temperature, Reaction time and SO2 Concentration respectively were obtained. The most efficiency SO2 removal achieved at the optimal operating conditions is around 99%. It is concluded that the usage of this photocatalytic oxidation of SO2 process, can significantly reduce SO2 air pollution.

A facile hydrothermal synthesis of CeO2 nanocubes decorated ZnO nanostructures: optical and enhanced photocatalytic properties

Synthesis of CeO2, ZnO, and CeO2 nanocubes decorated on the surface of ZnO ovals via a simple hydrothermal method was investigated. The crystalline nature and purity of CeO2, ZnO and CeO2 decorated ZnO were confirmed through X-ray diffraction (XRD) by the co-existence of cubic and hexagonal wurtzite phase of CeO2 and ZnO, respectively. The transmission electron microscopy (TEM) images revealed that CeO2 nanocubes were well decorated on the surface of ZnO in oval morphology. The optical properties of the prepared materials were investigated using diffuse reflectance spectroscopy (DRS) and photoluminescence (PL) spectra and also, the oxidation species presented in the materials were identified through X-photoelectron spectroscopy (XPS) spectra survey. The photocatalytic activity of CeO2 decorated ZnO nanostructures against methylene blue (MB) as a model pollutant under visible light irradiation was enhanced when compared to those of the pure CeO2 and ZnO nanostructures. The reusability of catalyst studies revealed that the efficiency of the visibility light degradation of MB was increased upon the CeO2 deposited on the ZnO surfaces.

Nonderivatization method for determination of glyphosate, glufosinate, bialaphos, and their main metabolites in environmental waters based on magnetic metal-organic framework pretreatment.

A novel magnetic metal-organic framework composite was prepared by a self-assembly approach. The material properties were characterized by Fourier-transform infrared spectroscopy, vibrating sample magnetometry, thermogravimetry and differential thermogravimetric analysis, and X-photoelectron spectroscopy. Then, the as-prepared material was used as an adsorbent and indicated great enrichment ability toward glyphosate, glufosinate, bialaphos, and their main metabolites aminomethylphosphonic acid and 3-methylphosphinicopropionic acid. Based on this, an efficient magnetic solid-phase extraction method combined with ultra high performance liquid chromatography with high-resolution mass spectrometry for the pretreatment and determination of five target compounds in environmental waters was established. Parameters that could impact on the adsorption performance had been studied in detail. The proposed method was successfully applied for the simultaneous determination of glyphosate, glufosinate, bialaphos, and their main metabolites aminomethylphosphonic acid and 3-methylphosphinicopropionic acid in environmental water with recoveries in range of 86.2-104.6% with relative standard deviations less than 10%. Desired linearity was achieved varying from 1 to 100μg/L for five target analytes, respectively. The limits of detection were between 0.01 and 0.03μg/L.