XPS Study of Sulfur and Phosphorus Compounds with Different Oxidation States

Mn-Based Artificial Mitochondrial Complex "VI" Acts as an Electron and Free Radical Conversion Factory to Suppress Macrophage Inflammatory Response

Disturbance in the mitochondrial electron transport chain (ETC) is a key factor in the emerging discovery of immune cell activation in inflammatory diseases, yet specific regulation of ETC homeostasis is extremely challenging. In this paper, a mitochondrial complex biomimetic nanozyme (MCBN), which plays the role of an artificial "VI" complex and acts as an electron and free radical conversion factory to regulate ETC homeostasis is creatively developed. MCBN is composed of bovine serum albumin (BSA), polyethylene glycol (PEG), and triphenylphosphine (TPP) hierarchically encapsulating MnO2 polycrystalline particles. It has nanoscale size and biological properties like natural complexes. In vivo and in vitro experiments confirm that MCBN can target the mitochondrial complexes of inflammatory macrophages, absorb excess electrons in ETC, and convert the electrons to decompose H2O2. By reducing the ROS and ATP bursts and converting existing free radicals, inhibiting NLRP3 inflammatory vesicle activation and NF-κB signaling pathway, MCBN effectively suppresses macrophage M1 activation and inflammatory factor secretion. It also demonstrates good inflammation control and significantly alleviates alveolar bone loss in a mouse model of ligation-induced periodontitis. This is the first nanozyme that mimics the mitochondrial complex and regulates ETC, demonstrating the potential application of MCBN in immune diseases.

A Hexanuclear Gadolinium(III)-Based Nanoprobe for Magnetic Resonance Imaging of Tumor Apoptosis

Magnetic resonance imaging (MRI) is instrumental in the noninvasive evaluation of tumor tissues in patients subjected to chemotherapy, thereby yielding essential diagnostic data crucial for the prognosis of tumors and the formulation of therapeutic strategies. Currently, commercially available MRI contrast agents (CAs) predominantly consist of mononuclear gadolinium(III) complexes. Because there is only one Gd(III) atom per molecule, these CAs often require administration in high doses to achieve the desired contrast quality, which inevitably leads to some adverse events. Herein, we develop a six-nuclei, apoptosis-targeting T1 CA, Gd6-ZnDPA nanoprobe, which consists of a hexanuclear gadolinium nanocluster (Gd6) with an apoptosis-targeting group (ZnDPA). The amplification of Gd(III) by the hexanuclear structure generates its high longitudinal relaxivity (44.67 mM-1 s-1, 1T) and low r1/r2 ratio (0.68, 1T). Based on the Solomon-Bloembergen-Morgan (SBM) theory, this notable improvement is primarily ascribed to a long correlation tumbling time (τR). More importantly, the Gd6-ZnDPA nanoprobe shows excellent tumor apoptosis properties with an enhanced MR signal ratio (∼74%) and a long MRI imaging acquisition time window (∼48 h) in 4T1 tumor-bearing mice. This study introduces an experimental gadolinium-based CA for the potential imaging of tumor apoptosis in the context of MRI.

Synthesis of Efficient S-Scheme Heterostructures Composed of BiPO4 and KNbO3 for Photocatalytic N2 Fixation and Water Purification

The preparation of catalysts with heterojunction structures is a strategy to achieve efficient charge separation and high photocatalytic activity of photocatalysts. In this work, BiPO4/KNbO3 heterostructure photocatalysts were fabricated by a combination of hydrothermal and precipitation methods and subsequently employed in catalyzing N2-to-NH3 conversion and RhB degradation under light illumination. Morphological analysis revealed the effective dispersion of BiPO4 on KNbO3 nanocubes. Band structure analysis suggests that KNbO3 and BiPO4 exhibit suitable band potentials to form an S-scheme heterojunction. Under the joint action of the built-in electric field at the interface, energy band bending, and Coulomb attraction force, photogenerated electrons and holes with low redox performance are consumed, while those with high redox performance are effectively spatially separated. Consequently, the BiPO4/KNbO3 shows enhanced photocatalytic activity. The NH3 production rate of the optimal sample is 2.6 and 5.8 times higher than that of KNbO3 and BiPO4, respectively. The enhanced photoactivity of BiPO4/KNbO3 is also observed in the photocatalytic degradation of RhB. This study offers valuable insights for the design and preparation of S-scheme heterojunction photocatalysts.

Multifunctional sodium lignosulfonate/xanthan gum/sodium alginate/polyacrylamide ionic hydrogels composite as a high-performance wearable strain sensor

Recently, conductive hydrogels have shown great promise in flexible electronics and are ideal materials for the preparation of wearable strain sensors. However, developing a simple method to produce conductive hydrogels with excellent mechanical properties, self-adhesion, transparency, anti-freezing, and UV resistance remains a significant challenge. A novel sodium lignosulfonate/xanthan gum/sodium alginate/polyacrylamide/Zn2+/DMSO (SLS/XG/SA/PAM/Zn2+/DMSO) ionic conductive hydrogel was developed using a one-pot method. The resulting ionic conductive hydrogels have excellent mechanical properties (stress: 0.13 MPa, strain: 1629 %), high anti-fatigue properties, self-adhesion properties (iron: 7.37 kPa, pigskin: 4.74 kPa), anti-freezing (freezing point: -33.49 °C) and UV resistance by constructing a chemical and physical hybrid cross-linking network. In particular, the conductivity of G hydrogel reached 6.02 S/m at room temperature and 5.52 S/m at -20 °C. Thus, the hydrogel was assembled into a flexible sensor that could distinguish a variety of large and small scales human movements, such as joint bending, swallowing and speaking in real time with high stability and sensitivity. Moreover, the hydrogel could be used as electronic skin just like human skin and touch screen pen to write.

Enhancing the Washing Durability and Electrical Longevity of Conductive Polyaniline-Grafted Polyester Fabrics

The demand for wearable electronics has driven the development of conductive fabrics, particularly those incorporating polyaniline (PANI) that is known for its high electrical conductivity, flexibility, and ease of fabrication. However, the limited stability and durability of the conductive fabric, especially during washing, present significant challenges. The drawbacks can be traced by weak physical attachment between the fabric and the conductive coating, leading to a decrease in conductivity over time. These drawbacks significantly impact the fabric's functionality and performance, highlighting the need for effective solutions to enhance its stability and durability. This study focuses on addressing these challenges by employing a thermochemical treatment. A hydrophilic surface of the polyester fabric is obtained after the treatment (hydrolysis), followed by grafting of PANI on it. The adhesion between PANI and the polyester fabrics was found to be enhanced, as proved by contact angle analysis. Furthermore, the PANI-hydrolyzed fabrics (treated) demonstrated stable conductivity (∼10-3 S cm-3) even after 10 washing cycles, showcasing their excellent durability. In comparison, the unhydrolyzed PANI fabric experienced a drop in conductivity by three orders of magnitude. X-ray photoelectron spectroscopy via N 1s core line spectra showed chemical shifts and quantified the level of doping through PANI's protonation level. We found that PANI-hydrolyzed fabrics preserved their dedoping level from 44.77 to 42.68%, indicating improved stability and extension of their electrical properties' lifetime after washing as compared to unhydrolyzed (untreated) fabrics, from 36.99 to 26.61%. This investigation demonstrates that the thermochemical approach can effectively enhance the durability of conductive PANI fabrics, enabling them to withstand the washing process while preserving their electrical endurance.

A novel label-free electrochemical immunosensor for the detection of heat shock protein 70 of lung adenocarcinoma cell line following paclitaxel treatment using l-cysteine-functionalized Au@MnO2/MoO3 nanocomposites

The future trend in achieving precision medicine involves the development of non-invasive cancer biomarker sensors that offer high accuracy, low cost, and time-saving benefits for risk clarification, early detection, disease detection, and therapeutic monitoring. A facile approach for the synthesis of MoO3 nanosheets was developed by thermally oxidizing MoS2 nanosheets in air followed by thermal annealing. Subsequently, Au@MnO2 nanocomposites were prepared using a combined hydrothermal process and in situ chemical synthesis. In this study, we present a novel immunosensor design strategy involving the immobilization of antiHSP70 antibodies on Au@MnO2/MoO3 nanocomposites modified on a screen-printed electrode (SPE) using EDC/NHS chemistry. This study establishes HSP70 as a potential biomarker for monitoring therapeutic response during anticancer therapy. Impedance measurements of HSP70 on the Au@MnO2/MoO3/SPE immunosensor using EIS showed an increase in impedance with an increase in HSP70 concentration. The electrochemical immunosensor demonstrated a good linear response in the range of 0.001 to 1000 ng mL-1 with a detection limit of 0.17 pg mL-1 under optimal conditions. Moreover, the immunosensor was effective in detecting HSP70 at low concentrations in a lung adenocarcinoma cell line following Paclitaxel treatment, indicating its potential for early detection of the HSP70 biomarker in organ-on-a-chip and clinical applications.

Effect of Different Phosphates on Pyrolysis Temperature-Dependent Carbon Sequestration and Phosphorus Release Performance in Biochar

Carbon sequestration is the primary function of biochar. Hence, it is necessary to design biochar with high carbon (C) retention and low C loss. In this study, three P compounds, including KH₂PO₄, Ca(H₂PO₄)₂, and NH₄H₂PO₄, were premixed with corn stalk (1:4, w/w), aiming to produce biochars (CSB+K, CSB+Ca, and CSB+N) with high C sequestration and slow release of P at three temperatures (300, 500, and 700 °C). The addition of all P sources obviously increased C retention, with the order of NH₄H₂PO₄ (65.6-83.5%) > Ca(H₂PO₄)₂ (60.4-78.2%) > KH₂PO₄ (50.1-76.1%), compared with the pristine biochar (47.8-73.6%). The addition of Ca(H₂PO₄)₂ and KH₂PO₄ led to an increase in aromaticity and graphitization, as evidenced by H/C, FTIR, Raman and XPS analysis, whereas an opposite result occurred on CSB+N. Furthermore, all three phosphates reduced C loss of biochars with H₂O₂ oxidation, and CSB+Ca showed the best effect. Ca(H₂PO₄)₂ and KH₂PO₄ pretreated biochars had higher resistance to K₂Cr₂O₇ oxidation and thermal treatment. In contrast, the C loss of NH₄H₂PO₄-added biochar at 500 and 700 °C with K₂Cr₂O₇ oxidation was increased by 54% and 36%, respectively. During the pyrolysis process, Ca(H₂PO₄)₂ was transformed into insoluble Ca₂P₂O₇, leading to the lowest P release rate of CSB+Ca. This study indicates that co-pyrolysis of corn stalk and Ca(H₂PO₄)₂ is optimal for increasing C retention, enhancing C stability and improving slow-release performance of P regardless of pyrolysis temperature.

Fomes fomentarius as a Bio-Template for Heteroatom-Doped Carbon Fibers for Symmetrical Supercapacitors

Nowadays, commercial electric double-layer supercapacitors mainly use porous activated carbons due to their high specific surface area, electrical conductivity, and chemical stability. A feature of carbon materials is the possibility of obtaining them from renewable plant biomass. In this study, fungi (Fomes fomentarius) were used as a bio-template for the preparation of carbon fibers via a combination of thermochemical conversion approaches, including a general hydrothermal pre-carbonization step, as well as subsequent carbonization, physical, or chemical activation. The relationships between the preparation conditions and the structural and electrochemical properties of the obtained carbon materials were determined using SEM, TEM, EDAX, XPS, cyclic voltammetry, galvanostatic measurements, and EIS. It was shown that hydrothermal pretreatment in the presence of phosphoric acid ensured the complete removal of inorganic impurities of raw fungus hyphae, but at the same time, saved some heteroatoms, such as O, N, and P. Chemical activation using H3PO4 increased the amount of phosphorus in the carbon material and saved the natural fungus’s structure. The combination of a hierarchical pore structure with O, N, and P heteroatom doping made it possible to achieve good electrochemical properties (specific capacitance values of 220 F/g) and excellent stability after 25,000 charge/discharge cycles in a three-electrode cell. The electrochemical performance in both three- and two-electrode cells exceeded or was comparable to other biomass-derived porous carbons, making it a prospective candidate as an electrode material in symmetrical supercapacitors.

Highly Selective Microsensor for Monitoring Trace Phosphine in the Environment

Monitoring P flux at the Earth's surface-atmosphere interface has many challenges. Therefore, the development of a technology with high selectivity and high sensitivity to in situ trace PH₃ in aquatic or sedimentary environments has become a priority. Herein, an amperometric PH₃ microsensor meeting the above conditions is developed. The sensor is equipped with a Au-coated Pt working electrode (WE) and a Pt guard electrode (GE) positioned in an outer glass casing. The WE and GE are polarized at a fixed value of +150 mV with respect to a pseudo-reference electrode. The outer casing is filled with an acid electrolyte solution, and the tip is sealed using a thin silicone membrane. Mixed gases from the environment diffuse through the first layer of the silicone membrane, and the major H₂S disruptor is eliminated by a ZnCl₂-propylene carbonate trap positioned in the front of the microsensor. Later, the gases diffuse into an electrolytic solution through the second layer of the silicone membrane, and PH₃ is selectively oxidized into H₃PO₄ on the Au-coated Pt WE. This electrochemical oxidation thereby creates a current that is proportional to the concentration of PH₃ (>2 nmol·L^-1). With the aid of the H₂S trap casing and selective catalysis, the effects of other gases on the microsensor can be ignored in terms of environmental monitoring. An example from the sedimentary profile shows that high PH₃ accumulations are found 13 mm below the sediment surface.

Modified Technogenic Asphaltenes as Enhancers of the Thermal Conductivity of Paraffin

The low thermal conductivity of paraffin and other organic phase change materials limits their use in thermal energy storage devices. The introduction of components with a high thermal conductivity such as graphene into these materials leads to an increase in their thermal conductivity. In this work, we studied the use of inexpensive carbon fillers containing a polycyclic aromatic core, due to them having a structural similarity with graphene, to increase the thermal conductivity of paraffin. As such fillers, technogenic asphaltenes isolated from ethylene tar and their modified derivatives were used. It is shown that the optimal concentration of carbon fillers in the paraffin composite, which contributes to the formation of a structural framework and resistance to sedimentation, is 5 and 30 wt. %, while intermediate concentrations are ineffective, apparently due to the formation of large aggregates, the concentration of which is insufficient to form a strong framework. It has been found that the addition of asphaltenes modified with ammonium persulfate in acetic acid significantly increases the thermal conductivity of paraffin by up to 72%.

Nitrogen-Doped and Sulfonated Carbon Dots as a Multifunctional Additive to Realize Highly Reversible Aqueous Zinc-Ion Batteries

Aqueous zinc-ion batteries (ZIBs) using the Zn metal anode have been considered as one of the next-generation commercial batteries with high security, robust capacity, and low price. However, parasitic reactions, notorious dendrites and limited lifespan still hamper their practical applications. Herein, an eco-friendly nitrogen-doped and sulfonated carbon dots (NSCDs) is designed as a multifunctional additive for the cheap aqueous ZnSO₄ electrolyte, which can overcome the above difficulties effectively. The abundant polar groups (-COOH, -OH, -NH₂ , and -SO₃ H) on the CDs surfaces can regulate the solvation structure of Zn²⁺ through decreasing the coordinated active H₂ O molecules, and thus redistribute Zn²⁺ deposition to avoid side reactions. Some of the negatively charged NSCDs are adsorbed on Zn anode surface to isolate the H₂ O/SO₄ ^2- corrosion through the electrostatic shielding effect. The synergistic effect of the doped nitrogen species and the surface sulfonic groups can induce a uniform electrolyte flux and a homogeneous Zn plating with a (002) texture. As a result, the excellent cycle life (4000 h) and Coulombic efficiency (99.5%) of the optimized ZIBs are realized in typical ZnSO₄ electrolytes with only 0.1 mg mL^-1 of NSCDs additive.

Photodynamic and Its Concomitant Ion-Interference Synergistic Therapies Based on Functional Hierarchically Mesoporous MOFs

Although ion-interference therapy (IIT) has become an intriguing option for cancer treatment, the generation of interference ions on-demand remains a challenge. Herein, a nanoplatform based on hierarchically mesoporous metal-organic frameworks (HMMOFs) is adopted to integrate black phosphorus quantum dots (BPQDs) and meso-tetra(4-carboxyphenyl) porphine (TCPP) to realize controllable phosphate anions (PAs) production in a specific cancerous region for IIT. The uniform large mesopores of HMMOFs could guarantee the selective screening and immobilization of ultra-small and monodispersed BPQDs. The TCPP in microporous domains of HMMOFs could effectively produce ¹ O₂ , which not only serves as photosensitizer for photodynamic therapy (PDT), but also switches on the release of PAs from BPQDs in the adjacent mesoporous domains to trigger the concomitant synergetic IIT. The elaborated nanoplatform (BP@HMUiO-66-TCPP) presents good biocompatibility, biodegradability as well as enhanced synergetic therapeutic effects. In murine models treated with BP@HMUiO-66-TCPP, the tumor inhibition rate is as high as ≈98.24% as compared to that of the control group after 14 days treatment. Moreover, the tumor volumes in the synergetic group are only 19.6% of those in the PDT alone treated group. Such a concept of exogenous photo-controlled synergistic therapeutics might be extended to a broad range of IIT for an improved antitumor efficacy.

Magnetically Recyclable -SO3--Coated Nanoparticles Promote Gas Storage via Forming Hydrates

Efficient gas enrichment approaches are of great importance for the storage and transportation of clean energy and the sequestration of carbon dioxide. Of special interest is the regulated gas hydrate-based method; however, its operation requires adequate additives to overcome the low-storage capacity issue. Thus, this method is not economically feasible or environmentally friendly. In this work, a novel recyclable hydrate promoter of copolystyrene-sodium styrenesulfonate@Fe3O4 (PNS) nanoparticles with an integrated core-shell structure was synthesized through emulsion polymerization. This was found to effectively reduce the induction time of methane hydrate formation by one-third compared with the widely used sodium dodecyl sulfate (SDS); the corresponding gas storage capacity was also comparable, up to 155 v/v. In addition, the PNS nanoparticles showed a good performance in foam inhibition upon hydrate decomposition, which frequently occurred with the use of SDS and other surfactant-based promoters. In particular, the new promoters contributed to a more than 30% increase in CO2 storage capacity, coacting with the fine sediments that mimic a marine environment. This provided further possibilities of sequestering CO2 in the form a gas hydrate under the seafloor. The underlying mechanism was proposed to involve anchored surfactants on the surface and tiny channels between the nanoparticles that lead to rapid hydrate nucleation and controlled growth. The results showed that the integrated magnetically recovering nanoparticles developed in this study could improve the efficiency of gas storage by forming gas hydrates; the excellent recycling performance paved the way for solving the economic and environmental problems encountered in additive usage.

MoO3@MoS2 Core-Shell Structured Hybrid Anode Materials for Lithium-Ion Batteries

We explore a phase engineering strategy to improve the electrochemical performance of transition metal sulfides (TMSs) in anode materials for lithium-ion batteries (LIBs). A one-pot hydrothermal approach has been employed to synthesize MoS₂ nanostructures. MoS₂ and MoO₃ phases can be readily controlled by straightforward calcination in the (200–300) °C temperature range. An optimized temperature of 250 °C yields a phase-engineered MoO₃@MoS₂ hybrid, while 200 and 300 °C produce single MoS₂ and MoO₃ phases. When tested in LIBs anode, the optimized MoO₃@MoS₂ hybrid outperforms the pristine MoS₂ and MoO₃ counterparts. With above 99% Coulombic efficiency (CE), the hybrid anode retains its capacity of 564 mAh g⁻¹ after 100 cycles, and maintains a capacity of 278 mAh g⁻¹ at 700 mA g⁻¹ current density. These favorable characteristics are attributed to the formation of MoO₃ passivation surface layer on MoS₂ and reactive interfaces between the two phases, which facilitate the Li-ion insertion/extraction, successively improving MoO₃@MoS₂ anode performance.

Catalytic Decomposition of Residual Ozone over Cactus-like MnO2 Nanosphere: Synergistic Mechanism and SO2/H2O Interference

Ground-level ozone is an irritant and is harmful to human respiratory and nervous systems. Thus, four manganese oxides with different crystals were hydrothermally synthesized to decompose residual ozone (deO₃) in an ozone synergistic-oxidation system. Among them, a cactus-like MnO₂-IV nanosphere exhibited the highest deO₃ activity, with excellent tolerance to water vapor and SO₂/H₂O, which could maintain >88% deO₃ efficiency in the high-humidity and sulfur-containing conditions. It benefits from the unique morphology, high specific surface area, superior redox properties, oxygen chemisorption capabilities, abundant surface-active hydroxyl species, and low valence Mn species. More importantly, the detailed interference mechanism of O₂/O₃/H₂O/SO₂ molecules on MnO₂-IV was revealed utilizing in situ diffused reflectance infrared Fourier transform spectroscopy and X-ray photoelectron spectroscopy. H₂O generally caused recoverable deactivation, but that caused by SO₂ was irreversible. The synergistic effect of SO₂/H₂O promoted the formation of an unstable sulfate species, thereby deepening the deactivation but inhibiting the irreversible poisoning. Finally, nine specific steps to decompose ozone via surface-active hydroxyl/intermediates were established.

Radio-Oxidation of Electric Cabled Models: Ageing Evaluation at the Atomic Scale

The functionality of electric cables, being the safety components of plants, has to be ensured. In nuclear power plants, when they are in the reactor building, these cables can suffer γ irradiation even in normal operating conditions. Their ageing behaviour needs to be well understood to be able to determine a precise end-of-life criterion. As polymers are the most radiosensitive material of the cables, this paper focuses on the ageing of this kind of material and, more specifically, on the ageing of silane-crosslinked polyethylenes (XLPEs). XLPEs are now one of the most employed polymers to manufacture cables. We performed irradiation under oxidative conditions of several model silane-crosslinked polyethylenes with different additives and filler: at three different doses (0, 67, 220 and 374 kGy) for one dose rate (78 Gy·h−1) and at one dose (67 kGy) for three dose rates (8.5, 78 and 400 Gy·h−1). Modifications in the organic materials were followed by X-ray photoelectron spectroscopy. This analytical technique allows following the evolution of the different chemical products formed under irradiation. A better understanding at the atomic scale of the effect of additives on the degradation of polymers is proposed as a function of the ageing conditions.

Facile preparation protocol of magnetic mesoporous carbon acid catalysts via soft-template self-assembly method and their applications in conversion of xylose into furfural

Furfural is a valuable dehydration product of xylose. It has a broad spectrum of industrial applications. Various catalysts containing SO₃H have been reported for the conversion of xylose into furfural. Nevertheless, the multi-step preparation is tedious, and the catalysts are usually fine powders that are difficult to separate from the suspension. Novel magnetic mesoporous carbonaceous materials (Fe/MC) were successfully prepared via facile self-assembly in a single step. A facile subsequent hydrothermal sulfonation of Fe/MC with concentrated H₂SO₄ at 180°C gave mesoporous carbon bearing SO₃H groups (SO₃H@Fe/MC) without loss of the magnetic properties. Various techniques were employed to characterize the SO₃H@Fe/MC as a candidate catalyst. It showed strong magnetism due to its Fe particles and possessed a 243 m² g^-1 BET-specific surface area and a 90% mesopore volume. The sample contained 0.21 mmol g^-1 of SO₃H and gave a high conversion and an acceptable furfural yield and selectivity (100%, 45% and 45%, respectively) when used at 170°C for 1 h with γ-valerolactone as solvent. The catalyst was easily separated after the catalytic tests by using a magnet, confirming sufficient magneticstability. This article is part of the theme issue 'Bio-derived and bioinspired sustainable advanced materials for emerging technologies (part 2)'.

Phosphate Polymer Nanogel for Selective and Efficient Rare Earth Element Recovery

Demand for rare earth elements (REEs) is increasing, and REE production from ores is energy-intensive. Recovering REEs from waste streams can provide a more sustainable approach to help meet REE demand but requires materials with high selectivity and capacity for REEs due to the low concentration of REEs and high competing ion concentrations. Here, we developed a phosphate polymer nanogel (PPN) to selectively recover REEs from low REE content waste streams, including leached fly ash. A high phosphorus content (16.2 wt % P as phosphate groups) in the PPN provides an abundance of coordination sites for REE binding. In model solutions, the distribution coefficient (K_d) for all REEs ranged from 1.3 × 10⁵ to 3.1 × 10⁵ mL g^-1 at pH = 7, and the sorption capacity (q_m) for Nd, Gd, and Ho were ∼300 mg g^-1. The PPN was selective toward REEs, outcompeting cations (Ca, Mg, Fe, Al) at up to 1000-fold excess concentration. The PPN had a K_d of ∼10⁵-10⁶ mL g^-1 for lanthanides in coal fly ash leachate (pH = 5), orders of magnitude higher than the K_d of major competing ions (∼10³-10⁴ mL g^-1). REEs were recovered from the PPN using 3.5% HNO₃, and the material remained effective over three sorption-elution cycles. The high REE capacity and selectivity and good durability in a real waste stream matrix suggest its potential to recover REEs from a broad range of secondary REE stocks.

Microscopic evidence of strong interactions between chemical vapor deposited 2D MoS2 film and SiO2 growth template

Two-dimensional MoS2 film can grow on oxide substrates including Al2O3 and SiO2. However, it cannot grow usually on non-oxide substrates such as a bare Si wafer using chemical vapor deposition. To address this issue, we prepared as-synthesized and transferred MoS2 (AS-MoS2 and TR-MoS2) films on SiO2/Si substrates and studied the effect of the SiO2 layer on the atomic and electronic structure of the MoS2 films using spherical aberration-corrected scanning transition electron microscopy (STEM) and electron energy loss spectroscopy (EELS). The interlayer distance between MoS2 layers film showed a change at the AS-MoS2/SiO2 interface, which is attributed to the formation of S-O chemical bonding at the interface, whereas the TR-MoS2/SiO2 interface showed only van der Waals interactions. Through STEM and EELS studies, we confirmed that there exists a bonding state in addition to the van der Waals force, which is the dominant interaction between MoS2 and SiO2. The formation of S-O bonding at the AS-MoS2/SiO2 interface layer suggests that the sulfur atoms at the termination layer in the MoS2 films are bonded to the oxygen atoms of the SiO2 layer during chemical vapor deposition. Our results indicate that the S-O bonding feature promotes the growth of MoS2 thin films on oxide growth templates.

Postsynthetically Modified Polymers of Intrinsic Microporosity (PIMs) for Capturing Toxic Gases

Polymers of intrinsic microporosity (PIMs) are promising materials for gas adsorption because of their high surface area, processability, and tailorable backbone. Specifically, nitrile groups on the backbone of PIM-1, an archetypal PIM, can be converted to other functional groups to selectively capture targeted gas molecules. Despite these appealing features of PIMs, their potential has mainly only been realized for the separation of nontoxic gases. Here, we prepared PIM-1 materials modified with carboxylic acid and amidoxime functional groups and investigated their performance as adsorbents for the capture of ammonia (NH₃) and sulfur dioxide (SO₂) gases. After determining the Brønsted acidity or basicity of the PIMs from potentiometric acid-base titrations, which can be correlated with affinity for acidic or basic toxic gases, we explored the uptake capacity toward NH₃ and SO₂, respectively. Gas sorption studies revealed that the carboxylated PIM showed higher affinity toward NH₃ through the incorporation of Brønsted acid sites, while the amidoxime functionalized PIM exhibited affinity toward SO₂ through the installed of slightly basic functional groups. Overall, this study highlights new insight into PIMs as solid sorbent materials for capturing toxic gases, which can be transferred to their potential use in practical applications, such as personal protective equipment or air filtration.

Electrochemical synthesis of a new Bi(iii) complex by anodic oxidation of Bi in an aqueous solution of 4-toluenesulfonic acid

A new complex with a composition [Bi₆O₄(OH)₄](C₇H₇SO₃)₆ is formed on a bismuth plate via electrochemical synthesis at 1.0 V anodic polarization in 0.5 M p-toluenesulfonic acid.

Bi-Sb Nanocrystals Embedded in Phosphorus as High-Performance Potassium Ion Battery Electrodes

The development of high-performance potassium ion battery (KIB) electrodes requires a nanoengineering design aimed at optimizing the construction of active material/buffer material nanocomposites. These nanocomposites will alleviate the stress resulting from large volume changes induced by K⁺ ion insertion/extraction and enhance the electrical and ion conductivity. We report the synthesis of phosphorus-embedded ultrasmall bismuth-antimony nanocrystals (Bi_xSb_1-x@P, (0 ≤ x ≤ 1)) for KIB anodes via a facile solution precipitation at room temperature. Bi_xSb_1-x@P nanocomposites can enhance potassiation-depotassiation reactions with K⁺ ions, owing to several attributes. First, by adjusting the feed ratios of the Bi/Sb reactants, the composition of Bi_xSb_1-x nanocrystals can be systematically tuned for the best KIB anode performance. Second, extremely small (diameter ≈ 3 nm) Bi_xSb_1-x nanocrystals were obtained after cycling and were fixed firmly inside the P matrix. These nanocrystals were effective in buffering the large volume change and preventing the collapse of the electrode. Third, the P matrix served as a good medium for both electron and K⁺ ion transport to enable rapid charge and discharge processes. Fourth, thin and stable solid electrolyte interface (SEI) layers that formed on the surface of the cycled Bi_xSb_1-x@P electrodes resulted in low resistance of the overall battery electrode. Lastly, in situ X-ray diffraction analysis of K⁺ ion insertion/extraction into/from the Bi_xSb_1-x@P electrodes revealed that the potassium storage mechanism involves a simple, direct, and reversible reaction pathway: (Bi, Sb) ↔ K(Bi, Sb) ↔ K₃(Bi, Sb). Therefore, electrodes with the optimized composition, i.e., Bi_0.5Sb_0.5@P, exhibited excellent electrochemical performance (in terms of specific capacity, rate capacities, and cycling stability) as KIB anodes. Bi_0.5Sb_0.5@P anodes retained specific capacities of 295.4 mA h g^-1 at 500 mA g^-1 and 339.1 mA h g^-1 at 1 A g^-1 after 800 and 550 cycles, respectively. Furthermore, a capacity of 258.5 mA h g^-1 even at 6.5 A g^-1 revealed the outstanding rate capability of the Sb-based KIB anodes. Proof-of-concept KIBs utilizing Bi_0.5Sb_0.5@P as an anode and PTCDA (perylenetetracarboxylic dianhydride) as a cathode were used to demonstrate the applicability of Bi_0.5Sb_0.5@P electrodes to full cells. This study shows that Bi_xSb_1-x@P nanocomposites are promising carbon-free anode materials for KIB anodes and are readily compatible with the commercial slurry-coating process applied in the battery manufacturing industry.

Recovery of Lanthanum(III) and Nickel(II) Ions from Acidic Solutions by the Highly Effective Ion Exchanger

The recovery of La(III) and Ni(II) ions by a macroporous cation exchanger in sodium form (Lewatit Monoplus SP112) has been studied in batch experiments under varying HNO₃ concentrations (0.2-2.0 mol/dm³), La(III) and Ni(II) concentrations (25-200 mg/dm³), phase contact time (1-360 min), temperature (293-333 K), and resin mass (0.1-0.5 g). The experimental data revealed that the sorption process was dependent on all parameters used. The maximum sorption capacities were found at CHNO₃ = 0.2 mol/dm³, m = 0.1 g, and T = 333 K. The kinetic data indicate that the sorption followed the pseudo-second order and film diffusion models. The sorption equilibrium time was reached at approximately 30 and 60 min for La(III) and Ni(II) ions, respectively. The equilibrium isotherm data were best fitted with the Langmuir model. The maximum monolayer capacities of Lewatit Monoplus SP112 were equal to 95.34 and 60.81 mg/g for La(III) and Ni(II) ions, respectively. The thermodynamic parameters showed that the sorption process was endothermic and spontaneous. Moreover, dynamic experiments were performed using the columns set. The resin regeneration was made using HCl and HNO₃ solutions, and the desorption results exhibited effective regeneration. The ATR/FT-IR and XPS spectroscopy results indicated that the La(III) and Ni(II) ions were coordinated with the sulfonate groups.

Sulfur doped Li1.3Al0.3Ti1.7(PO4)3 solid electrolytes with enhanced ionic conductivity and a reduced activation energy barrier

Recently, tailored synthesis of solid electrolytes satisfy multiple challenges, i.e. high ionic conductivity and wide (electro)chemical stability window is of great interest. Although both oxide- and sulfide-based solid electrolytes have distinguished merits for meeting such concerns separately, a new solid electrolyte having the excellent aspects of both materials is pursued. Herein, we report the synthesis of a sulfur-doped Li1.3Al0.3Ti1.7(PO4)3 (LATP) solid electrolyte with a NASICON crystal structure that combines elevated ionic conductivity with intrinsic stability against an ambient atmosphere. Sulfur doping was carried out using sulfur-amine chemistry and the system was characterized by XRD, Raman, XPS, ICP-OES, and EDS analyses. Bader charge analysis was carried out with the aid of density functional theory calculations to characterize charge accumulation in the local environment of the bare and sulfur doped LATP structures. Our results indicate that the partial replacement of oxygen with sulfur yields higher ionic conductivity due to the lower electronegativity of sulfur compared to oxygen, which reduces the attraction of lithium ions. The enhanced ionic conductivity of LATP is attributed to a decreased lithium ion diffusion activation energy barrier upon sulfur doping. Compared to bare LATP, the as-prepared sulfur doped LATP powders were shown to decrease the activation energy barrier by 10.1%. Moreover, an ionic conductivity of 5.21 × 10-4 S cm-1 was obtained for the sulfur doped LATP powders, whereas bare LATP had an ionic conductivity of 1.02 × 10-4 S cm-1 at 40 °C.

Detailing the Self-Discharge of a Cathode Based on a Prussian Blue Analogue

Prussian Blue analogues (PBAs) are a promising class of electrode active materials for batteries. Among them, copper nitroprusside, Cu[Fe(CN)5NO], has recently been investigated for its peculiar redox system, which also involves the nitrosyl ligand as a non-innocent ligand, in addition to the electroactivity of the metal sites, Cu and Fe. This paper studies the dynamics of the electrode, employing surface sensitive X-ray Photoelectron spectroscopy (XPS) and bulk sensitive X-ray absorption spectroscopy (XAS) techniques. XPS provided chemical information on the layers formed on electrode surfaces following the self-discharge process of the cathode material in the presence of the electrolyte. These layers consist mainly of electrolyte degradation products, such as LiF, LixPOyFz and LixPFy. Moreover, as evidenced by XAS and XPS, reduction at both metal sites takes place in the bulk and in the surface of the material, clearly evidencing that a self-discharge process is occurring. We observed faster processes and higher amounts of reduced species and decomposition products in the case of samples with a higher amount of coordination water.

Combining surface-sensitive microscopies for analysis of biological tissues after neural device implantation

In order to address the complexity of chemical analysis of biological systems, time-of-flight secondary ion mass spectrometry (ToF-SIMS), x-ray photoelectron spectroscopy (XPS), and x-ray photoemission electron microscopy (XPEEM) were used for combined surface imaging of a biological tissue formed around a surface neural device after implantation on a nonhuman primate brain. Results show patterns on biological tissue based on extracellular matrix (ECM) and phospholipid membrane (PM) molecular fragments, which were contrasted through principal component analysis of ToF-SIMS negative spectrum. This chemical differentiation may indicate severe inflammation on tissue with an early case of necrosis. Quantification of the elemental composition and the chemical bonding states on both ECM-rich and PM-rich features was possible through XPS analysis from survey and high-resolution spectra, respectively. Variable amounts of carbon (68%-80.5%), nitrogen (10%-2.4%), and oxygen (20.8%-16.5%) were detected on the surface of the biological tissue. Chlorine, phosphorous sodium, and sulfur were also identified in lower extends. Besides that, analysis of the C 1s high-resolution spectra for the same two regions (ECM and PM ones) showed that a compromise between C-C (41.8 at. %) and C-N/C-O (35.6 at. %) amounts may indicate a strong presence of amino acids and proteoglycans on the ECM fragment-rich region, while the great amount of C-C (70.1 at. %) on the PM fragment-rich region is attributed to the large chains of fatty acids connected to phospholipid molecules. The micrometer-scale imaging of these chemical states on tissue was accomplished through XPEEM analysis. The C-C presence was found uniformly distributed across the entire analyzed area, while C-N/C-O and C=O were in two distinct regions. The combination of ToF-SIMS, XPS, and XPEEM is shown here as a powerful, noninvasive approach to map out elemental and chemical properties of biological tissues, i.e., identification of chemically distinct regions, followed by quantification of the surface chemical composition in each distinct region.

Reduction-ammoniacal leaching to recycle lithium, cobalt, and nickel from spent lithium-ion batteries with a hydrothermal method: Effect of reductants and ammonium salts

Some inevitable issues of the acid leaching method used to recycle spent lithium-ion batteries (LIBs), such as toxic gas emission, excessive acid-base consumption, inferior metal selectivity and equipment corrosion, have gradually emerged and restricted the promotion and development of this method. It is therefore essential to develop a sustainable closed-loop recycling technology (reduction-ammoniacal method) for spent LIBs. In this study, the effects of various species of ammonia, ammonium salts and reductants on the leaching of Li, Co, Ni, Mn and Al from spent LIBs were investigated with a hydrothermal method. An increase of the electrode potential of the reductant greatly accelerated the selective leaching of Li, Co and Ni, which agreed with the thermodynamic analysis results. The standard electrode potentials of the LiNi_xCo_yMn_1-x-yO₂ (NCM) materials were also determined by using approximate calculations. When using (NH₄)₂SO₃ as a reductant in a one-step leaching process, 100% Co, 98.3% Ni and 90.3% Li were extracted into the ammonia-ammonium chloride solutions. From the kinetics analysis, the surface chemical reaction shrinking core model was found to control the leaching behavior of Li, Co, and Ni in the reduction-ammoniacal leaching process. A shell-core structure was composed of a product layer, a diffusion layer of the solid core and an unreacted core. Species in the product layer reduced the leaching efficiencies of Li, Co, and Ni. The results obtained for this hydrothermal reduction-ammoniacal method applied to recycle spent LIBs provide insights for the design of a high-speed, exceptionally selective, closed-loop recycling technique.

Chemical Changes of Graphene Oxide Thin Films Induced by Thermal Treatment under Vacuum Conditions

Reduction of graphene oxide is one of the most promising strategies for obtaining bulk quantities of graphene-like materials. In this study, graphene oxide was deposited on SiO2 and reduced by annealing at 500 K under vacuum conditions (5 × 10−1 Pa). Here, graphene oxide films as well as their chemical changes upon heating were characterized in depth by X-ray photoelectron spectroscopy, Raman spectroscopy, and scanning electron and atomic force microscopies. From the chemical point of view, the as prepared graphene oxide films presented a large quantity of oxidized functional groups that were reduced to a large extent upon heating. Moreover, residual oxidized sulfur species that originated during the synthesis of graphene oxide (GO) were almost completely removed by heating while nitrogen traces were integrated into the carbon framework. On the other hand, regarding structural considerations, reduced graphene oxide films showed more homogeneity and lower roughness than graphene oxide films.