Chemical Stability Research Articles

First principles investigation for the hydrogen storage properties of novel lithium-based XLiH3 (X=K, Rb) perovskite-type hydrides for advance hydrogen storage system

In this work, the density functional theory is used to investigate the structural, mechanical, electronic, dynamic, thermodynamic, optical and hydrogen storage properties of XLiH3 (X=K, Rb) for the first time. Both KLiH3 and RbLiH3 materials exhibit dynamic, mechanical and thermodynamic stability. The lattice parameters of KLiH3 and RbLiH3 are 3.908 and 4.070 Å, respectively. The investigation of Cauchy pressure, Poisson's ratio and B/G ratio shows that KLiH3 and RbLiH3 are brittle materials. Moreover, the electronic properties of XLiH3 hydrides demonstrate that KLiH3 and RbLiH3 show metallic nature. Optical properties of these compounds are studied and reveal that they have very high refractive indexes and dielectric functions. The thermodynamic properties, including heat capacity, entropy, enthalpy, and free energy of XLiH3, are investigated as well. The hydrogen storage capacities of KLiH3 and RbLiH3 are 5.805 and 3.071 wt%, respectively, confirming that KLiH3 has a high hydrogen storage capacity and is more suitable as a hydrogen storage material. Our study opens up a new-pathway for designing novel hydrogen storage materials.

A Polyacrylate Cotton-based Pipette Tip Micro-solid-phase Extraction Technique Coupled with High-performance Liquid Chromatography for Carvedilol Determination in Aqueous Media

Introduction: In this work, a polyacrylate polymer was synthesized into a pipette tip containing cotton fibers and used to extract carvedilol from water and urine samples. Methods: A high-performance liquid chromatography-ultraviolet detection method was developed, which demonstrated the suitability of the purposed pipette tip micro-solid-phase extraction device. Factors affecting the fabrication procedure and polymer quality were studied and optimized. In the next step, the sample preparation process (including extraction and desorption) was fully optimized, and the optimized method was validated. Results: A coating with suitable mechanical and chemical stability was achieved. Its structure was successfully characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. Within-batch and between-batch fabrication reproducibility were obtained at 3.0 and 9.0 %, respectively. The developed method displayed a limit of detection of 1.1 µg L-1 when 1.5 mL of sample was processed, and it was linear in the concentration range of 3.3-350 µg L-1 with LLOQ of 5 µg L-1 . The polyacrylate cotton-based pipette tip was finally used to extract carvedilol from aqueous media with acceptable recoveries of 92-106%. Conclusion: The proposed method is simple and fast and requires low sample volumes. In addition, this method has been evaluated in terms of greenness with three different tools, and the evaluation results with all three tools have shown that this method is one of the green and environmentally friendly methods.

Analysis and characterization of residual salts from lithium carbonate industry: Their potential uses for thermal storage systems

The increasing demand for clean energy and the urgent need to reduce greenhouse gas emissions have led to a growing awareness of the importance of thermal energy storage systems in the diversification of the electric matrix. Sensible heat and latent heat storage are the two main techniques, and the choice of storage system depends on the melting point of the substances and the thermal energy required for the processes. This study focused on waste salts obtained from the production process of lithium carbonate. The thermophysical properties of these salts, including specific heat, density, and thermal stability, were examined through various characterization techniques such as X-ray diffraction, chemical analysis, scanning electron microscopy, thermogravimetry, and differential scanning calorimetry. The results revealed promising thermal properties, chemical stability, and physical availability of the waste salts. Additionally, the study explored the potential benefits of reutilizing these waste salts, such as reducing environmental impact, promoting circular economy principles, and creating new market opportunities for commercial products. Overall, this research provides valuable insights into the thermophysical properties of waste salts from lithium carbonate production. The main results are heat capacity in the solid phase (0.767–3.143 J/g°C) and storable thermal energy (114–1153 TWht). These findings contribute to the design and optimization of thermal energy storage systems, highlighting the potential for sustainable and efficient energy storage solutions in the context of global clean energy transitions.

Stabilizing Effects of Higher-Order Quantum Corrections on Charged BTZ Black Hole Thermodynamics

In this paper, we study the thermodynamic properties and stability of static charged BTZ black holes with the inclusion of higher-order quantum corrections. The corrections to the entropy, mass, and Helmholtz free energy are derived, revealing the intricate interplay between quantum effects and classical gravitational forces in the context of black hole thermodynamics. The study of the specific heat capacity shows that higher-order corrections stabilize the system by removing the instabilities present at lower orders. The analysis of the van der Waals-like isotherms demonstrates the continuous transition from a highly compressible to an almost incompressible regime as the volume is decreased, akin to the behavior of supercritical fluids. Notably, the isotherms do not exhibit any regions of negative compressibility, indicating the absence of instabilities. Furthermore, the convexity of the Helmholtz free energy as a function of volume confirms the stability of the charged BTZ black hole system. These findings provide valuable insights into the complex thermodynamic landscape of three-dimensional black holes and the role of quantum corrections in shaping their behavior.

Efficient degradation of bisphenol A and amino black 10B by magnetic composite Fe3O4@MOF-74 as catalyst

Metal-organic frameworks (MOFs) exhibit high chemical stability and porosity, and have been widely applied in various fields including selective adsorption and separation, sensors, and catalysis. When combined with Fe3O4, they effectively address issues such as aggregation of Fe3O4 particles and the difficulty in recovering MOFs as catalysts. Therefore, in this study, we used a simple solvothermal method as a catalyst to synthesize a high specific surface area magnetic composite Fe3O4@MOF-74, which was used to catalyze the degradation of bisphenol A (BPA) and amino black 10B in wastewater. We activated Na2S2O8 to generate radicals for oxidizing and degrading BPA and amino black 10B. Experimental results showed that at 35 °C, with Fe3O4@MOF-74 (Fe3O4: MOF-74=1:1) concentration of 0.2 g/L and Na2S2O8 concentration of 2 g/L, the catalytic effect is efficient and economical. Meanwhile, removal rates of BPA and amino black 10B exceeded 95.58 % over a broad pH range (pH 3–9). Furthermore, even after multiple cycles of use, Fe3O4@MOF-74 maintained catalytic degradation rates of BPA and amino black 10B above 93.24 % and 95.01 %, respectively. Additionally, in water samples, removal rates of BPA and amino black 10B exceeded 91.55 %. This study provides a new and efficient catalyst material for wastewater treatment, which is expected to play an important role in environmental remediation.

Utilizing frustration in Gd- and Yb-based oxides for milli-Kelvin adiabatic demagnetization refrigeration

Abstract The manifold of energetically degenerate configurations arising from competing interactions in frustrated magnets gives rise to an enhanced entropy at lowest temperatures, which can be utilized for adiabatic demagnetization refrigeration (ADR). We review structural and magnetic properties of various Yb- and Gd-based oxides featuring frustration related to different triangular moment configurations and (for some cases) structural randomness. In comparison to paramagnetic hydrated salts, which have traditionally been employed for mK-ADR, these novel ADR materials enable cooling to temperatures several times lower than the magnetic interaction strength, significantly enhancing the entropy density and cooling power at a given target temperature. A further advantage is their chemical stability, allowing for a much simpler ADR pill design and ultra-high vacuum applications. For the temperature range between 0.02 and 2~K, a systematic comparison of the field-induced entropy density change is provided, that illustrates the advantages of frustrated magnets for low-temperature ADR.

Tunable optical properties of BAs/ZnO vdW heterostructure

Abstract Stacked heterostructures is an effective strategy for physical property modulation and application of novel two-dimensional materials. In this study, a heterostructure consisting of two-dimensional III-V group hexagonal BAs and monolayer of ZnO is presented. The minimum value of binding and cohesive energies screened the BB’ configuration. Phonon spectra and ab initio molecular dynamics (AIMD) simulations further demonstrated the kinetic and thermodynamic stability of the selected model. Most notably, the formation of the heterostructure greatly improves the optical absorption performance of the monolayer, especially in the infrared (IR) regions. At a compressive strain of -6%, the band alignment shifts from type I to type II, while the bandgap becomes dramatically smaller. Refraction and reflection coefficients in the IR region under compressive strain (-2% and -4%) modulation were enhanced significantly. Our results provide theoretical guidance for the design of high-performance photovoltaic devices and solar cells based on BAs/ZnO heterostructures.

Nonplanar Nanographene: A Hydrocarbon Hole-Transporting Material That Competes with Triarylamines.

Hole-transporting materials (HTMs) are essential for optoelectronic devices, such as organic light-emitting diodes (OLEDs), dye-sensitized solar cells, and perovskite solar cells. Triarylamines have been employed as HTMs since they were introduced in 1987. However, heteroatoms or side chains embedded in the core skeleton of triarylamines can cause thermal and chemical stability problems. Herein, we report that hexabenzo[a,c,fg,j,l,op]tetracene (HBT), a small nonplanar nanographene, functions as a hydrocarbon HTM with hole transport properties that match those of triarylamine-based HTMs. X-ray structural analysis and theoretical calculations revealed effective multidirectional orbital interactions and transfer integrals for HBT. In-depth experimental and theoretical analyses revealed that the nonplanarity-inducing annulative π-extension can achieve not only a stable amorphous state in bulk films, but also a higher increase in the highest occupied molecular orbital level than conventional linear or cyclic π-extension. Furthermore, an in-house manufactured HBT-based OLED exhibited excellent performance, featuring superior curves for current density-voltage, external quantum efficiency-luminance, and lifetime compared to those of representative triarylamine-based OLEDs. A notable improvement in device lifetime was observed for the HBT-based OLED, highlighting the advantages of the hydrocarbon HTM. This study demonstrates the immense potential of small nonplanar nanographenes for optoelectronic device applications.

First‐Principles Calculations to Investigate the Structural, Mechanical, Electronic, Optical and Thermal Properties of Disilicides Materials UT2Si2 (T = Ru, Rh, and Pd)

Different physical features of UT2Si2 (T = Ru, Rh, Pd) are investigated using ab initio methods. The examined lattice parameters are closely aligned with the experimental data. The negative cohesive energy ensures the chemical stability of the UT2Si2 (T = Ru, Rh, Pd). The mechanical stability of UT2Si2 (T = Ru, Rh, Pd) is ensured from the positive elastic constants. Very large bulk and Young's moduli of URu2Si2, and URh2Si2 ensures their high resistance to volume and longitudinal deformation. Whereas the lower Young's modulus (E) for UPd2Si2 suggests its heightened capacity to resist thermal shock resistance. The high machinable index of UPd2Si2 compared to URu2Si2 and URh2Si2 confirm its more damage‐tolerant and high elastic behavior and probable industrial applications. All the phases exhibit elastic anisotropy and ductile nature. Metallic features as well as mixture of covalent and ionic bonding are observed from electronic properties. Furthermore, the investigation on optical properties suggests the potential use of UT2Si2 (T = Ru, Rh, Pd) in anti‐reflection coatings, UV detectors, and optoelectronic devices due to their notable peaks in the UV energy range. The thermodynamic parameters such as Debye temperature as well as minimum thermal conductivity indicate the potential utility of these compounds in thermal barrier coating materials.

Nanoemulgel: A Comprehensive Review of Formulation Strategies, Characterization, Patents and Applications

<p>Background: Delivering hydrophobic or poorly soluble drugs has become increasingly challenging, with issues like stability and bioavailability complicating the process. Among various strategies devised to address these problems, nanoemulgels have proven effective. Nanoemulgels combine a gel base and an emulsion at the nanoscale, making them excellent for drug delivery. The nanoemulsion component protects the active ingredient from degradative reactions like hydrolysis and enzymatic degradation. Meanwhile, the gel base enhances the emulsion's thermodynamic stability by increasing the viscosity of the aqueous phase and reducing surface and interfacial tension. </p><p> Objective: The primary objective of this review was to explore nanoemulgels as a drug delivery system in the pharmaceutical industry. It delves into the advantages and applications of nanoemulgels in various medical fields, compares them with conventional emulgel, and examines formulation strategies, preparation methods, patent trends, future prospects, and evaluation methods in detail. </p><p> Method: An exhaustive literature survey was conducted keeping in view the various aspects of nanoemulgel. Information from various resources, such as books, review articles, scientific reports, research articles, and patents, were searched, read, analyzed, and summarized. </p><p> Conclusion: This review article thoroughly examines nanoemulgels, discussing their formulation strategies, characterization techniques, and applications in various fields. It highlights their benefits, such as enhanced drug solubility, controlled release, improved stability, and targeted delivery. The article also covers patents related to nanoemulgel technology and explores its future prospects, emphasizing potential applications in pharmaceuticals, cosmetics, dermatology, and other industries.</p>

Electrical Conductivity, Thermo-Mechanical Properties, and Cytotoxicity of Poly(3,4-Ethylenedioxythiophene):Poly(Styrene Sulfonate) (PEDOT:PSS)/Sulfonated Polyurethane Blends

Electrically conductive polymeric materials have recently garnered significant interest from researchers due to their potential applications in the biomedical field, including medical implants, tissue engineering, flexible electronic devices, and biosensors. Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is considered the most successful conducting polymer due to its higher electrical conductivity and chemical stability, but it suffers from limited solubility in common organic solvents, poor mechanical properties, and low biocompatibility. An area of tremendous interest is in combining PEDOT:PSS with another polymer to form a blend or composite material in order to access the beneficial properties of both materials. However, the hydrophilic nature of PEDOT:PSS makes it difficult to produce composites with non-polar polymers. In order to overcome these problems, we have specifically designed and synthesized two new sulfonated polyurethanes (PUS) with high sulfonic acid functionality. The two polyurethanes, one water-soluble (PUS1) and one water-insoluble (PUS2), were used to make blends with two commercially available PEDOT:PSS formulations (CleviosTM FET and PH1000). Solvent cast films on glass substrates were made from water-soluble PEDOT:PSS/PUS1 blends while free-standing films of PEDOT:PSS/PUS2 blends were fabricated by compression-moulding. Ethylene glycol was used as conductivity enhancer, which showed an increase in the conductivity by several orders of magnitude in most of the compositions investigated. The highest conductivity of 438 S cm−1 was achieved for the blend with 80 wt% of PEDOT:PSS (PH1000) in PUS1.

Investigation of Persistent Photoconductivity of Gallium Nitride Semiconductor and Differentiation of Primary Neural Stem Cells

A gallium nitride (GaN) semiconductor is one of the most promising materials integrated into biomedical devices to play the roles of connecting, monitoring, and manipulating the activity of biological components, due to its excellent photoelectric properties, chemical stability, and biocompatibility. In this work, it was found that the photogenerated free charge carriers of the GaN substrate, as an exogenous stimulus, served to promote neural stem cells (NSCs) to differentiate into neurons. This was observed through the systematic investigation of the effect of the persistent photoconductivity (PPC) of GaN on the differentiation of primary NSCs from the embryonic rat cerebral cortex. NSCs were directly cultured on the GaN surface with and without ultraviolet (UV) irradiation, with a control sample consisting of tissue culture polystyrene (TCPS) in the presence of fetal bovine serum (FBS) medium. Through optical microscopy, the morphology showed a greater number of neurons with the branching structures of axons and dendrites on GaN with UV irradiation. The immunocytochemical results demonstrated that GaN with UV irradiation could promote the NSCs to differentiate into neurons. Western blot analysis showed that GaN with UV irradiation significantly upregulated the expression of two neuron-related markers, βIII-tubulin (Tuj-1) and microtubule-associated protein 2 (MAP-2), suggesting that neurite formation and the proliferation of NSCs during differentiation were enhanced by GaN with UV irradiation. Finally, the results of the Kelvin probe force microscope (KPFM) experiments showed that the NSCs cultured on GaN with UV irradiation displayed about 50 mV higher potential than those cultured on GaN without irradiation. The increase in cell membrane potential may have been due to the larger number of photogenerated free charges on the GaN surface with UV irradiation. These results could benefit topical research and the application of GaN as a biomedical material integrated into neural interface systems or other bioelectronic devices.

Synthesis, Structure, and Light Absorption of Octanoyl Amino Acids

Amino acid lanthanide complexes are a promising class of environmentally friendly and non-toxic optical organic materials that find extensive applications in biomedicine, molecular probes, and optical devices. In this study, three amino acid lanthanide complexes, octanoyl glycine gadolinium (Gd(oct-ala)3×H2O), octanoyl serine gadolinium (Gd(oct-ser)3×H2O), and octanoyl phenylalanine gadolinium (Gd(oct-phe)3×H2O), were synthesized by reacting octanoyl amino acid ligands with gadolinium chloride. The coordination structure of the gadolinium complexes was determined by elemental analysis and infrared spectroscopy. XRD and polarized light microscopy confirmed the amorphous structure of the complexes. DSC and TG-DTA were used to investigate the thermodynamic stability of the gadolinium complexes, and their solubility and UV-visible light absorption properties were also evaluated. Our results demonstrate that all three gadolinium complexes exhibit excellent UV-visible light absorption performance, with the Gd(oct-phe)3×H2O containing a phenyl ring showing the highest light absorption efficiency.

Conducting LixPOy Interface Generated From Insulating Residual Lithium Compounds on LiNi0.8Mn0.1Co0.1O2 Surface Improves Cycle Life and Assists in Fast Cycling.

LiNi0.8Mn0.1Co0.1O2 (NMC811) is the most promising cathode material for future Li-ion batteries (LIBs). However, the bulk and surface structural instabilities retard its commercial success. Surface chemical instability toward exposure to moisture (H2O and CO2) leads to the formation of residual lithium compounds (RLCs: Li2CO3, LiOH) on the surface. The alkaline RLCs form a resistive layer on the surface of NMC811 by undergoing parasitic side reactions with electrolytes. Herein, an "Adverse-to-Beneficial" approach is proposed to eliminate RLCs by chemically transforming them into a LixPOy (Li3PO4 and LiPO3) interface. The interface protects the NMC811 surface from moisture attack and unwanted side reactions with electrolytes. It enhances the cycle life by retaining 70% of the initial capacity after 300 cycles at a 0.5C rate and 60% after 500 cycles, even at a 5C rate in a voltage window of 3.0-4.3V versus Li+/Li. The coexistence of two Li-conducting phases lowers the voltage polarization of the kinetically sluggish H1 → M phase transition to unlock fast cycling, reduces cationic disorder, improves coulombic efficiency, enhances ion diffusion kinetics, and minimizes particle crack formation after long-term cycling. Hence, the LixPOy interface yields multifaceted benefits in the storage, processing, and electrochemistry of NMC811.

Quantification of morphine in exhaled breath condensate using a double network polymeric hybrid hydrogel functionalized with AuNPs

BackgroundMorphine serves as a foundation for creating other opioid derivatives, such as hydro/oxymorphine and heroin, which possess enhanced pain-relieving properties but are also prone to addiction and abuse. In cases of morphine overdose, it not only affects multiple immune functions but can also cause severe health complications. Given these concerns and the widespread use of morphine, it is crucial to develop efficient, uncomplicated, and precise methods for accurately detecting morphine in various biological and pharmaceutical samples.ResultsIn this investigation, a novel gold nanoparticle (AuNPs)-based double network hydrogel (DNH) nanoprobe has been fabricated for sensitive quantification of morphine in exhaled breath condensate samples. For that, gelatin/agarose DNH was fabricated through a one-step heating-cooling method in the presence of AuNPs, providing not only chemical stability but also prevent the AuNPs aggregation during synthesis process. In this method, the absorbance intensity of the nanoprobe gradually decreased with increasing morphine concentration due to the interaction morphine with AuNPs surface plasmon. The aggregation of AuNPs by addition of morphine was verified by UV-Vis spectrophotometry. The sensor displayed high sensitivity with detection limit of 0.006 µg.mL-1 in the linear range from 0.01 to 1.0 µg.mL-1. A reliable performance was attained for the spectrophotometric method for determination of morphine in the real samples.

Decarboxylative and Decarbonylative Borylation of Carboxylic Acids and Their Derivatives†

Comprehensive SummaryBoronate esters are highly valued in synthetic and pharmaceutical industries for their versatility in creating C—C and C—X bonds. They also find applications as catalysts in chemical transformations as well as stimuli‐responsive materials in materials science. Some alkyl boronates themselves also show promising applications in medicinal chemistry. In the past few decades, chemists have been devoted to developing new methods or new starting materials for synthesizing boronate esters. Carboxylic acids and their derivatives are privileged chemical entities due to their readily availability or natural abundance, structural diversity, and chemical stability. Hence, the transformation of carboxylic acid and their derivatives to alkyl/aryl boronate esters has seen its fast development in the past decade. This review summarized the state‐to‐art development of decarboxylative and decarbonylative borylation of carboxylic acids and their derivatives to aryl and alkyl boronate esters. Key ScientistsThe decarboxylative and decarbonylative borylation of carboxylic acids and their derivatives started only in the past decade. In 2016, the decarbonylative borylation of carboxylic esters and amides was reported by Zhuangzhi Shi and Magnus Reuping's groups. Then, in 2017, studies on the decarboxylative borylation of redox‐active esters such as NHPI esters started to receive increasing attention by Aggarwal, Baran, Fu, Glorius, and Li's groups. From 2018 to 2023, large numbers of studies on the decarboxylative and decarbonylative borylation of carboxylic acids and their derivatives using transition‐metal‐catalyst, organo‐catalyst, or under photochemical or electrochemical conditions emerged. Due to space limitations, only pictures of scientists who have contributed more than two works in this area are shown herein.

Accelerated measurement technology quantifying packaging light protection performance for soymilk nutrient and chemical stability

An accelerated in situ (AIS) light exposure and measurement technology for prediction of retail light protection performance of soymilk packaging is reported. The ability of a packaging material to protect light sensitive marker solutions, either comprising riboflavin (RF) or chlorophyll-a (CHLA), from an intense light source was determined. The light-induced decay of the marker was tracked with in situ spectroscopy and modeled to quantify the light protection performance of each packaging material. For a set of packages, chemical analyses (RF, thiobarbituric acid reactive substances (TBARS), hexanal) of packaged soymilk under Simulated Retail (SR) storage conditions demonstrated excellent correlation to the light protection performance data of the same package set determined by AIS (R2 > 0.97). The use of AIS enables rapid quantification of soymilk packaging material light protection performance and the associated preservation of soymilk nutrient and sensory properties, thus it may be applied to improve the design of soymilk packaging materials for light protection performance and contribute towards the improvement of packaged soymilk product shelf life.

Dodecagonal GaN Microrods: Chemical Stability of a‐, m‐, and c‐Plane Walls and Their Application to Water‐Splitting

AbstractPhotoelectrolysis of water is a sustainable option for the production of hydrogen fuel. GaN nano‐ or microstructures are considered for water‐splitting due to their general high chemical stability and high surface‐to‐volume ratio enhancing the process effectiveness. In this study GaN structures with dodecagonal microrods are used as a working electrode for the water‐splitting process. Microrods are grown using a plasma‐assisted molecular beam epitaxy process allowing tailoring of microrod height and density. Their unique property is the of presence twelve sidewalls with alternating a‐ and m‐plane orientations. This enables a simultaneous study of the chemical stability of c‐, a‐, and m‐plane walls of GaN. The water‐splitting process is performed using a 1 mol l−1 NaOH electrolyte solution. Non‐zero current measured at zero bias under illumination indicates that the process takes place. A degradation of the GaN structure is observed after a prolonged process time. In short‐term exposures, etching of microrod sidewalls is observed. Roughening of the a‐plane walls studied by transmission electron microscopy indicates that this orientation is etched with a fastest rate. The internal crystalline structure is not influenced by the etching and remains stable as shown by the X‐ray absorption spectroscopy study.

Chemical Synergic Stabilization of High Br-Content Mixed-Halide Wide-Bandgap Perovskites for Durable Multi-Terminal Tandem Solar Cells with Minimized Pb Leakage.

High Br-content mixed-halide perovskites with wide-bandgap (WBG) of 1.6-2.0 eV have showcased vast potential to be used in tandem solar cells. However, they often suffer from severe halide segregation, phase separation and ion migration issues, which would accelerate the decomposition of perovskites films,deteriorate the photovoltaic performance and even aggravate the lead leakage from damaged devices. Here, we report a novel chemical synergic interaction strategy to mitigate the abovementioned issues. A small amount of cationic β-cyclodextrin, composed of multiple ammonium cations, chlorine ions and abundant hydroxyl functional groups, was introduced into WBG perovskites, which effectively stabilized the halide ions and homogenized the phase distribution, comprehensively passivated the defects,and efficiently immobilized the Pb2+ ions. Encouragingly, the cationic β-cyclodextrin was universal and useful for different WBG perovskites, which favorably boosted the efficiencies by 10%-36% and extended the device operational stability to 2680 h. The integrated four-terminal orsix-terminal all-perovskite tandem solar cells exhibited efficiencies up to 24.39% and 22.42%, respectively. We demonstrated the cationic β-cyclodextrin-assisted internal chemical encapsulation effectively prevented the Pb leakage from severely damaged devices with only 5.63 ppb Pb leaching out. The target tandem solar cells with cationic β-cyclodextrin modification also realized a Pb sequestration efficiency of 93.4%.

Operando X-ray and Mass Spectroscopy of Reduced Graphene Oxide ( rGO )-Mediated Cobalt Catalysts for Boosting the Hydrogen Evolution Reaction

Inserting underlying reduced graphene oxide (rGO) into Co aims to regulate the chemical integrity and catalytic ability of the Co upper layer for hydrogen evolution reaction (HER) as a green-hydrogen goal. Principally, an mass spectrometer indicates 3.8 times more considerable hydrogen generation in Co/rGO than in Co. The spectroscopical approaches, combining soft and hard X-ray probing, illustrate the chemical oxidation evolution of electronic Co-3 and Co-4 states differently regarding the underlying rGO contribution. A unique examination is regarded as the phase transition from the initial middle to high oxidation and to deoxidation, related to the intermediate Co0 existence and H2 generation. The chemical adsorption of Co–O(H), Co–Hads, and H2 molecules desorption have been assigned their spectral significances. The rGO mediation indicates two significant metal Co and Co–O(H) blocks in the two-dimensional - domain. Density-functional-theory (DFT) calculation provides the regeneration, sustained stability, and decreasing energy barrier of Co–Hads catalysts due to the rGO incorporation, thereby augmenting the HER enhancement through the alternative Volmer-Heyrovsky process. The experiment, including mass spectrometer, soft, and hard X-ray, provides evidence regarding the catalyst’s HER enhancement. This study offers insights into the chemical composition, electronic structure, and active role of Co bonded with or without the extinct OH and H bonds, advancing our comprehension of electrocatalytic reactions, thus taking our knowledge of composite materials to stepwise electrocatalytic reactions forward. This cutting-edge experiment under environment and DFT studies gives critical information regarding the catalytic mechanism and chemical stability of the Co and rGO materials. Published by the American Physical Society 2024