Chemical Stability Research Articles

Thermodynamic stability, electronic structure and mechanical properties of Mo-Re binary alloys: A first-principles calculations

Using first-principles calculations, we have systematically studied thermodynamic stability, electronic structure and mechanical properties of Mo-Re binary alloys. The alloying element Re prefers to occupy the substitution position with a formation energy of 0.10 eV in Mo rather than the tetrahedron/octahedron interstitial position. The charge transfers are obviously present between Re and Mo atoms, which can be confirmed by the Bader charge analysis. The density of states (DOS) demonstrates that the d orbitals of Re and Mo atoms are hybridized, revealing that Re and its adjacent Mo atoms can form the directional bond containing covalent components. On the basis of above studies on the most stable occupancy structure, the mechanical quantities (the elastic constants Cij, bulk modulus B, Young’s modulus E, shear modulus G, Poisson’s ratio v, and B/G) have been analyzed for three Mo-Re alloys with the low Re content, which are Mo127Re1, Mo53Re1 and Mo15Re1, respectively. All these mechanical quantities of both Mo127Re1 and Mo53Re1 alloys are nearly the same as that of perfect Mo, while all these mechanical quantities of Mo15Re1 alloy are obviously larger or smaller than that of perfect Mo. This demonstrates that Mo15Re1 alloy has significantly different mechanical characteristics from Mo127Re1 and Mo53Re1 alloys as well as perfect Mo. These results can provide a significant reference for the application of Mo-Re alloys in future fusion fields.

Preparation, Physicochemical Characterization, and Stability Study of Lippia origanoides Essential Oil-Based Nanoemulsion as a Topical Delivery System.

Fungal diseases are a priority in research, development, and health care, according to the WHO, mainly due to Candida spp. Essential oils (EOs) of the genus Lippia have demonstrated broad antimicrobial biological activity. Previous studies identified the anti-Candida potential of a thymol/p-cymene chemotype EO from Lippia origanoides H.B.K coded "0018". Nanoemulsions favor the biological activity of EOs and overcome limitations such as low solubility, instability against oxidizing agents, pH, light, and low permeability. To develop, characterize, and adjust a prototype of an O/W nanoemulsion containing the "0018" EO from Lippia origanoides for its evaluation in an In vitro permeability study. Nanoemulsions were obtained using a high energy high shear method. Their particle size distribution, Z potential, viscosity, pH, encapsulation efficiency (EE), thermodynamic stability and the Turbiscan Stability Index (TSI) were evaluated. The nanoemulsion prototype was adjusted to improve performance characteristics and microbiological efficacy. Thymol was used as an analyte in the EO quantification using UHPLC-DAD. An O/W nanoemulsion with hydrodynamic diameter <200 nm and polydispersity index <0.3, EE >95%, with TSI < 1.5, anti-Candida albicans efficiency >95% was obtained; permeable with a flow of 6.0264 µg/cm2/h and permeability coefficient of 1.3170x10-3 cm/h. A pharmaceutical formulation prototype is obtained that maintains the physical and physicochemical characteristics over time. Permeability is verified in an in-vitro model. It is proposed to evaluate its antifungal activity in preclinical or clinical studies as a contribution to the treatment of topical fungal diseases caused by Candida spp., through the use of biological resources and Colombian biodiversity.

Development and analysis of the physical and electrochemical characteristics of a nano titanium (IV) tungstomolybdate supported on polyethersulfone composite cation exchange membrane

In this study, a series of novel composite membranes were synthesized utilizing polyethersulfone (PES), sulfonated polyethersulfone (SPES) as base polymer and titanium tungstomolybdate (TWM) as an inorganic ion exchange resin. The membranes were fabricated through the solution casting technique. The composite membranes exhibited enhanced thermal and chemical stability, as well as improved oxidative stability. All the composite membranes demonstrated higher hydrophilicity, with the SPES-TWM composite membranes displaying the lowest contact angle of 65°. The composite membranes also displayed favorable water uptake (up to 26% for SPES-TWM) and lower methanol uptake (maximum 12% for SPES-TWM) and better mechanical stability (maximum of 40 MPa for SPES-TWM). The SPES-TWM composite membranes exhibited the maximum ion exchange capacity of 1.32 meq.g−1. The transport number of 0.95 was obtained for SPES-TWM, which is comparable to the Nafion-117 membrane. The proton conductivity of both membranes increased as the temperature increased. The maximum proton conductivity of 6.3 mScm−1 was observed for SPES-TWM at 60 °C.

Curcumin-Enclosed Nanoparticles for Cancer Therapy

Abstract: Cancer is the greatest cause of mortality worldwide, and it is distinguished by the unrestrained proliferation of a group of aberrant cells, the random division of cells, and the invasiveness of genetically organized cells. At present, there are various strategies for curing of cancer-based on the type &amp; severity. In the earlier two decades, curcumin has received huge attention in pharmacological, biological, and nutraceutical research. In addition to triggering apoptosis in cancer cells, curcumin also inhibits cancer cell invasion and proliferation by stifling cellular signaling pathways. The lower water solubility of curcumin decreases the oral bioavailability, absorption into the systemic circulation, and chemical stability and finally bound the activity of curcumin as an anticancer agent. The pharmacology of curcumin, as well as its derivatives with relation to its anticancer potential, primary modes of action, &amp; cellular target, has been summarised in this article along with a list of the numerous curcumin enclosing nanoformulations. Multiple methods of administration have been developed for curcumin to boost its specificity. Encapsulation and other formulation processing techniques have been found to enhance both the solubility and bioavailability of curcumin. The nanoparticles' size, shape, surface characteristics, and targeting ligand are all factors that nanoformulation designers must think about when working to increase the efficacy and cellular targeting of anticancer treatments.

Two-dimensional MXene Nanomaterials: Preparation, Structure Modulation and the Applications in Electrochemical Energy Storage.

MXenes have attracted intensive attention owing to their unique twodimensional (2D) layered structure, high specific surface area, excellent conductivity, superior surface hydrophilicity, and chemical stability. In recent years, selective etching of the A element layers from MAX phases by fluorine-containing etchants (HF, LiF-HCl, etc) is a common method to prepare multilayered MXene nanomaterials (NMs) with plentiful surface terminations. At present, many studies have been reported on the use of fluorine-free etchants (NaOH, ZnCl2, etc) to etch MAX phases. The properties of MXene NMs are dependent on their structures. The purpose of this review is to focus on a comprehensive and systematical survey on the preparation, structure modulation, and applications of MXene NMs in electrochemical energy storage devices, including supercapacitors, lithium-ion battery, sodium-ion battery, potassium-ion battery, and aluminum-ion battery. Extensive information related to the preparation and applications of 2D MXene NMs for electrochemical energy storage and their associated patents were collected. This review highlights the recently reported 2D MXene NMs which are used in supercapacitor and various metal ion. It is found that the preparation methods have great impacts on the layer spacing and surface terminations of MXenes, consequently affecting their performance. Hence, this paper summarizes the research progress of the preparation strategies, layer spacing and surface termination modulation of MXene NMs. The applications of 2D MXene NMs in electrochemical energy storage are outlined. The forward-looking challenges and prospects for the development of MXenes are also proposed.

Investigating the chemical stability and thermal functionality of DMPT promoted TiO2 nanoparticles on unsaturated polyester resin

The incessant emergence of failures in mining roofs, along with escalating demands for high and sustainable roof support products such as resin anchor bolt capsules (resin), necessitates strengthening these elements. This study explores the transformative influence of Titanium oxide nanoparticles (TiO2) and its concentration on the chemical properties, stability, and thermal performance of polyester resin (UPE) nanocomposites. The investigation was carried out using Fourier-transform infrared (FTIR), Raman spectroscopy, and X-ray diffraction (XRD). Rheological behavior was assessed with a Brookfield viscometer, while thermal stability was examined via thermogravimetric analysis (TGA, DTG, and DTA). From the results obtained, the addition of nanoparticle TiO2 yielded a little significant change in the shift of the FTIR wavelength. However, substantial Raman peak disappearance from the peaks of the UPE neat compared to composites. The shift in Raman is associated with an increase in crystallinity due to TiO2 content. X-ray diffraction confirms the seamless presence of anatase TiO2 nanoparticles in the polyester resin matrix. The resin curing kinetics exhibit a 50-second reduction in the time to reach the exothermic peak when the nanomaterial content reaches 3% in TiO2. An increase in nanomaterial content leads to a shorter time to peak at a higher exothermic temperature, indicating improved resin cure rates. This study substantiates enhanced chemical and thermal stabilities with increasing nanomaterial content, affirming the positive impact of nanomaterial infusion on resin resilience and stability.

Field demonstration of a 10 MW CO2 capture pilot plant in extended operation using KoSol absorbents for treating off-gas in a coal fired power plant

Efficient CO2 absorbents are crucial for reducing energy use in CO2 capture absorption process. This study evaluates the performance of amine-based CO2 absorbents, KoSol-5 and KoSol-6, developed by the Korea Electric Power Corporation. In a 10 MW pilot plant, KoSol-6 was found to capture more than 90% of the daily CO2 emissions, amounting to over 180 tons per day, from the exhaust gasses of a coal-fired power plant. Its regeneration energy (Qregen) was 2.42 GJ/ton CO2 in the standard absorption process, which is 39.2% less than the monoethanolamine (MEA) system. Implementing advanced techniques like intercooling, lean vapor compression, and thermal vapor recompression further optimized this process. Among these, the thermal vapor recompression mode turned out to be the most efficient and stable. In addition, KoSol-6 showcased excellent thermal and chemical stability, with a consistent Qregen of 2.34 GJ/ton CO2 over a 10,000-hour test. The study provides insights into the potential of KoSol-5 and KoSol-6 for large-scale applications and further developments in CO2 capture technology.

Significantly improving the thermal stability of alginate lyase AlyC3 from Psychromonas sp. C-3 by computational redesign

Alginate lyase is a key enzyme in the bioproduction of alginate oligosaccharides. The alginate lyase AlyC3, derived from Psychromonas sp. C-3, can hydrolyze homopolymerized mannuronic acid into oligosaccharides (primarily composed of mannuronate trimer), which possess physiological properties such as bacteriostatic and antioxidant activities and show a better application prospect. However, the poor thermal stability hinders its potential application in industrial production. In this study, AlyC3 mutants A35P, L95F, N138Y and M162I were obtained through the protein repair one-stop shop (PROSS) design combined with protein data bank in Europe (proteins, interfaces, structures and assemblies) (PDBePISA) analysis of the dimer interface. The results demonstrated that the thermodynamic and kinetic stability of these single-point mutants were significantly improved compared to the wild-type (WT), with the melting temperature increased by 4.33, 9.35, 9.74 and 11.24 °C, respectively, while the half-life (t1/2) was 1.66, 1.02, 1.02 and 1.53 times higher than that of WT, respectively. Based on this, the beneficial mutations were further combined to obtain a combinatorial mutant, A35P-L95F–N138Y-M162I, which exhibited the superior thermal stability. Notably, the combinatorial mutant's melting and optimal temperature increased by 17.05 and 10 °C, respectively; moreover, the mutant enzyme's t1/2 and enzyme activity were 8.21 times and 123.93% higher than those of the WT, respectively. Structural analyses indicated that increased hydrophobic interactions and polar bonding between the mutated and nearby residues, with improved rigidity in the flexible loop, might account for the significantly improved thermal stability of the reengineered AlyC3, which makes it a robust candidate for alginate oligosaccharide production.

Flexible silver nanoparticle@aramid nanofiber SERS substrates fabricated by radio frequency magnetron sputtering for rapid detection of toxic substances

Aramid nanofibers (ANFs) have gained great interest as promising polymer substrates for various applications because of their exceptional mechanical properties, high aspect ratio, large specific surface area and excellent chemical and thermal stability. However, the use of ANFs as nano-sized functional substrates for surface-enhanced Raman scattering (SERS) sensing applications has been scarcely reported. In this research, ANF membranes fabricated by vacuum-filtration are served as SERS matrix materials. The silver nanoparticle-coated ANF (AgNP@ANF) membranes are fabricated by a facile, cost-effective, environmental-friendly, and scalable magnetron sputtering technique. Different sputtering times from 15 to 120s have been studied for AgNP@ANF substrates in terms of their SERS performance. The optimal AgNP-90@ANF SERS substrate exhibits good detection sensitivity of 10-10M for malachite green (MG), high enhancement factor of 7.7×108 and prominent signal reproducibility (RSD=5.87%), as well as impressive storage stability. Furthermore, the AgNP@ANF SERS substrates also demonstrated excellent detection capability for methylene blue and crystal violet, with sensitivities of 10-10 and 10-9M, respectively. Besides, the flexible AgNP@ANF SERS substrate can also be used to rapidly detect pesticide residues on uneven surfaces through a facile paste-and-read treatment. The simple-to-manufacture, inexpensive, scalable, and sensitive AgNPs@ANF sensors are very promising for commercial SERS applications in the future.

Exploring Rare-Earth compound ErMn2Si2 for thermoelectric and photoelectrochemical applications using Density functional theory

The physical and magnetic properties of the ErMn2Si2 compound are investigated with PDE and RPBE functions using the generalized gradient approximations (GGA) approach within the ferromagnetic phase. The obtained structural optimization results carried out using general gradient approximation (GGA) applying Perdew-Burke-Ernzerhof (PBE), which were consistent with the previously experimental findings. The result shows that the ferromagnetic phase of ErMn2Si2 exhibits the highest thermodynamic stability. Furthermore, the electronic band structure analysis within the ferromagnetic phase indicates the metallic behaviour of the compound in both spin channels. A hybridization between Er-f and Mn-d states is observed in the valence band along with the Si-p state in the conduction band. Total magnetic moments confirm the ferromagnetic characteristics of the ternary inter-metallic ErMn2Si2 compound. In this study, analysis of the Seebeck coefficient was discussed in detail. The electrical and thermal conductivities of the compound were investigated in a broad range of temperatures (0 to 600 K). Additionally, we present the quasi-harmonic model-calculated thermodynamic characteristics as a function of pressure (0–60 GPa) and temperature (0–1200 K). Evaluating the optical characteristics, ErMn2Si2 shows strong dielectricmaterial characteristics in the visible regions of the electromagnetic spectrum. Further, the figure of merit (ZT) was probed. The enhanced ZT values of ErMn2Si2 compounds at elevated temperatures make it a potential candidate for high-temperature applications especially for thermoelectric devices. These results may be useful for further investigations of the rear-earth substituted ErMn2Si2-based compounds for various applications.

Covalent organic framework membranes reconstructed pore channels through metal-phenolic complexation for dye/salt separation

Covalent organic frameworks (COFs) characterized by high porosity, ordered channels, and remarkable chemical stability are potential candidates for the fabrication of nanofiltration separation membranes. In general, COFs membranes, generated through the process of interfacial polymerization, exhibit superior permeance without comparatively poor selectivity toward small molecules. Hereby, it was addressed with a simplified route to construct an extra selective layer on the COFs membranes. Concretely, COFs (TpPa/HPAN) membranes were first fabricated via interfacial polymerization on the hydrolyzed polyacrylonitrile (HPAN) membranes by utilizing monomers of 1,3,5-triformylphloroglucinol (Tp) and p-phenylenediamine (Pa). Then, a selective layer of metal-phenolic complex was constructed on the TpPa/HPAN membranes by electrostatic adsorption and metal-phenolic complexation. The introduction of a metal-phenolic complex selective layer masked the intrinsic pore size of TpPa and enhanced the hydrophilicity and electronegativity of the membrane, which improved the rejection property of the membranes for dyes larger than 350 Da. The fabricated M-TpPa/HPAN membranes showed exceptional performance in dye desalination with a water permeance of 92.1 L‧m-2‧h-1‧bar-1, rejections of Congo red and Eriochrome black T (EBT) over 99%, 78.6% of acid fuchsin rejection, 85.3% of acid orange 7 rejection, low rejection of salts (e.g., 6.2% for NaCl rejection), and the NaCl/EBT separation factor up to 243. Additionally, the M-TpPa/HPAN membranes maintained excellent stability during long-term filtration. The strategy of building an extra selection layer with eco-friendly, cost-effective, and scaled-up methods is also extensible for the other COFs and framework-based membranes.

Computational Insight into the Mechanism of Action of DNA Gyrase Inhibitors; Revealing a New Mechanism.

Discovery of novel antimicrobial agents is in need to deal with antibiotic resistance. Elucidating the mechanism of action for established drugs contributes to this endeavor. DNA gyrase is a therapeutic target used in the design and development of new antibacterial agents. Selective antibacterial gyrase inhibitors are available; however, resistance development against them is a big challenge. Hence, novel gyrase inhibitors with novel mechanisms are required. In this study, the mechanism of action for selected DNA gyrase inhibitors available was carried out through molecular docking and molecular dynamics (MD) simulation. In addition, pharmacophore analysis, density functional theory (DFT) calculations, and computational pharmacokinetics analysis of the gyrase inhibitors were performed. This study demonstrated that all the DNA gyrase inhibitors investigated, except compound 14, exhibit their activity by inhibiting gyrase B at a binding pocket. The interaction of the inhibitors at Lys103 was found to be essential for the binding. The molecular docking and MD simulation results revealed that compound 14 could act by inhibiting gyrase A. A pharmacophore model that consisted of the features that would help the inhibition effect was generated. The DFT analysis demonstrated 14 had relatively high chemical stability. Computational pharmacokinetics analysis revealed that most of the explored inhibitors were estimated to have good drug-like properties. Furthermore, most of the inhibitors were found to be non-mutagenic. In this study, mode of action elucidation through molecular docking and MD simulation, pharmacophore model generation, pharmacokinetic property prediction, and DFT study for selected DNA gyrase inhibitors were carried out. The outcomes of this study are anticipated to contribute to the design of novel gyrase inhibitors.

A europium-based MOF fluorescent probe for efficiently detecting Co2+ and CrO42−

Cobalt is an essential trace element in the human body that is vital for metabolism in living organisms. Insufficient or excessive intake of cobalt can lead to adverse effects. We prepared a europium-based metal–organic framework (Eu-MOF), NH4[Eu(sal)4(phen)2] (abbreviated as Eu-sal, sal = salicylic acid group, phen = 1,10-phenanthroline). Fluorescence investigations revealed that Eu-sal can efficiently and selectively identify Co2+ through a fluorescence quenching effect, with a quenching efficiency K SV and limit of detection (LOD) of 2.7 × 104 M−1 and 0.37 μM, respectively. In addition, Eu-sal also shows highly selective for CrO42− (K SV: 3.6 × 104 M−1; LOD: 0.27 μM). The quenching of Eu-sal fluorescence emission by Co2+ and CrO42− ions may be caused by spectral overlap, energy transfer, and competition. Furthermore, Eu-sal has good thermal and chemical stability. These results indicate that Eu-sal is a promising fluorescence probe for highly selective detection of Co2+ and CrO42− ions.

Capacitive and Efficient Near-Infrared Stimulation of Neurons via an Ultrathin AgBiS2 Nanocrystal Layer.

Colloidal nanocrystals (NCs) exhibit significant potential for photovoltaic bioelectronic interfaces because of their solution processability, tunable energy levels, and inorganic nature, lending them chemical stability. Silver bismuth sulfide (AgBiS2) NCs, free from toxic heavy-metal elements (e.g., Cd, Hg, and Pb), particularly offer an exceptional absorption coefficient exceeding 105 cm-1 in the near-infrared (NIR), surpassing many of their inorganic counterparts. Here, we integrated an ultrathin (24 nm) AgBiS2 NC layer into a water-stable photovoltaic bioelectronic device architecture that showed a high capacitive photocurrent of 2.3 mA·cm-2 in artificial cerebrospinal fluid (aCSF) and ionic charges over 10 μC·cm-2 at a low NIR intensity of 0.5 mW·mm-2. The device without encapsulation showed a halftime of 12.5 years under passive accelerated aging test and did not show any toxicity on neurons. Furthermore, patch-clamp electrophysiology on primary hippocampal neurons under whole-cell configuration revealed that the device elicited neuron firing at intensity levels more than an order of magnitude below the established ocular safety limits. These findings point to the potential of AgBiS2 NCs for photovoltaic retinal prostheses.

Real-time and highly responsive hydrogen mapping in pure Fe using TiO2 thin films

A hydrogen visualization method with high responsivity and chemical stability under atmospheric corrosion is necessary to inhibit hydrogen embrittlement, which can occur with hydrogen uptake of structural materials. In this study, a highly responsive hydrogen mapping technique for steels was successfully established using a TiO2 thin film and Pd intermediate layer. The color of the TiO2 film on the hydrogen-detection side changes during hydrogen charging on the hydrogen-entry side of the Fe specimen, indicating that the color changes were attributed to the hydrogen uptake of the Fe surface and subsequent introduction of hydrogen atoms to the TiO2 film. Considering the responsivity and visibility, the optimal thickness of the TiO2 film was determined to be 20 nm. As TiO2 is a chemically stable material, the proposed mapping technique can be used to monitor the hydrogen absorbed into metallic materials under outdoor conditions.

Development of Sustainable 3D Printable Ternary Composite

3D printing technology has the potential to reduce construction waste through its controlled manufacturing process and optimized material consumption, making it a promising sustainable construction approach with reduced environmental impact. However, current 3D printed structures often have a high carbon footprint due to the large amounts of fine-grained primary materials used in mortar composites. Most efforts to develop 3D printed structures are associated with concrete and Portland cement-based materials.This research presents an innovative approach for the reuse of gypsum to develop a material suitable for 3D printing, with the goal to industrialize the usage of waste gypsum in civil engineering. The objective of this study is to develop a sustainable gypsum-cement-pozzolanic (GCP) ternary binder composite, incorporating recycled industrial waste gypsum materials such as construction demolition waste gypsum (CDG), along with Portland cement and secondary pozzolanic materials. The GCP ternary composite combines the desired properties of gypsum, such as fast setting time, with those of Portland cement, which offers high final strength. The addition of a pozzolanic component is essential to ensure the chemical stability of this ternary system.As part of this study, ternary composites were designed and tested for their mechanical properties, durability, and suitability for 3D printing. Development and optimization of the ternary composite was carried out as a loop of procedures (Fig.1). Through these optimization procedures, a range of mixtures with necessary properties for 3D printing was found. To ensure sustainability and to assess the environmental impact of the mixtures, life cycle assessment (LCA) was performed.The LCA of GCP composites showed at least 1.5 times lower embodied energy and carbon dioxide emissions compared to Portland cement-based mortars. This is without considering avoided emissions from the end-of-life stage of gypsum waste, as well as higher technical properties that make GCP composites superior to regular cement composites. Considering these factors, GCP composites exhibit even lower emissions and are considered a viable alternative to Portland cement-based mortars.

Effect of the spin-orbit coupling and Hubbard corrections in predicting the electronic and magnetic properties of vacancy-ordered double perovskites A2WCl6 (A = Rb and Cs)

The structural, elastic, electronic, and magnetic properties of the vacancy ordered double perovskite compounds A2WCl6 (A = Rb, Cs) have been investigated within the full-potential linearized augmented plane waves (FP-LAPW) method. The structural properties in the cubic phase were examined and are consistent with the available experimental results. The materials are more stable in the ferromagnetic phase. The mechanical, dynamical and the thermodynamical stability have also been verified. The electronic and magnetic properties were first calculated by GGA-WC approximation, the studied materials are found to be half-metallic. Including Hubbard correction (U), the W-d states move towards higher energy enlarging the band gap in the spin-down channel. The spin–orbit coupling (SOC) was added to GGA-WC+U which reveal that these compounds behave as semiconductors in both spin channels. The density of states showed that the valence band is mainly characterized by the W-d together with Cl-p states while the conduction band is dominated by W-d and (Cs/Rb)-d states. The calculated properties present semiconducting ferromagnetic nature that is considered as necessary factor in spintronics applications.

Thermodynamic stability and vibrational properties of multi-alkali antimonides

Abstract Modern advances in generating ultrabright electron beams have unlocked unprecedented experimental advances based on synchrotron radiation. Current challenges lie in improving the quality of electron sources with novel photocathode materials such as alkali-based semiconductors. To unleash their potential, a detailed characterization and prediction of their fundamental properties is essential. In this work, we employ density functional theory combined with machine learning techniques integrated into the hiphive package to probe the thermodynamic stability of various alkali antimonide crystals, emphasizing the role of the approximations taken for the exchange-correlation potential. Our results reveal that the SCAN functional offers an optimal trade-off between accuracy and computational costs to describe the vibrational properties of these materials. Furthermore, it is found that systems with a higher concentration of Cs atoms exhibit enhanced anharmonicities, which are accurately predicted and characterized with the employed methodology.

Efficient and Durable Oxidation Removal of Formaldehyde over Layered Double Hydroxide Catalysts at Room Temperature.

Room temperature catalytic oxidation (RTCO) using non-noble metals has emerged as a highly promising technique for removal of formaldehyde (HCHO) under ambient conditions; however, non-noble catalysts still face the challenges related to poor water resistance and low stability under harsh conditions. In this study, we synthesized a series of layered double hydroxides (LDHs) incorporating various dual metals (MgAl, ZnAl, NiAl, NiFe, and NiTi) for formaldehyde oxidation at ambient temperature. Among the synthesized catalysts, the NiTi-LDH catalyst showed an HCHO removal efficiency and CO2 yield close to 100.0%, and exceptional water resistance and chemical stability on running 1300 min. The abundant hydroxyl groups in LDHs directly bonded with HCHO, leading to the production of CO2 and H2O, thus inhibiting the formation of CO, even in the absence of O2 and H2O. The coexistence of O2 effectively reduced the reaction barrier for H2O molecule dissociation, facilitating the formation of hydroxyl groups and their subsequent backfill on the catalyst surface. The mechanisms underlying the involvement and regeneration of hydroxyl groups in room temperature oxidation of formaldehyde were elucidated with the combined in situ DRIFTS, HCHO-TPD-MS, and DFT calculations. This work not only demonstrates the potential of LDH catalysts in environmental applications but also advances the understanding of the fundamental processes involved in room temperature oxidation of formaldehyde.

2D Zn (II) Metal‐Organic Framework as a Highly Sensitive Luminescent Sensor for Detection of the Cr2O72− and Fe3+

AbstractIn this work, NH2‐containing organic ligand 5‐Aminoisophthalic acid (AIPA), and trans‐1,2‐bis(4‐pyridyl)ethene (bpe) were selected as organic ligands to construct a new two‐dimensional luminescent Zn(II) metal‐organic framework [Zn(AIPA)(bpe)1/2]⋅named MOF‐1. It is worth noting that MOF‐1 exhibited excellent thermal stability and chemical stability in common solvents and different pH aqueous solution. As we expected, the luminescence sensing investigations demonstrated that MOF‐1 could be deemed as a multifunctional fluorescence sensor toward Cr2O72− and Fe3+ via a “turn‐off” effect. Notably, MOF‐1 had high selectivity and sensitivity for Fe3+ and Cr2O72− with low detection limits of 9.72×10−5 M and 1.95×10−5 M, respectively. Furthermore, the possible quenching mechanisms were also explored in detail.