Marital dissolution in midlife represents a significant life transition with profound implications for cognitive health. As divorce rates among adults aged 50 and older have more than doubled since the 1990s, this phenomenon—commonly referred to as “gray divorce”—has reshaped the landscape of midlife relationships. Unlike historical patterns where widowhood was the primary cause of marital disruption, today’s midlife transitions are increasingly driven by divorce. This shift underscores the need to examine how such transitions affect cognitive well-being, particularly given that mild cognitive impairment (MCI) affects roughly 12% of adults aged 55–69 and is a strong predictor of future dementia. Using longitudinal data from the Health and Retirement Study (1998–2016), this study investigates the impact of divorce and widowhood on the onset of MCI among men and women aged 50–65, while also assessing whether repartnering mitigates these risks.

The stress model provides a theoretical framework for understanding these associations. According to this model, the loss of a spouse through either divorce or widowhood triggers a cascade of adverse effects, including diminished economic stability, reduced social support, and psychological distress—all of which may contribute to cognitive decline. The findings reveal that midlife widowers face a significantly elevated risk of MCI, with nearly 27% developing mild cognitive impairment by age 65. In contrast, divorced men show lower but still notable risks, while women who experience either divorce or widowhood initially exhibit higher odds of cognitive impairment. However, once economic, social, and psychological resources are accounted for, these differences largely dissipate, suggesting that resource loss mediates much of the observed risk.SLFN11 Antibody In stock Notably, individuals who repartner after marital dissolution do not differ significantly from those who remain continuously married in their likelihood of developing MCI, indicating that reestablishing a partnership can buffer against cognitive decline.IFITM2 Antibody Autophagy

These results highlight the importance of considering dynamic life transitions rather than static marital status when assessing long-term health outcomes. While both divorce and widowhood are stressful events, their cognitive consequences vary by gender and context.PMID:35227759 Men, particularly widowers, appear especially vulnerable, likely due to fewer social ties outside marriage and greater reliance on partners for emotional and practical support. Repartnering offers a protective effect, reinforcing the value of stable, supportive relationships in maintaining cognitive reserve. These insights carry important implications for public health policy and clinical practice: interventions aimed at supporting midlife adults experiencing marital dissolution—especially widowed men—should prioritize enhancing economic security, expanding social networks, and promoting mental health. Given the rising diversity of post-marital partnerships, future research must continue to explore how evolving relationship patterns shape cognitive aging across the lifespan.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com

In this study, a novel colorimetric aptasensor was developed for the rapid and visual detection of human papillomavirus type 16 (HPV16) L1 proteins using gold nanoparticles (AuNPs) and an RNA aptamer specifically targeting HPV16 L1 protein (APTHPV16 L1). The method relies on salt-induced aggregation of AuNP-APTHPV16 L1 conjugates in the presence of HPV16 L1 proteins at trace levels (ppb). Upon addition of salt, the conjugates aggregate due to specific binding between APTHPV16 L1 and HPV16 L1, resulting in a distinct color change from red to blue. This shift is attributed to a significant alteration in surface plasmon resonance (SPR) absorption peaks of AuNPs, which move toward shorter wavelengths. The relative absorbance ratio (Ablank – Asample)/Ablank at 520 nm demonstrated a stable and linear response across a concentration range of 9.6 to 201.6 ng mL⁻¹, indicating high sensitivity and reproducibility. The visual detection limit was determined to be as low as 9.6 ng mL⁻¹, enabling naked-eye identification of target proteins without complex instrumentation.

The proposed aptasensor exhibited excellent selectivity against structurally similar proteins, including HPV6 L1 and HPV18 L1, confirming minimal cross-reactivity. This specificity arises from the high-affinity interaction between APTHPV16 L1 and HPV16 L1 (KD = 0.05 pM), which triggers conformational changes leading to aptamer detachment and subsequent nanoparticle aggregation. The assay was validated through extensive characterization using UV-Vis spectroscopy, zeta potential measurements, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). These analyses confirmed that AuNPs remained dispersed when bound to APTHPV16 L1 but aggregated upon exposure to HPV16 L1 proteins under high-salt conditions.

The practical applicability of the sensor was further demonstrated by its successful use in detecting HPV16 L1 proteins in both clinical samples and vaccine formulations. Results obtained from real sample testing were consistent with those from enzyme-linked immunosorbent assay (ELISA), a gold-standard method, thereby verifying the accuracy and reliability of the colorimetric approach. Recovery rates ranged from 74.8% to 85.4%, with acceptable relative standard deviations (RSDs) between 1.STAT5B Antibody Purity 5% and 2.838818-26-1 Biological Activity 8%, confirming robust performance in complex matrices.PMID:34278583 Additionally, the AuNP-APTHPV16 L1 conjugates showed excellent stability over 48 hours, ensuring reagent shelf-life and operational convenience.

This work presents a simple, cost-effective, sensitive, and selective platform for the rapid screening and quantitative analysis of HPV16 L1 proteins. Its visual readout capability makes it highly suitable for point-of-care diagnostics, especially in resource-limited settings. By combining the advantages of aptamer specificity and AuNP-based optical signaling, the proposed aptasensor offers a promising alternative to conventional immunoassays and mass spectrometry-based methods. It holds strong potential for improving early detection of cervical cancer risk, monitoring vaccine efficacy, and enhancing personalized clinical management of HPV-related diseases.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com

Tin sulfide (SnS2) nanoparticles have emerged as promising materials for visible-light-driven photocatalysis due to their suitable bandgap energy (~2.2–2.3 eV), chemical stability in aqueous environments, and ability to degrade organic pollutants. In this study, we systematically investigated the influence of sulfur precursor type—thioacetamide (TAA) versus thiourea (TU)—and the addition of citric acid (CA) as a capping agent on the structural, morphological, and photocatalytic properties of hydrothermally synthesized SnS2 nanoparticles. The results revealed that TAA leads to significantly smaller nanoparticles with an average size of 24.0 nm compared to 616 nm when TU is used. Transmission electron microscopy (TEM) confirmed that TAA-derived samples predominantly formed hexagonal nanoplatelets, while TU-based samples exhibited larger, irregularly shaped particles. The presence of citric acid during synthesis suppressed the formation of hexagonal structures, promoting disc-shaped morphologies instead, which negatively impacted photocatalytic efficiency.

X-ray diffraction (XRD) analysis confirmed the dominant phase as hexagonal SnS2 (JCPDS 23-0677), with minor SnO2 impurities (<10%) attributed to local pH fluctuations during hydrothermal treatment. BET surface area measurements showed higher values for TAA-based samples (117.1 m²/g) than those from TU (87.2 m²/g), correlating with smaller particle size and enhanced surface reactivity. Fourier-transform infrared spectroscopy (FTIR) verified the successful incorporation of citric acid only in CA-containing samples, with characteristic C=O stretching at 1734 cm⁻¹, indicating coordination with SnS2 surfaces. However, this interaction reduced photocatalytic activity, likely due to site blocking and hindered charge transfer. Photocatalytic degradation of methyl orange (MO) under visible light demonstrated superior performance for TAA-synthesized SnS2, achieving 98% degradation within 1.5 hours—significantly faster than TU-based samples (30% degradation in the same time). The apparent rate constant (kapp) for S(TAA) was 0.029 min⁻¹, outperforming TiO2 P25 (kapp = 0.0102 min⁻¹). Kinetic analysis indicated that SnS2 primarily degrades MO via direct reduction of the azo bond (–N=N–), resulting in partial mineralization with sulfanilic acid identified as the main transformation product. Notably, no further oxidation of byproducts occurred, suggesting limited oxidative capability. Recyclability tests over three cycles showed gradual performance decline, especially for S(TAA), linked to structural degradation and increased SnO2 content post-cycling, confirmed by XRD.53-86-1 web

Further evaluation revealed that SnS2 nanoparticles failed to degrade atrazine and imazapic, both containing stable C–N bonds.RBBP5 Antibody manufacturer However, metribuzin—a herbicide with a labile N–N bond—underwent transformation into a unique product (P2), distinct from those formed via photolysis alone, indicating a catalytic role for SnS2 beyond simple photoexcitation.PMID:35151072 These findings highlight the selective nature of SnS2 photocatalysis, particularly effective for azo bond cleavage but ineffective against other functional groups. Thus, SnS2 shows promise as a targeted catalyst for specific pollutant classes rather than a broad-spectrum photocatalyst. Future work should focus on designing heterostructured systems combining SnS2 with materials capable of generating reactive oxygen species to achieve complete mineralization.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com

A series of thermal rearrangement (TR) copolymer membranes were developed through the copolymerization of 9,9-bis(3-amino-4-hydroxyphenoxyphenyl) fluorene (BAHPPF), 9,9-bis(3-amino-4-hydroxyphenyl)fluorene (BAHPF), and 2,2′-bis(3,4′-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA), followed by thermal imidization and subsequent thermal rearrangement. The influence of the molar ratio of diamines on the structure and performance of these copolymer membranes was systematically investigated. Notably, the copolymer precursors CP-4:6 and CP-5:5 exhibited outstanding mechanical properties. While the mechanical strength of the precursor membranes declined rapidly with increasing thermal treatment temperature, TRCP-4:6 retained a tensile strength of 21.2 MPa after exposure to 450 °C. Generally, gas permeabilities of TR copolymers increased with higher BAHPF content.NR1I3 Antibody In stock Among the tested samples, TRCP-3:7 and TRCP-4:6 demonstrated superior gas permeability combined with high O₂/N₂ and CO₂/CH₄ selectivities.Transferrin Antibody Purity & Documentation Specifically, TRCP-4:6 achieved H₂, CO₂, O₂, N₂, and CH₄ permeabilities of 244.4, 269.0, 46.8, 5.20, and 4.60 Barrers, respectively, with CO₂/CH₄ and O₂/N₂ selectivities reaching 58.48 and 9.00—both exceeding the 2008 upper bound for gas separation performance. These results indicate that the fluorene-based TR copolymers are promising candidates for advanced membrane materials in gas separation applications.

The study highlights the potential of incorporating rigid fluorene units into thermally rearranged polymers to enhance both gas transport and mechanical integrity. The presence of bulky fluorene groups effectively disrupts chain packing, increases free volume, and improves molecular rigidity, which are critical factors in achieving high permeability without sacrificing selectivity. Moreover, the copolymerization strategy enables fine-tuning of the chemical architecture, allowing optimization of both physical and separation properties. The successful balance between enhanced permeability and maintained mechanical robustness underscores the feasibility of these materials for practical deployment in industrial gas separation processes such as CO₂ capture from natural gas streams or hydrogen purification.PMID:35230092 This work provides a clear pathway toward next-generation polymer membranes that overcome the traditional trade-off between permeability and selectivity, paving the way for more efficient and sustainable separation technologies.

The structural evolution during thermal rearrangement was confirmed via FTIR, XPS, and XRD analyses, showing the formation of benzoxazole rings and an increase in interchain spacing due to CO₂ release. The amorphous nature of the resulting membranes, coupled with a significant increase in d-spacing—reaching up to 0.60 nm in TRCP-4:6—supports the development of effective microporous networks favorable for selective gas diffusion. Additionally, DSC and DMA data revealed glass transition temperatures around 350 °C, indicating excellent thermal stability suitable for demanding operational environments. Overall, this research demonstrates that fluorene-containing TR copolymers offer a unique combination of high gas permeability, exceptional selectivity, and sufficient mechanical durability, making them strong contenders for future membrane-based gas separation systems.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com

The integration of differential mobility spectrometry (DMS) with multidimensional liquid chromatography–mass spectrometry (LCxDMS-MS) has emerged as a powerful analytical platform for the separation and identification of complex mixtures. A key challenge in this approach lies in balancing selectivity, resolution, and sensitivity—factors that are heavily influenced by the choice and concentration of gas-phase modifiers. This study investigates the use of binary modifier mixtures, combining nonclustering solvents such as cyclohexane (Ch), n-hexane, or n-octane with clustering modifiers like isopropanol (IPA) or ethanol (EtOH), to achieve fine-tuned control over DMS performance. By replacing the conventional single-channel pump with a binary high-performance liquid chromatography (HPLC) pump, the system enables precise delivery of modifier mixtures at constant flow rates under both isocratic and gradient modes. This setup allows for real-time modulation of modifier composition, offering enhanced flexibility in tuning the compensation voltage (CoV) window and optimizing separation conditions.

For 85 analytes spanning diverse physicochemical properties, the impact of varying modifier ratios was systematically evaluated. The results demonstrate that cyclohexane exhibits minimal CoV shifts (|ΔCoV| < 4 V) compared to pure nitrogen, indicating its potential as a nonclustering modifier. Density functional theory (DFT) calculations further support this behavior, showing positive Gibbs free energy (G) values for ion–cyclohexane cluster formation, which implies thermodynamic instability of such clusters. In contrast, even low concentrations of IPA (0.1%) in cyclohexane induce significant negative CoV shifts—up to 50 V—for molecules with molecular weights below 400 Da, highlighting its strong clustering capability. These findings reveal distinct ion separation mechanisms depending on modifier ratios: nonclustering modifiers preserve baseline ion mobility characteristics, while clustering modifiers actively modulate ion dynamics through dynamic clustering and declustering processes. Importantly, small changes in clustering modifier concentration dramatically affect the separation of positional isomers and diastereoisomers. For example, sulfonamide isomers I, II, and III exhibited sequential CoV shifts and multiple “points of selectivity inversion” as IPA concentration increased from 0 to 2.1%, enabling reordering of peak elution order and enhancing orthogonality. Similarly, (+)-ephedrine and (+)-pseudoephedrine showed maximum separation at ~0.5% ethanol, followed by a decline at higher concentrations due to saturation effects. The CoV shifts displayed linear dependence on the natural logarithm of the modifier/nitrogen mole ratio, suggesting first-order kinetics in dynamic clustering/declustering.BDH2 Antibody supplier This kinetic model underscores the importance of interaction potentials and cluster binding energies in determining DMS resolution.

Furthermore, the study reveals critical trade-offs between sensitivity and modifier concentration. While 1.5% IPA significantly reduced overall MS signal intensity (-55%), 0.Kif 7 Antibody Formula 1% IPA in cyclohexane yielded superior sensitivity with only -26% loss.PMID:33958010 Notably, certain compounds like quinidine showed improved response with increasing IPA, whereas caffeine experienced near-complete signal suppression. These variations are attributed to charge stripping, analyte fragmentation due to high effective temperature (Teff), and competition for protons in the electrospray plume. The ability to rapidly switch between modifier compositions using a gradient-capable HPLC pump offers a practical solution for maintaining sensitivity while expanding separation power.

In conclusion, binary modifier mixtures provide a versatile strategy for optimizing DMS parameters in LCxDMS-MS workflows. They enable dynamic control of CoV windows, reduce MS cycle times by narrowing scanning ranges (from 70 V to 55 V), and enhance selectivity without compromising robustness. The use of nonclustering modifiers like cyclohexane facilitates quick equilibration and stable CoV reproducibility, making them ideal for rapid method development. This approach not only improves analytical performance but also serves as a viable alternative to traditional multidimensional LCxLC separations, particularly when fast, high-resolution analysis is required.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com

Lead halide perovskites have emerged as high-performance optoelectronic materials over the past decade, achieving remarkable success in solar cells, light-emitting diodes, and photodetectors. Their exceptional properties stem from the Pb²⁺ cation with a lone-pair 6s² electronic configuration embedded in a mixed covalent-ionic lattice. However, concerns regarding lead toxicity and material instability hinder their large-scale commercialization. This review focuses on alternative Pb-free semiconductors containing lone-pair ns² cations—such as Sn²⁺, Ge²⁺, Sb³⁺, Bi³⁺, and Te⁴⁺—which offer promising pathways toward sustainable and efficient optoelectronics. We begin by elucidating the physical origin of superior optoelectronic behavior arising from the ns² configuration: dispersive band edges enable balanced carrier transport, p–p orbital transitions enhance light absorption and emission, antibonding states at valence band maxima promote defect tolerance, cross-bandgap hybridization leads to strong dielectric screening, and Rashba spin-splitting reduces recombination rates. These intrinsic features collectively contribute to long carrier diffusion lengths and high photoluminescence quantum yields.

We then systematically categorize these materials by structural dimensionality—ranging from three-dimensional (3D) perovskites to zero-dimensional (0D) clusters—highlighting how dimensionality governs electronic structure, carrier dynamics, and device performance. In 3D systems like tin-based perovskites (FASnI₃), tunable bandgaps (~1.4 eV) and high mobility make them viable for photovoltaics, though oxidation of Sn²⁺ remains a critical challenge. Double perovskites such as Cs₂AgBiBr₆ exhibit indirect bandgaps but demonstrate excellent X-ray detection capabilities due to high resistivity and favorable µτ products. Two-dimensional (2D) materials, including layered bismuth iodides (BiI₃), antimony/bismuth chalcogenides (Sb₂Se₃, Bi₂Se₃), and indium selenide (InSe), display strong anisotropy and tunable bandgaps via layer thickness control, enabling high responsivity in photodetectors.SCG2 Antibody Epigenetics The unique topological nature of Bi₂Se₃ enhances surface carrier transmission, while its helical states suppress backscattering, leading to ultrafast response times. In one-dimensional (1D) systems like Sb₂S₃ ribbons, carrier transport is highly directional, offering potential for low-dimensional electronics despite challenges related to deep-level defects.AMY1A Antibody Purity & Documentation Zero-dimensional (0D) A₃M₂X₉ perovskites (e.g., Cs₃Bi₂I₉) exhibit strong excitonic effects and high stability, making them suitable for radiation detection, although their indirect bandgaps limit photovoltaic efficiency.

Recent advances in synthetic strategies—including two-step deposition, additive engineering with SnF₂ or hydrazine derivatives, defect passivation via organic ligands, and interface engineering with tailored charge transport layers—have significantly improved film quality and device performance across all dimensionalities.PMID:34997456 For example, incorporating phenylhydrazine hydrochloride into FASnI₃ precursors increases carrier lifetime from 7.6 to 25.6 ns, boosting solar cell efficiency to 11.4%. Similarly, using indene-C60 bisadduct (ICBA) as an electron transport layer in PEAxFA₁₋ₓSnI₃ devices enables record efficiencies of 12.4% with enhanced stability. Despite progress, persistent issues remain: facile oxidation of Sn²⁺ and Ge²⁺, deep-level traps in low-dimensional materials, poor interfacial contact, and limited understanding of defect formation mechanisms.

Looking ahead, future research should prioritize the development of robust synthesis protocols that stabilize divalent cations, exploit machine learning-guided materials discovery for novel compositions, and leverage metavalent bonding concepts to explain emergent properties beyond traditional lone-pair models. Furthermore, integrating high-throughput computational screening with experimental validation will accelerate the identification of next-generation optoelectronic materials. By combining rational design principles with advanced characterization techniques, researchers can unlock the full potential of ns²-cation-based semiconductors—offering a sustainable, high-performance alternative to lead-based perovskites in future energy and information technologies.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com

Metal-organic frameworks (MOFs) have emerged as a promising class of materials due to their high surface area, tunable porosity, and versatile functionality. In this study, spindle-shaped cerium-porphyrin-based MOFs (Ce-TCPP) were successfully synthesized using a rapid microwave-assisted hydrothermal method. The synthesis process was completed within just 2 hours, significantly reducing the time required compared to conventional methods that typically take over 12 hours. This approach leverages the uniform heating provided by microwaves to accelerate nucleation and crystal growth, resulting in highly crystalline nanomaterials with controlled morphology.

The Ce-TCPP samples were prepared by mixing mesotetra(4-carboxyphenyl)porphine (TCPP), cerium nitrate hexahydrate (Ce(NO₃)₃·6H₂O), and pyrazine in a DMF/ethanol mixture (3:1 v/v). After stirring for 30 minutes, the solution was subjected to microwave irradiation at 100 °C for 2 hours. The resulting dark brown precipitate was collected through centrifugation and dried under vacuum at 60 °C for 8 hours. Powder X-ray diffraction (PXRD) analysis confirmed the successful formation of Ce-TCPP, with characteristic peaks matching simulated patterns, indicating high crystallinity. Fourier-transform infrared spectroscopy (FTIR) revealed coordination between Ce³⁺ ions and carboxylate groups of TCPP, evidenced by asymmetric (1585 cm⁻¹) and symmetric (1402 cm⁻¹) stretching vibrations of the carboxylate ligands, consistent with a bridging bidentate coordination mode.

Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images showed uniform spindle-shaped nanorods with lengths up to 1 μm and diameters around 300 nm. The BET surface area of Ce-TCPP was measured at 36.4 m²/g, with a mesoporous nature confirmed by Barrett-Joyner-Halenda (BJH) pore size distribution analysis. UV-Vis diffuse reflectance spectroscopy (DRS) indicated strong absorption across both UV and visible light regions, with a calculated band gap of approximately 2.25 eV. X-ray photoelectron spectroscopy (XPS) further confirmed the coexistence of Ce³⁺ and Ce⁴⁺ oxidation states, with binding energies at 903.6 eV and 906.1 eV corresponding to Ce³⁺ and Ce⁴⁺, respectively. These results collectively demonstrate the successful synthesis of well-defined Ce-TCPP MOFs with desirable structural and optical properties suitable for photocatalytic applications.

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**Partial Thermal Decomposition to Form CeO₂/N-Doped Carbon/Ce-TCPP Heterostructures**

To enhance the functional performance of Ce-TCPP for environmental remediation, a low-temperature pyrolysis treatment under nitrogen atmosphere was employed to partially decompose the MOF precursor into a novel heterostructured composite: CeO₂/N-doped carbon/Ce-TCPP.MRPL28 Antibody site The thermal treatment was conducted at temperatures ranging from 300 °C to 550 °C for approximately 2 hours.CD163 Antibody Technical Information The resulting materials were designated as CeO₂/NC/Ce-TCPP-x (x = calcination temperature).

PXRD patterns revealed that the characteristic peaks of Ce-TCPP disappeared above 500 °C, indicating complete decomposition. However, at lower temperatures (300–450 °C), partial preservation of the original framework structure was observed, suggesting incomplete carbonization. BET surface area measurements showed a significant reduction with increasing temperature—from 440.3 m²/g at 300 °C to only 285.7 m²/g at 450 °C—indicating structural densification and pore collapse. Meanwhile, average pore diameter increased from 10.4 nm to 33.6 nm, likely due to the release of volatile species during pyrolysis.

UV-Vis DRS results demonstrated that the absorbance peak of Ce-TCPP vanished after annealing above 500 °C, confirming full carbonization. SEM and TEM analyses revealed that while the spindle morphology was partially retained even at 450 °C, more debris formed at higher temperatures. High-resolution TEM imaging of CeO₂/NC/Ce-TCPP-450 showed clear lattice fringes with a spacing of 0.31 nm, corresponding to the (111) plane of CeO₂. Elemental mapping confirmed homogeneous distribution of C, Ce, N, and O elements, with Ce and O concentrated in certain particles, indicating localized formation of CeO₂.

XPS analysis provided detailed insight into chemical changes during pyrolysis. The C 1s peak shifted toward lower binding energy, indicating conversion of carboxyl groups into graphitic carbon. The N 1s spectrum evolved from pyrrolic N (397.5 eV) to graphitic N (397.9 eV) as temperature increased, demonstrating nitrogen doping into the carbon matrix. The O 1s signal weakened at 531.8 eV (carboxylic groups) and strengthened at 533.2 eV (Ce-O bonds), confirming the breakdown of organic linkers and formation of Ce–O bonds. Notably, a new Ce⁴⁺ peak appeared at 917.3 eV above 450 °C, suggesting partial oxidation of Ce³⁺ to Ce⁴⁺. Based on elemental analyzer and XPS data, the CeO₂/NC/Ce-TCPP-450 sample contained ~5.1 wt% CeO₂, ~93.57 wt% Ce-TCPP, and ~2.18 wt% N-doped carbon, confirming the formation of a hybrid nanocomposite.

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**Enhanced Photocatalytic Activation of Peroxymonosulfate Under Visible Light**

The CeO₂/NC/Ce-TCPP heterostructures exhibited exceptional performance in activating peroxymonosulfate (PMS) for the degradation of various organic pollutants under visible light. A series of control experiments demonstrated that neither PMS alone nor visible light alone induced significant degradation of rhodamine B (RhB). Similarly, Ce-TCPP or CeO₂ alone showed minimal activity without PMS. However, when CeO₂/NC/Ce-TCPP-450 was combined with PMS under visible light, RhB removal reached over 99% within just 20 minutes—a dramatic improvement compared to other conditions.

Kinetic analysis revealed that the reaction rate constant (k) followed the order: k(PMS + catalyst + visible light, 0.2015 min⁻¹) > k(PMS + catalyst, 0.0224 min⁻¹) > k(PMS + visible light, 0.0064 min⁻¹) > k(sole PMS, 0.0039 min⁻¹). The fact that k(PMS + catalyst + visible light) exceeded the sum of the individual contributions confirms synergistic enhancement driven by visible light.PMID:34970859 Total organic carbon (TOC) analysis showed that 65% of RhB was mineralized into CO₂ and H₂O, indicating effective destruction rather than mere transformation.

The catalyst also demonstrated broad applicability. It achieved near-complete degradation (>94%) of methylene blue (MB), methyl orange (MO), tetracycline (TCL), and oxytetracycline (OTC) within 60 minutes under identical conditions. Cycling tests over five consecutive runs showed only minor activity loss, and post-reaction characterization via XRD, SEM, TEM, and XPS confirmed structural and compositional stability. ICP-MS analysis detected only 37 ppb of leached Ce, far below regulatory limits, highlighting excellent reusability and environmental safety.

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**Mechanistic Insights into Z-Scheme Charge Transfer and Radical Generation**

To understand the origin of enhanced activity, radical scavenging and electron spin resonance (ESR) experiments were conducted. Addition of tert-butanol (OH scavenger) most significantly suppressed RhB degradation, followed by ethanol (scavenges both OH and SO₄⁻), and formate (h⁺ scavenger), indicating that hydroxyl radicals (OH) and sulfate radicals (SO₄⁻) are dominant reactive species.

ESR results using DMPO and TEMPO probes confirmed the generation of OH and SO₄⁻ radicals only when CeO₂/NC/Ce-TCPP-450 was combined with PMS. Under visible light, radical signals intensified significantly, proving light-driven activation. The band diagram constructed from UPS and DRS data revealed a Z-scheme configuration: CeO₂ has a more positive valence band (+3.06 eV vs NHE) than Ce-TCPP (+2.07 eV), enabling direct oxidation of surface OH⁻ to generate OH radicals. Simultaneously, photogenerated electrons in CeO₂’s conduction band transfer to N-doped carbon and recombine with holes in Ce-TCPP’s valence band, effectively separating charge carriers.

This Z-scheme mechanism not only suppresses electron-hole recombination but also enhances redox potential. PL and TRPL measurements supported this—CeO₂/NC/Ce-TCPP-450 exhibited the lowest fluorescence intensity and longest lifetime (14.9 ns), outperforming both CeO₂ (9.3 ns) and Ce-TCPP (10.5 ns). These findings confirm efficient spatial separation of charge carriers, leading to prolonged carrier lifetime and enhanced catalytic efficiency.

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**Conclusion and Implications for Environmental Remediation**

This study presents a novel strategy for fabricating highly efficient MOF-derived photocatalysts through partial thermal decomposition of Ce-TCPP MOFs. The resulting CeO₂/N-doped carbon/Ce-TCPP heterostructure functions as a Z-scheme photocatalyst, enabling superior visible-light-driven activation of peroxymonosulfate for the degradation of diverse organic pollutants. The synergy between CeO₂, N-doped carbon, and intact Ce-TCPP units facilitates charge separation, expands light absorption, and provides abundant active sites for radical generation.

The system demonstrates high activity, stability, and reusability, making it a promising candidate for practical water purification technologies. This work opens new avenues for designing advanced MOF-based catalysts for sustainable environmental remediation, particularly in addressing persistent organic contaminants such as dyes and antibiotics in aqueous systems.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com

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