Search Results (4,734)

The thermal decomposition performance of ammonium perchlorate (AP) is a key factor in regulating the combustion of composite solid propellants, and its catalytic decomposition process is considered a typical multiphase catalytic process. The exposure of catalytic centers during multiphase catalysis is a key factor affecting catalytic performance. In response to the problem of low atomic utilization efficiency of traditional metal oxide catalysts, this study successfully prepared nitrogen-doped carbon-supported single-atom cobalt catalyst (SACo-PC-X) using the “zinc volatilization pore formation and nitrogen anchoring” method with inexpensive biomass as the precursor. Aberration-corrected transmission electron microscopy, together with XPS and XRD analyses, suggests that Co species are predominantly stabilized in an atomically dispersed Co-N_x configuration. This catalyst exhibits excellent catalytic performance for the thermal decomposition of AP, significantly reducing its high-temperature decomposition temperature from 433.5 °C to 322.7 °C (The cobalt content in the system is less than 0.2%). Gas studies have shown that Co-N_x sites efficiently accelerate the oxidation process of NH₃ by promoting electron transfer, resulting in a significant increase in the proportion of N₂O gas. This work not only provides an efficient and stable new catalyst for AP decomposition, but also offers new ideas for designing energetic material decomposition catalysts at the atomic level. Full article

Personal growth is a central aspect of development and well-being during young adulthood, yet sexually diverse and gender-diverse (SGD; a more inclusive term for LGBTQ+) young adults navigate this process within unique contexts shaped by identity, stress, and varying levels of social support. Despite growing visibility and social recognition of SGD identities in the United States, SGD individuals continue to face prejudice and discrimination, which negatively affects their physical and psychological health. Research indicates that stigmatized and marginalized populations with greater psychosocial resources are better able to cope with identity-related stressors. Yet, scholarship on coping with stigma and discrimination remains largely disconnected from research on social support, personal growth, and thriving within close relationships. The present observational study of SGD young adults (N = 400) examines how identity-affirming support from close others contributes to positive well-being outcomes, specifically personal growth, self-concept clarity, and thriving. Whereas much prior work focuses on how support buffers stress, we examine its role across stressors and opportunities for growth, experienced broadly and in relation to SGD identity. Our findings underscore the critical role that close relationships play in fostering social safety and personal growth for SGD young adults navigating identity development. Full article

Layered double hydroxides (LDHs) have attracted growing interest as multifunctional materials due to their tunable composition, layered architecture, and versatile surface and interlayer chemistry. In addition to their use as bulk catalysts, LDHs are increasingly explored as functional and catalytic coatings, where immobilization on solid substrates enables enhanced stability, reusability, and control over interfacial reactivity. This review examines how composition, architecture, and reactivity relationships in LDHs can be leveraged to design multifunctional LDH-based coatings able to support catalytic processes. Key design strategies based on cation composition, interlayer anions, defect engineering, and hierarchical architectures are discussed in the context of surface-deposited systems. Synthetic approaches relevant to coatings, including in situ growth, post-synthetic modification, and calcination–reconstruction routes, are summarized alongside mechanistic insights into acid–base, redox, and synergistic multi-site catalysis. Finally, applications in catalytic coatings, and environmentally relevant processes are highlighted, with emphasis on structure–activity correlations, coating durability, and resistance to leaching. This review provides a framework for the rational development of multifunctional LDH coatings for catalytic and energy-related applications. Full article

This paper presents a holistic review of Liquid Organic Hydrogen Carriers (LOHCs), focusing on typology, energy efficiency, techno-economic analyses (TEAs), and life cycle assessments (LCAs). Initially, the study categorizes various LOHC systems documented in existing literature, outlining their chemical structures, catalysts, properties, and main applications. This survey aims to provide a comprehensive understanding of LOHC varieties, making it easier to compare across different types. Next, we explore the efficiency of LOHC systems by reviewing hydrogenation and dehydrogenation energy requirements, catalyst behavior, heat-management constraints, product-separation needs, and net energy storage capabilities. This review also includes reaction stoichiometries, recent catalyst and reactor developments, catalyst-deactivation mechanisms, and heat-integration options for high-temperature dehydrogenation. Finally, our investigation offers a detailed evaluation of TEA and LCA for LOHC systems found in the literature. By exploring economic feasibility and environmental impact, this study presents a complete picture of the sustainability of LOHC deployment. It includes assessments of life-cycle carbon emissions, levelized cost, supply-chain configuration, carrier recyclability, infrastructure compatibility, renewable-electricity capacity factors, and heat-recovery assumptions. Our findings aim to contribute to hydrogen storage and transport research by identifying the most important technical, economic, and environmental trade-offs for LOHC systems. By addressing gaps in recent literature, TEA comparability, and LCA coverage, this paper seeks to advance the development of LOHC technologies and support their broader adoption in a green and sustainable energy landscape. Full article

With the rapid development of the pharmaceutical industry and animal husbandry, conventional wastewater treatment plants have difficulty effectively degrading the widely occurring ceftiofur sodium (CEF) in aquatic environments. To address this issue, this study successfully loaded Fe/Co-ZIF onto carbon nanofibers (CNF), thereby preparing Fe/Co-ZIF@CNF composites with well-dispersed supported materials and a stable structure. The as-prepared Fe/Co-ZIF@CNF was further applied in a persulfate-based advanced oxidation system (SR-AOPs) for CEF degradation and exhibited good catalytic performance. When the Fe/Co molar ratio was 1.25:1, the Fe/Co-ZIF_1.25 material achieved a CEF degradation efficiency, k_obs value, and TOC removal rate of 94.0%, 0.135 min⁻¹, and 43.8%, respectively. Radical quenching experiments preliminarily indicated that SO₄^•− played a dominant role in the reaction system, while •OH and ¹O₂ also made non-negligible contributions to CEF degradation. This work provides a new strategy for constructing composite catalysts based on carbon nanofiber-supported polymetallic MOFs. Full article

A sustainable and scalable one-pot impregnation protocol, avoiding high-temperature calcination/activation, was employed to prepare Pd/Al₂O₃ (0.24 wt%), Pd/TiO₂ (0.18 wt%), Pd/ZrO₂ (0.21 wt%), Pd/SiO₂ (0.37 wt%), Rh/Al₂O₃ (0.18 wt%), and Rh/TiO₂ (0.15 wt%). Support effects on activity, selectivity, and recyclability of these low-metal content heterogeneous catalysts were investigated, using (E)-cinnamaldehyde and levulinic acid as probe molecules. In cinnamaldehyde hydrogenation, Pd catalysts were highly effective for chemoselective C=C reduction to 3-phenylpropanal under mild conditions, with Pd/TiO₂ displaying the highest activity and robust performance over several recycles. However, the Lewis acidity of TiO₂ promoted a solvent-involving side reaction in 2-propanol, with hemiacetal and ether formation, highlighting that apparent selectivity is strongly shaped by support acidity and product residence time. Rh/Al₂O₃ exhibited lower activity than Pd analogues but near-quantitative selectivity to the saturated aldehyde, whereas Rh/TiO₂ again favored hemiacetal formation. In levulinic acid hydrogenation, Pd catalysts were essentially inactive toward ketone hydrogenation even at elevated temperature and H₂ pressure, while Rh catalysts achieved high productivity with exclusive formation of γ-valerolactone, Rh/Al₂O₃ being the most active at comparatively mild pressures. Full article

The removal of recalcitrant industrial dyes from wastewater has emerged as a critical environmental challenge, particularly in the context of the accelerating decline of global freshwater reserves. Given that these contaminants originate predominantly from the effluents of textile, chemical, and related manufacturing sectors, the deployment of advanced treatment technologies prior to discharge is imperative to mitigate their ecological impact. This study investigates the photocatalytic degradation of indigo carmine using a synthesized MgAl–LDH material. LDH is shown to act as an active photocatalytic component rather than a support, with its remarkably simple synthesis offering a practical alternative to the complex catalysts dominating the current literature. The catalyst’s structural, morphological, and surface characteristics were comprehensively validated through XRD, SEM, EDX, and BET analyses. The catalyst was evaluated under varying hydrogen peroxide doses and across an initial dye concentration range of 5 × 10⁻⁵ to 5 × 10⁻⁴ M. Increasing the H₂O₂ volume (3.5–20 mL, corresponding to H₂O₂ excess ratios of 17.5–100) significantly enhanced the oxidation rate, whereas higher dye concentrations reduced efficiency due to photon competition and partial saturation of catalytic sites. These experiments provided the basis for extracting kinetic parameters and assessing the mechanistic pathways governing the photocatalytic process. The kinetic behavior of indigo carmine degradation was evaluated by fitting the experimental data to zero-order, first-order, and second-order empirical models to identify the rate law that best describes the reaction. Reusability tests showed that MgAl–LDH maintains high activity over multiple cycles, with only a moderate decline, demonstrating its stability and suitability for practical wastewater treatment applications. Full article

In this study, catalytic wet oxidation of highly concentrated antibiotic-containing pharmaceutical wastewater was investigated under mild operating conditions (200–280 °C, 2.0~6.0 MPa) using a CuCe/Al₂O₃catalyst, synthesized via the co-impregnation method. The physicochemical properties of the catalyst were characterized by SEM-EDS, TEM, XPS. The catalytic performance results demonstrated that the CuCe/Al₂O₃ catalyst exhibited optimal catalytic activity, achieving a chemical oxygen demand (COD) removal efficiency of 86.3% under the following conditions: reaction temperature 280 °C, reaction time 60 min, initial oxygen pressure 1.2 MPa, and catalyst dosage 5.0 g/L. The superior catalytic performance was attributed to the synergistic effect between Cu and Ce species as well as their excellent dispersion on the support. Kinetic analysis revealed that the oxidation process proceeded via two sequential reaction steps and followed an apparent first-order kinetic model. Overall, this catalytic wet oxidation process offers an efficient pretreatment strategy for highly concentrated pharmaceutical wastewater containing antibiotics. Full article

This study examines the influence of the chemical nature and molecular structure of external electron-donor compounds on the slurry synthesis of isotactic polypropylene in a hydrocarbon diluent using a titanium–magnesium Ziegler–Natta catalyst. Propylene polymerization was carried out at constant temperature, pressure, hydrogen concentration, and fixed molar ratios of the catalyst system components. Alkoxysilanes with different structures were used as external donors: dicyclopentyldimethoxysilane, cyclohexylmethyldimethoxysilane, diisobutyldimethoxysilane, and diethylaminotriethoxysilane; di-n-butyl phthalate was used as a reference compound. It was shown that external donors decrease catalytic activity relative to the donor-free system but increase stereospecificity, as indicated by a lower xylene-soluble fraction and a higher isotactic index of polypropylene. Dicyclopentyldimethoxysilane demonstrated the strongest stereoregulating effect, providing the lowest content of xylene-soluble polymer. The donor structure significantly affected the molecular weight, rheological, and thermal characteristics of polypropylene, including melt flow rate, viscosity-average molecular weight, melting temperature, melting enthalpy, and crystallinity. Comparison with literature data for catalyst systems differing in internal and external donors, as well as in synthesis conditions, showed that catalyst activity and the stereospecificity of the catalyst system may be determined not only by process parameters but also by the electron-donor environment of the active sites. The results support established concepts of external-donor action in Ziegler–Natta catalysis and provide a comparative assessment of alkoxysilane donors and di-n-butyl phthalate under slurry polymerization conditions. Full article

Nitrophenols, despite their wide synthetic utility in the specialty chemical industry, are recognized as toxic and can pose a serious environmental hazard. A popular strategy for the purification of wastewater containing nitrophenols is their catalytic reduction to the corresponding aminophenols in the presence of supported transition metal catalysts. However, the practical application of such systems is hindered by tedious catalyst manufacturing protocols and strong dependence on the catalyst/support microstructure. Herein, a series of CoO_x@SiO₂ composites was prepared by a direct reduction of aqueous solutions of Co(II) salts (Co(OAc)₂, CoCl₂, and CoF₂) with fumed silica having a triethoxysilane-modified surface. The prepared composites, despite the observed low cobalt content (0.1–0.2 wt%), proved highly effective in reducing 2-nitrophenol to 2-aminophenol, demonstrating a cost-effective, readily available non-precious-metal-based system for the remediation of nitrophenols from contaminated water. Full article

Direct methanol fuel cells (DMFCs) have attracted considerable attention recently for various applications ranging from portable ones to transportation. The efficiency of DMFCs depends on the kinetics of anodic and cathodic electrocatalysts. Due to sluggish anodic methanol oxidation reaction (MOR), DMFCs require an effective and bifunctional catalyst for promoting efficient MOR. The state-of-the-art MOR catalysts, such as Pt/C and Pt-Ru/C, have been shown to exhibit reasonable MOR activity; however, the insufficient mass activity and poor stability of carbon-supported catalysts have been a major limitation, requiring an alternative, efficient, electrocatalyst that exhibits high mass and specific activities. In addition, electrocatalysts without any carbon support (self-supported electrocatalysts) further mitigate their poor stability and therefore enhance their durability. In this regard, metal aerogel catalysts, which are entirely composed of metallic networks, recently attained special interest due to their specific advantages over conventional carbon supports, such as high catalyst utilization and improved electronic conductivity and stability. In this review, we systematically reviewed various metal aerogel catalysts developed for MOR since their first discovery in 2009. The metal aerogel demonstrated superior MOR performance relative to carbon-supported commercial catalysts, with enhancements ranging from 2-fold to 22-fold of mass activity. We also statistically compared the mass activity of metal aerogels with traditional carbon-supported, non-carbon-supported, and advanced shape-controlled catalysts and found that metal aerogels exhibited high mass activities compared to other catalyst systems. Therefore, we clearly establish that metal aerogel catalysts possess great potential as efficient MOR catalysts in DMFCs. In addition, we have provided several future research directions and strategies for further development of metal aerogel-integrated DMFC devices. Full article

Chlorpyrifos, a widely used organophosphate pesticide, poses significant environmental risks due to its persistence and the formation of toxic transformation products. Despite extensive research on iron-based Fenton systems, the application of manganese oxides, particularly α-Mn₂O₃, in chlorpyrifos degradation remains insufficiently explored. In this study, we investigated the catalytic performance of α-Mn₂O₃ in Fenton and visible-light-driven photo-Fenton processes for the degradation of chlorpyrifos in aqueous systems. Chlorpyrifos oxon was identified as a transient intermediate, detected at trace levels, supporting an oxidative degradation pathway. Kinetic analysis revealed pseudo-first-order behavior, with comparable rate constants for Fenton reactions at different catalyst loadings (0.0033 min⁻¹ for 5 mg and 0.0028 ± 0.0006 min⁻¹ for 10 mg), indicating that the process is not limited by catalyst concentration under the investigated conditions. In contrast, the photo-Fenton system exhibited a higher rate constant (0.0042 min⁻¹) and significantly improved degradation efficiency, highlighting the role of visible-light activation. The highest removal rates of chlorpyrifos were 86.24% for Fenton experiments and 96.05% for the photo-Fenton experiment, respectively. The enhanced performance is attributed to the photocatalytic properties of α-Mn₂O₃, including its narrow bandgap and the facilitation of Mn³⁺/Mn²⁺ redox cycling, which promotes reactive oxygen species generation. These findings demonstrate that α-Mn₂O₃ is a promising non-iron catalyst for advanced oxidation processes and provide new insights into manganese-mediated Fenton-like mechanisms for the removal of organophosphate contaminants. Full article

Rhodamine B (RhB) is a typical xanthene-based cationic dye. Its widespread application has brought serious safety and environmental risks. Heterogeneous Fenton systems based on zero-valent iron (Fe⁰) are promising for RhB degradation. However, bare Fe⁰ suffers from severe agglomeration and surface passivation. In this study, alumina with a large pore volume and high specific surface area was employed as a support to enhance Fe⁰ dispersion and stability. The catalyst was prepared via a glucose-assisted carbothermal reduction method, and the formation of Fe⁰ was confirmed by X-ray diffraction and electron microscopy analyses. Under optimal conditions (pH = 3.58, catalyst dosage = 0.8 g·L⁻¹, H₂O₂ = 10 mM), 10 mg·L⁻¹ RhB was completely degraded within 25 min, with a pseudo-first-order rate constant of 0.432 min⁻¹. This exhibits a faster degradation rate and efficiency advantage. Radical quenching experiments indicated that hydroxyl radicals (•OH) were the dominant reactive species, while singlet oxygen (¹O₂) also contributed to the degradation process. Two primary degradation pathways, including N-deethylation and hydroxylation, were identified. The catalyst showed moderate reusability with slight deactivation after repeated cycles. This study demonstrates that tailoring the pore structure of alumina supports is an effective strategy to enhance Fe⁰ dispersion, mass transfer, and catalytic performance in heterogeneous Fenton systems. Full article

In order to improve the assessment of the dynamic risk of urban waterlogging, this study addresses the limitations of existing methods in capturing the responses of surface roads and subway systems to inundation, as well as the resulting spatiotemporal risks. Using the Hanyang District in Wuhan as a case study, the research proposes a framework for assessing urban waterlogging risks based on the dynamic inundation responses of surface and underground transport systems under various rainfall scenarios. The waterlogging process is simulated using seven representative rainfall scenarios with a hydrodynamic model that integrates a one-dimensional pipe network, a two-dimensional surface overland flow model, and a generalized underground space model. A coupled road–subway transportation network is developed to analyze traffic capacity degradation, path redistribution, and cascading failures caused by waterlogging disturbances. Quantified dynamic response indicators are integrated into the H-E-V-C framework to assess dynamic urban waterlogging risk. The results indicate that direct failure caused by water accumulation is typically the primary catalyst for extensive degradation of the transportation network, while the expansion of congestion and localized overload failures further exacerbate cascading effects. Different rainfall patterns influence not only peak risk but also the duration and spatial development of high-risk areas. Incorporating the dynamic response of the transport system enables a more accurate assessment of the degradation of emergency accessibility and the ongoing accumulation of localized high-risk areas. These findings highlight the importance of dynamic risk assessment in identifying time-varying urban vulnerabilities and supporting the planning of sustainable urban drainage, traffic management, and phased early warning systems. Full article

This work presents a sustainable strategy for the fabrication of multifunctional silver nanoparticles (Ag-NPs) and Ag/jute nanocomposites using Erythroxylum coca tea waste extract as a bioreducing and stabilizing agent, combined with picosecond pulsed laser irradiation. UV–Vis spectroscopy and transmission electron microscopy revealed the formation of Ag-NPs with diverse morphologies and broad size distributions, which became significantly more uniform after laser post-treatment without the need for additional chemical reagents. Following laser irradiation, the initially broad Ag surface plasmon resonance (SPR) peak transformed into a symmetric Gaussian-shaped band, centered at 407 ± 3 nm for all the Ag-NPs systems. The catalytic performance of unsupported Ag-NPs and Ag-NPs supported on jute fibers was comparatively evaluated by degrading Congo red (CR) dye, revealing that the supported nanocomposites exhibited enhanced catalytic stability, higher pollutant removal efficiency, and improved catalyst recovery. Furthermore, multicomponent catalytic reduction experiments involving CR and 4-nitrophenol (4-NP) in the presence of NaBH₄ revealed simultaneous degradation and reduction pathways mediated by the Ag/jute nanocomposites, as evidenced by the emergence of new absorption bands during the reaction. In parallel, the synthesized Ag-NPs demonstrated pronounced antimicrobial activity against Escherichia coli, generating well-defined inhibition zones. Beyond conventional approaches centered on nanoparticle synthesis and morphology optimization, this study establishes a platform that combines agricultural waste valorization, laser-assisted nanoparticle engineering, and natural-fiber-supported nanocomposite fabrication, enabling efficient remediation of both single- and multicomponent pollutant systems while promoting catalyst reusability and environmental sustainability. These findings demonstrate the Ag/jute nanocomposites as sustainable and scalable catalytic materials for wastewater remediation and antimicrobial applications. Full article