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2.
Nurs Res Pract ; 2024: 9823144, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39247450

RESUMEN

Background: The acute myocardial infarction mortality risk rises by 8% per year for every 30-minute delay in early coronary intervention following the onset of symptoms. Thus, it is important to reduce the door-to-balloon time as much as possible, especially in hospitals where early coronary intervention is carried out within 90 minutes. Aim: The purpose of this study was to determine the impact of King Abdullah Medical City's strategies on balloon time for patients with ST elevation myocardial infraction. Methods: Prospective observational research was conducted in King Abdullah Medical City. This study included 67 patients who had a primary percutaneous coronary intervention. Data were collected in Hajj 2023 through direct observation using a checklist that included two parts: (I) patients' demographic characteristics and relevant time intervals. The data were analyzed using descriptive statistics (frequency and percentage; median and interquartile range) and inferential statistics (Mann-Whitney U test, Kruskal-Wallis H test, Spearman correlation coefficient test). Results: It was noted that the median overall door-to-balloon time was 68 minutes for direct admission patients and 100 minutes (median) for interhospital transferred patients, with a statistically significant P value of 0.001. DTBT had no significant correlation with either the length of stay or hospital mortality rates (P > 0.05). Conclusions: King Abdullah Medical City accomplished an international benchmark in door-to-balloon time for ST elevation myocardial infraction patients visiting the hospital for percutaneous coronary intervention during the hajj season. Healthcare organizations can take proactive steps to optimize the management of STEMI cases. This includes establishing efficient communication channels, standardizing protocols, and facilitating seamless transitions between healthcare facilities.

3.
Nat Mater ; 2024 Aug 08.
Artículo en Inglés | MEDLINE | ID: mdl-39117910

RESUMEN

Metal-organic frameworks (MOFs) have captivated researchers for over 25 years, yet few have successfully transitioned to commercial markets. This Perspective elucidates the progress, challenges and opportunities in moving MOFs to market, focusing on applied research. The five applied research steps that enable technology development and demonstration are reviewed: synthesis, forming, processing (washing and activation), prototyping and compliance. Furthermore, the importance of a comprehensive techno-economic analysis incorporating a complete picture of costs and revenues is discussed. Readers can use the understanding of applied research presented herein to tackle their MOF commercialization challenges.

4.
Artículo en Inglés | MEDLINE | ID: mdl-39163097

RESUMEN

The versatility of metal-organic frameworks (MOFs) has led to groundbreaking applications in a wide variety of fields, especially in the areas of energy, environment, and sustainability. For example, MOFs can be designed for high uptake of toxic gases and pollutants, such as CO2, NH3, and SO2, but designing a single MOF that shows tangible uptake for all of these gases is challenging due to the differences in the chemical and physical properties of these molecules. To this end, integrating multiple MOFs onto textile fibers and crafting various structures have emerged as pivotal developments, enhancing framework durability and usability. MOF composites prepared on readily available textile fibers offer the flexibility essential for critical applications, including heterogeneous catalysis, chemical sensing, toxic gas adsorption, and drug delivery, while preserving the unique characteristics of MOFs. This study introduces a scalable and adaptable method for seamlessly embedding multiple high-performing MOFs onto a single textile fiber using a dip-coating method. We explored the uptake capacity of these multi-MOF composites for CO2, NH3, and SO2 and observed a performance similar to that of traditional powdered materials. Along with harmful gas adsorption, we also have evaluated the permeation and reactivity of these MOF/textile composites toward chemical warfare agents (CWAs) like GD (soman), HD (mustard gas), and VX. In combination, these results demonstrate a fundamental advancement toward establishing a consistent strategy for the hydrolysis of nerve agents in real-world scenarios. This approach can substantially increase the protection toward CWAs and enhance the effectiveness of protective equipment such as fabrics for protective garments. This dip-coating method for the integration of multiple MOFs on a single textile fiber unlocks a wealth of possibilities and paves the way for future innovations in the deployment of MOF-based composites.

5.
Circ Cardiovasc Imaging ; 17(8): e016852, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-39163376

RESUMEN

BACKGROUND: Right ventricular (RV) dysfunction is known to impact prognosis, but its determinants in coronary artery disease are poorly understood. Stress cardiac magnetic resonance (CMR) has been used to assess ischemia and infarction in relation to the left ventricle (LV); the impact of myocardial tissue properties on RV function is unknown. METHODS: Vasodilator stress CMR was performed in patients with known coronary artery disease at 7 sites between May 2005 and October 2018. Myocardial infarction was identified on late gadolinium enhancement-CMR, and infarct transmurality was graded on a per-segment basis. Ischemia was assessed on stress CMR based on first-pass perfusion and localized by using segment partitions corresponding to cine and late gadolinium enhancement analyses. RV function was evaluated by CMR-feature tracking for primary analysis with a global longitudinal strain threshold of 20% used to define impaired RV strain (RVIS); secondary functional analysis via RV ejection fraction was also performed. RESULTS: A total of 2604 patients were studied, among whom RVIS was present in 461 patients (18%). The presence and magnitude of RVIS were strongly associated with LV dysfunction, irrespective of whether measured by LV ejection fraction or wall motion score (P<0.001 for all). Regarding tissue substrate, regions of ischemic and dysfunctional myocardium (ie, hibernating myocardium) and infarct size were each independently associated with RVIS (both P<0.001). During follow-up (median, 4.62 [interquartile range, 2.15-7.67] years), 555 deaths (21%) occurred. Kaplan-Meier analysis for patients stratified by presence and magnitude of RV dysfunction by global longitudinal strain and RV ejection fraction each demonstrated strong prognostic utility for all-cause mortality (P<0.001). RVIS conferred increased mortality risk (hazard ratio, 1.35 [95% CI, 1.11-1.66]; P=0.003) even after controlling for LV function, infarction, and ischemia. CONCLUSIONS: RVIS in patients with known coronary artery disease is associated with potentially reversible LV processes, including LV functional impairment due to ischemic and predominantly viable myocardium, which confers increased mortality risk independent of LV function and tissue substrate.


Asunto(s)
Enfermedad de la Arteria Coronaria , Imagen por Resonancia Cinemagnética , Imagen de Perfusión Miocárdica , Disfunción Ventricular Derecha , Función Ventricular Derecha , Humanos , Masculino , Femenino , Enfermedad de la Arteria Coronaria/fisiopatología , Enfermedad de la Arteria Coronaria/complicaciones , Enfermedad de la Arteria Coronaria/diagnóstico por imagen , Persona de Mediana Edad , Anciano , Imagen por Resonancia Cinemagnética/métodos , Disfunción Ventricular Derecha/fisiopatología , Disfunción Ventricular Derecha/etiología , Disfunción Ventricular Derecha/diagnóstico por imagen , Función Ventricular Derecha/fisiología , Imagen de Perfusión Miocárdica/métodos , Valor Predictivo de las Pruebas , Volumen Sistólico/fisiología , Función Ventricular Izquierda/fisiología , Pronóstico , Estados Unidos/epidemiología
6.
J Colloid Interface Sci ; 674: 1071-1082, 2024 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-39013277

RESUMEN

Hypothesis Atomistically-detailed models of surfactants provide quantitative information on the molecular interactions and spatial distributions at fluid interfaces. Hence, it should be possible to extract from this information, macroscopical thermophysical properties such as interfacial tension, critical micelle concentrations and the relationship between these properties and the bulk fluid surfactant concentrations. Simulations and Experiments Molecular-scale interfacial of systems containing n-dodecyl ß-glucoside (APG12) are simulated using classical molecular dynamics. The bulk phases and the corresponding interfacial regions are all explicitly detailed using an all-atom force field (PCFF+). During the simulation, the behaviour of the interface is analyzed geometrically to obtain an approximated value of the critical micelle concentration (CMC) in terms of the surfactant area number density and the interfacial tension is assessed through the analysis of the forces amongst molecules. New experimental determinations are reported for the surface tension of APG12 at the water/air and at the water/n-decane interfaces. Findings We showcase the application of a thermodynamic framework that inter-relates interfacial tensions, surface densities, CMCs and bulk surfactant concentrations, which allows the in silico quantitative prediction of interfacial tension isotherms.

7.
Open Forum Infect Dis ; 11(7): ofae328, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38989532

RESUMEN

Background: Recent advances in shotgun metagenomic sequencing (sMGS) for detecting microbial cell-free DNA (mcfDNA) in peripheral blood have shown promise across various patient populations. This study evaluates the application of sMGS for diagnosing osteoarticular infections (OAIs), a condition with significant diagnostic challenges. Methods: We conducted a retrospective analysis on 73 patients suspected of OAIs at the Mayo Clinic from 2019 to 2023, incorporating mcfDNA sMGS (Karius test [KT]) into their diagnostic evaluation. We categorized the clinical impact of KT on OAI diagnoses and management into 4 distinct outcomes. (1) KT was able to confirm an established diagnosis, (2) KT supported noninfectious diseases diagnosis, (3) KT established an unsuspected diagnosis, (4) KT did not add relevant information. Results: In our cohort, KT was performed in 73 patients. Among the infected individuals, KT yielded positive results in 22 of 43 (51.2%) cases. Of these 22 cases, 11 (50%) showed agreement with conventional diagnostic workup, whereas in 5 (22.7%) cases, the KT established an unsuspected diagnosis. Native vertebral osteomyelitis diagnosis (P < .001) or OAIs with concomitant presence of endocarditis or endovascular infection (P = .005) were statistically associated with a definite, probable, or possible diagnostic certainty of KT result. Conclusions: In complex OAIs, KT enhanced diagnostic accuracy by 11.6%, proving especially beneficial in diagnosing native vertebral osteomyelitis and infections with concurrent endocarditis or endovascular complications. Our findings underscore the utility of KT in the diagnostic workflow for challenging OAI cases, potentially altering clinical management for a significant subset of patients.

8.
J Am Chem Soc ; 146(31): 21806-21814, 2024 Aug 07.
Artículo en Inglés | MEDLINE | ID: mdl-39056747

RESUMEN

Water adsorption/desorption cyclability of porous materials is a prerequisite for diverse applications, including atmospheric water harvesting (AWH), humidity autocontrol (HAC), heat pumps and chillers, and hydrolytic catalysis. However, unambiguous molecular insights into the correlation between underlying building blocks and the cyclability are still highly elusive. In this work, by taking advantage of the well-established isoreticular synthetic principle in Zr(IV) metal-organic frameworks (Zr-MOFs), we show that the inherent density of hydrogen atoms in the organic skeleton can play a key role in regulating the water sorption cyclability of MOFs. The ease of isoreticular practice of Zr-MOFs enables the successful syntheses of two pairs of isostructural Zr-MOFs (NU-901 and NU-903, NU-950 and SJTU-9) from pyrene- or benzene-cored carboxylate linkers, which feature scu and sqc topological nets, respectively. NU-901 and NU-950 comprised of pyrene skeletons carrying more hydrogen-bonding anchoring sites show distinctly inferior cyclability as compared with NU-903 and SJTU-9 built of benzene units. Single-crystal X-ray crystallography analysis of the hydrated structure clearly unveils the water molecule-involved interactions with the hydrogen-bonding donors of benzene moieties. Remarkably, NU-903 and SJTU-9 isomers exhibit outstanding water vapor sorption capacities as well as working capacities at the desired humidity range with potential implementations covering indoor humidity control and water harvesting. Our findings uncover the importance of hydrogen-bonding anchoring site engineering of organic scaffold in manipulating the framework durability toward water sorption cycle and will also likely facilitate the rational design and development of highly robust porous materials.

9.
Bioorg Chem ; 150: 107574, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-38936049

RESUMEN

Mitochondrial dynamics have pillar roles in several diseases including cancer. Cancer cell survival is monitored by mitochondria which impacts several cellular functions such as cell metabolism, calcium signaling, and ROS production. The equilibrium of death and survival rate of mitochondria is important for healthy cellular processes. Whereas inhibition of mitochondrial metabolism and dynamics can have crucial regulatory decisions between cell survival and death. The steady rate of physiological flux of both mitochondrial fission and fusion is strongly related to the preservation of cellular bioenergetics. Dysregulation of mitochondrial dynamics including fission and fusion is a critical machinery in cells accompanied by crosstalk in cancer progression and resistance. Many cancer cells express high levels of Drp-1 to induce cancer cell invasion, metastasis and chemoresistance including breast cancer, liver cancer, pancreatic cancer, and colon cancer. Targeting Drp-1 by inhibitors such as Midivi-1 helps to enhance the responsiveness of cancer cells towards chemotherapy. The review showed Drp-1 linked processes such as mitochondrial dynamics and relationship with cancer, invasion, and chemoresistance along with computational assessing of all publicly available Drp-1 inhibitors. Drp1-IN-1, Dynole 34-2, trimethyloctadecylammonium bromide, and Schaftoside showed potential inhibitory effects on Drp-1 as compared to standard Mdivi- 1. This emerging approach may have extensive strength in the context of cancer development and chemoresistance and further work is needed to aid in more effective cancer management.


Asunto(s)
Antineoplásicos , Resistencia a Antineoplásicos , Dinaminas , Neoplasias , Humanos , Dinaminas/antagonistas & inhibidores , Dinaminas/metabolismo , Antineoplásicos/farmacología , Antineoplásicos/química , Antineoplásicos/síntesis química , Resistencia a Antineoplásicos/efectos de los fármacos , Neoplasias/tratamiento farmacológico , Neoplasias/patología , Neoplasias/metabolismo , Dinámicas Mitocondriales/efectos de los fármacos , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Estructura Molecular , Animales , Quinazolinonas/farmacología , Quinazolinonas/química , Quinazolinonas/síntesis química
10.
Adv Mater ; 36(33): e2405924, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38850277

RESUMEN

Here, an ionic polymer of intrinsic microporosity (PIM) as a high-functioning supercapacitor electrode without the need for conductive additives or binders is reported. The performance of this material is directly related to its large accessible surface area. By comparing electrochemical performance between a porous viologen PIM and a nonporous viologen polymer, it is revealed that the high energy and power density are both due to the ability of ions to rapidly access the ionic PIM. In 0.1 m H2SO4 electrolyte, a pseudocapacitve energy of 315 F g-1 is observed, whereas in 0.1 m Na2SO4, a capacitive energy density of 250 F g-1 is obtained. In both cases, this capacity is retained over 10 000 charge-discharge cycles, without the need for stabilizing binders or conductive additives even at moderate loadings (5 mg cm-2). This desirable performance is maintained in a prototype symmetric two-electrode capacitor device, which has >99% Coloumbic efficiency and a <10 mF capacity drop over 2000 cycles. These results demonstrate that ionic PIMs function well as standalone supercapacitor electrodes and suggest ionic PIMs may perform well in other electrochemical devices such as sensors, ion-separation membranes, or displays.

11.
ACS Appl Mater Interfaces ; 16(23): 30296-30305, 2024 Jun 12.
Artículo en Inglés | MEDLINE | ID: mdl-38825765

RESUMEN

Polyoxometalates (POMs) are discrete anionic clusters whose rich redox properties, strong BroÌ·nsted acidity, and high availability of active sites make them potent catalysts for oxidation reactions. Metal-organic frameworks (MOFs) have emerged as tunable, porous platforms to immobilize POMs, thus increasing their solution stability and catalytic activity. While POM@MOF composite materials have been widely used for a variety of applications, little is known about the thermodynamics of the encapsulation process. Here, we utilize an up-and-coming technique in the field of heterogeneous materials, isothermal titration calorimetry (ITC), to obtain full thermodynamic profiles (ΔH, ΔS, ΔG, and Ka) of POM binding. Six different 8-connected hexanuclear Zr-MOFs were investigated to determine the impact of MOF topology (csq, scu, and the) on POM encapsulation thermodynamics.

13.
Front Cardiovasc Med ; 11: 1382418, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38903970

RESUMEN

Introduction: The evaluation of left ventricular diastolic dysfunction (LVDD) by clinical cardiac magnetic resonance (CMR) remains a challenge. We aimed to train and evaluate a machine-learning (ML) algorithm for the assessment of LVDD by clinical CMR variables and to investigate its prognostic value for predicting hospitalized heart failure and all-cause mortality. Methods: LVDD was characterized by echocardiography following the ASE guidelines. Eight demographic and nineteen common clinical CMR variables including delayed enhancement were used to train Random Forest models with a Bayesian optimizer. The model was evaluated using bootstrap and five-fold cross-validation. Area under the ROC curve (AUC) was utilized to evaluate the model performance. An ML risk score was used to stratify the risk of heart failure hospitalization and all-cause mortality. Results: A total of 606 consecutive patients underwent CMR and echocardiography within 7 days for cardiovascular disease evaluation. LVDD was present in 303 subjects by echocardiography. The performance of the ML algorithm was good using the CMR variables alone with an AUC of 0.868 (95% CI: 0.811-0.917), which was improved by combining with demographic data yielding an AUC 0.895 (95% CI: 0.845-0.939). The algorithm performed well in an independent validation cohort with AUC 0.810 (0.731-0.874). Subjects with higher ML scores (>0.4121) were associated with increased adjusted hazard ratio for a composite outcome than subjects with lower ML scores (1.72, 95% confidence interval 1.09-2.71). Discussion: An ML algorithm using variables derived from clinical CMR is effective in identifying patients with LVDD and providing prognostication for adverse clinical outcomes.

14.
ACS Appl Mater Interfaces ; 16(26): 33371-33378, 2024 Jul 03.
Artículo en Inglés | MEDLINE | ID: mdl-38915181

RESUMEN

Metal-organic frameworks (MOFs) have garnered substantial attention for their unique properties, such as high porosity and tunable structures, making them versatile for various applications. This paper constructs photoactive titanium-organic frameworks by combining Ti(IV) clusters and a bipyridine linker. The MOF is synthesized in situ through imine condensation, resulting in NU-2300. Subsequent ex situ nickel salt complexation results in NU-2300-Ni, which is then used for light-mediated carbon-heteroatom cross-couplings. The photophysical properties of the metallaphotocatalyst were investigated by UV-vis and EPR analyses, and both the Ti cluster and the bipyridine linker were found to contribute to successful catalysis, making it a tandem catalyst. The heterogeneous material retained its performance through five cycles of thioetherification. This work contributes not only to MOF synthetic strategies but also to expanding MOF applications as recyclable, tandem metallaphotocatalysts.

15.
ACS Appl Mater Interfaces ; 16(24): 31798-31806, 2024 Jun 19.
Artículo en Inglés | MEDLINE | ID: mdl-38835166

RESUMEN

Surface barriers are commonly observed in nanoporous materials. Although researchers have explored methods to repair defects or create flawless crystals to mitigate surface barriers, these approaches may not always be practical or readily achievable in targeted metal-organic frameworks (MOFs). In our study, we propose an alternative approach focusing on the introduction of diverse ligands onto a MOF-808 node to finely adjust its adsorption and mass transport characteristics. Significantly, our findings indicate that while adsorption curves can be inferred based on the MOF's chemical composition and the probing molecule, surface permeabilities exhibit variations dependent on the specific probe utilized and the incorporated ligand. Our investigation, considering van der Waals forces exclusively between the adsorbate (e.g., n-hexane, propane, and benzene) and the adsorbent, revealed that augmenting these interactions can indeed improve surface permeation to a certain extent. Conversely, strong adsorption resulting from hydrogen bonding interactions, particularly with water in modified MOFs, led to compromised permeation within the MOF crystals. These outcomes provide valuable insights for the porous materials community and offer guidance in the development of adsorbents with enhanced affinity and superior mass transport properties for gases and vapors.

16.
ACS Appl Mater Interfaces ; 16(24): 31534-31542, 2024 Jun 19.
Artículo en Inglés | MEDLINE | ID: mdl-38856659

RESUMEN

The integration of metal-organic frameworks (MOFs) into composite systems serves as an effective strategy to increase the processability of these materials. Notably, MOF/fiber composites have shown much promise as protective equipment for the capture and remediation of chemical warfare agents. However, the practical application of these composites requires an understanding of their mass transport properties, as both mass transfer resistance at the surface and diffusion within the materials can impact the efficacy of these materials. In this work, we synthesized composite fibers of MOF-808 and amidoxime-functionalized polymers of intrinsic microporosity (PIM-1-AX) and measured the adsorption and mass transport behavior of n-hexane and 2-chloroethyl ethyl sulfide (CEES), a sulfur mustard simulant. We developed a new Fickian diffusion model for cylindrical shapes to fit the dynamic adsorption data obtained from a commercial volumetric adsorption apparatus and found that mass transport behavior in composite fibers closely resembled that in the pure PIM fibers, regardless of MOF loading. Moreover, we found that n-hexane adsorption mirrors that of CEES, indicating that it could be used as a structural mimic for future adsorption studies of the sulfur mustard simulant. These preliminary insights and the new model introduced in this work lay the groundwork for the design of next-generation composite materials for practical applications.

17.
Saudi J Med Med Sci ; 12(2): 175-181, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38764567

RESUMEN

Background: A child safety seat protects children from injury during motor vehicle accidents (MVAs). However, there is a lack of enforcement of regulation regarding its use in Saudi Arabia. Objectives: This study aimed to determine the use of child safety seat and its determinants and barriers in Jeddah, Saudi Arabia. Materials and Methods: This cross-sectional study was based on a structured face-to-face interview across Jeddah among families who drove in cars with children aged ≤5 years. The study used stratified multistage random sampling across the population of the governorate of Jeddah. Results: A total of 675 parents were included, of which 311 (46.1%) reported having a child safety seat in their vehicle, and only 165 (24.4%) reported its regular use. Awareness levels among parents regarding child safety seat use and its benefits, parents' level of education, family size, family income, and the belief in the need for laws governing child safety seat were key determinants of child safety seat use. Poor awareness among parents regarding the utility of child safety seat in reducing child injuries, low education levels among parents, larger families with multiple children, poor affordability, low family income, and a clear lack of laws mandating the use of child safety seat were identified as key barriers. Conclusions: The regular use of child safety seat for children aged ≤5 years is low in even one of the most urban populations of Saudi Arabia. This indicates the need for large-scale awareness drives and stricter implementation of laws enforcing the use of child safety seat in Saudi Arabia.

18.
J Am Chem Soc ; 146(22): 15130-15142, 2024 Jun 05.
Artículo en Inglés | MEDLINE | ID: mdl-38795041

RESUMEN

Investigating the structure-property correlation in porous materials is a fundamental and consistent focus in various scientific domains, especially within sorption research. Metal oxide clusters with capping ligands, characterized by intrinsic cavities formed through specific solid-state packing, demonstrate significant potential as versatile platforms for sorption investigations due to their precisely tunable atomic structures and inherent long-range order. This study presents a series of Ti8Ce2-oxo clusters with subtle variations in coordinated linkers and explores their sorption behavior. Notably, Ti8Ce2-BA (BA denotes benzoic acid) manifests a distinctive two-step profile during the CO2 adsorption, accompanied by a hysteresis loop. This observation marks a new instance within the metal oxide cluster field. Of intrigue, the presence of unsaturated Ce(IV) sites was found to be correlated with the stepped sorption property. Moreover, the introduction of an electrophilic fluorine atom, positioned ortho or para to the benzoic acid, facilitated precise control over gate pressure and stepped sorption quantities. Advanced in situ techniques systematically unraveled the underlying mechanism behind this unique sorption behavior. The findings elucidate that robust Lewis base-acid interactions are established between the CO2 molecules and Ce ions, consequently altering the conformation of coordinated linkers. Conversely, the F atoms primarily contribute to gate pressure variation by influencing the Lewis acidity of the Ce sites. This research advances the understanding in fabricating metal-oxo clusters with structural flexibility and provides profound insights into their host-guest interaction motifs. These insights hold substantial promise across diverse fields and offer valuable guidance for future adsorbent designs grounded in fundamental theories of structure-property relationships.

19.
ACS Appl Mater Interfaces ; 16(23): 30020-30030, 2024 Jun 12.
Artículo en Inglés | MEDLINE | ID: mdl-38814279

RESUMEN

Titanium-oxo clusters, with their robust structure and suitable optical and electronic properties, have been widely investigated as photocatalysts. Heterometallic Ti/M-oxo clusters provide additional tunability and functionality, which enable systematic structure-activity investigations to elucidate the reaction mechanisms and improve the catalyst design. Incorporating cerium into Ti-oxo clusters can provide additional redox (CeIV/CeIII) and oxygen harvesting ability, but to date, only a limited number of structurally defined titanium-cerium (Ti/Ce) clusters have been reported due to their synthetic challenges. Herein, we report the synthesis and photocatalytic properties of two structurally defined Ti/Ce-oxo clusters, Ti8Ce2(BA)16 and Ti9Ce4(BA)20, as well as a TiCe-BA cluster with a calculated formula of Ti20Ce9O36(BA)42. Photocatalytic study of these clusters demonstrates that the amount of Ce3+ species greatly impacts its photocatalytic oxidation performance, and their superior photocatalytic reactivity toward aerobic alcohol oxidation can be contributed to the synergistic effects of the multiple radical species generated upon light absorption. This work represents a significant milestone in the construction of stable Ti/Ce-oxo clusters, enriching the current library of known heterometallic Ti/M-oxo clusters, and providing a series of crystalline materials with great promise of photoluminescence and photovoltaic chemistry.

20.
Science ; 384(6695): 540-546, 2024 May 03.
Artículo en Inglés | MEDLINE | ID: mdl-38696554

RESUMEN

Although technologically promising, the reduction of carbon dioxide (CO2) to produce carbon monoxide (CO) remains economically challenging owing to the lack of an inexpensive, active, highly selective, and stable catalyst. We show that nanocrystalline cubic molybdenum carbide (α-Mo2C), prepared through a facile and scalable route, offers 100% selectivity for CO2 reduction to CO while maintaining its initial equilibrium conversion at high space velocity after more than 500 hours of exposure to harsh reaction conditions at 600°C. The combination of operando and postreaction characterization of the catalyst revealed that its high activity, selectivity, and stability are attributable to crystallographic phase purity, weak CO-Mo2C interactions, and interstitial oxygen atoms, respectively. Mechanistic studies and density functional theory (DFT) calculations provided evidence that the reaction proceeds through an H2-aided redox mechanism.

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