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The direct liquid-phase oxidative carbonylation of methane, utilizing abundant natural gas, offers a mild and straightforward alternative. However, most catalysts proposed for this process suffer from low acetic acid yields due to few active sites and rapid C1 oxygenate generation, impeding their industrial feasibility. Herein, we report a highly efficient 0.1Cu/Fe-HZSM-5-TF (TF denotes template-free synthesis) catalyst featuring exclusively mononuclear Fe and Cu anchored in the ZSM-5 channels. Under optimized conditions, the catalyst achieved an unprecedented acetic acid yield of 40.5â mmol gcat -1 h-1 at 50 °C, tripling the previous records of 12.0â mmol gcat -1 h-1. Comprehensive characterization, isotope-labeled experiments and density functional theory (DFT) calculations reveal that the homogeneous mononuclear Fe sites are responsible for the activation and oxidation of methane, while the neighboring Cu sites play a key role in retarding the oxidation process, promoting C-C coupling for effective acetic acid synthesis. Furthermore, the methyl-group carbon in acetic acid originates solely from methane, while its carbonyl-group carbon is derived exclusively from CO, rather than the conversion of other C1 oxygenates. The proposed bimetallic catalyst design not only overcomes the limitations of current catalysts but also generalizes the oxidative carbonylation of other alkanes, demonstrating promising advancements in sustainable chemical synthesis.
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The selective oxidation of CH4 in the aqueous phase to produce valuable chemicals has attracted considerable attention due to its mild reaction conditions and simple process. As the most widely studied catalyst for this reaction, Fe-ZSM-5 demonstrates high intrinsic activity and selectivity; however, Fe-ZSM-5 prepared using conventional methods has a limited number of active Fe sites, resulting in low CH4 conversion per unit mass of the catalyst. This study reports a facile organic-template-free synthesis strategy that enables the incorporation of more Fe into the zeolite framework with a higher dispersion degree compared to conventional synthesis methods. Because framework Fe incorporated in this way is more readily transformed into isolated extra-framework Fe species under thermal treatment, the overall effect is that Fe-ZSM-5 prepared using this method (Fe-HZ5-TF) has 3 times as many catalytically active sites as conventional Fe-ZSM-5. When used for the selective oxidation of CH4 with 0.5 M H2O2 at 75 °C, Fe-HZ5-TF produced a high C1 oxygenate yield of 109.4 mmol gcat-1 h-1 (a HCOOH selectivity of 91.1%), surpassing other catalysts reported to date. Spectroscopic characterization and density functional theory calculations revealed that the active sites in Fe-HZ5-TF are mononuclear Fe species in the form of [(H2O)3Fe(IV)âO]2+ bound to Al pairs in the zeolite framework. This differs from conventional Fe-ZSM-5, where binuclear Fe acts as the active site. Analysis of the catalyst and product evolution during the reaction suggests a radical-driven pathway to explain CH4 activation at the mononuclear Fe site and subsequent conversion to C1 oxygenates.
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Zeolite-supported nickel (Ni) catalysts have been extensively studied for the dry reforming of methane (DRM). It is generally believed that prior to or during the reaction, Ni is reduced to a metallic state to act as the catalytic site. Here, we employed a ligand-protected synthesis method to achieve a high degree of Ni incorporation into the framework of the MFI zeolite. The incorporated Ni species retained their cationic nature during the DRM reaction carried out at 600 °C, exhibiting higher apparent catalytic activity and significantly greater catalytic stability in comparison to supported metallic Ni particles at the same loading. From theoretical and experimental evidence, we conclude that the incorporation of Ni into the zeolite framework leads to the formation of metal-oxygen (Niδ+-O(2-ξ)-) pairs, which serve as catalytic active sites, promoting the dissociation of C-H bonds in CH4 through a mechanism distinct from that of metallic Ni. The conversion of CH4 on cationic Ni single sites follows the CHx oxidation pathway, which is characterized by the rapid transformation of partial cracking intermediates CHx*, effectively inhibiting coke formation. The presence of the CHx oxidation pathway was experimentally validated by identifying the reaction intermediates. These new mechanistic insights elucidate the exceptional performance of the developed Ni-MFI catalyst and offer guidance for designing more efficient and stable Ni-based DRM catalysts.
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Given that ethanol can be obtained from abundant biomass resources (e.g., crops, sugarcane, cellulose, and algae), waste, and CO2, its conversion into value-added chemicals holds promise for the sustainable production of high-demand chemical commodities. Nonoxygenated chemicals, including light olefins, 1,3-butadiene, aromatics, and gasoline, are some of the most important of these commodities, substantially contributing to modern lifestyles. Despite the industrial implementation of some ethanol-to-hydrocarbons processes, several fundamental questions and technological challenges remain unaddressed. In addition, the utilization of ethanol as an intermediate provides new opportunities for the direct valorization of CO and CO2. Herein, the recent advances in the design of ethanol conversion catalysts are summarized, providing mechanistic insights into the corresponding reactions and catalyst deactivation, and discussing the related future research directions, including the exploitation of active site proximity to achieve better synergistic effects for reactions involving ethanol.
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Metal-organic frameworks have drawn attention as potential catalysts owing to their unique tunable surface chemistry and accessibility. However, their application in thermal catalysis has been limited because of their instability under harsh temperatures and pressures, such as the hydrogenation of CO2 to methanol. Herein, we use a controlled two-step method to synthesize finely dispersed Cu on a zeolitic imidazolate framework-8 (ZIF-8). This catalyst suffers a series of transformations during the CO2 hydrogenation to methanol, leading to ~14 nm Cu nanoparticles encapsulated on the Zn-based MOF that are highly active (2-fold higher methanol productivity than the commercial Cu-Zn-Al catalyst), very selective (>90%), and remarkably stable for over 150 h. In situ spectroscopy, density functional theory calculations, and kinetic results reveal the preferential adsorption sites, the preferential reaction pathways, and the reverse water gas shift reaction suppression over this catalyst. The developed material is robust, easy to synthesize, and active for CO2 utilization.
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Seeking and understanding patients' values and preferences is one of the essential elements in shared decision making, which is associated with treatment adherence in psychiatry. However, negotiating treatment in psychiatric contexts can be challenging with patients whose ability to evaluate treatment recommendations rationally may be impaired. This article attempts to examine a conversational practice that psychiatrists use to deal with patients' views and perspectives by formulating what the patients have said related to treatment. Taking the naturally occurring, face-to-face outpatient psychiatric consultations as the data, the present study uses conversation analysis (CA) as a method to demonstrate in a fine-grained detail what functions formulations of patients' perspectives serve in psychiatric contexts. We found that by eliciting patients' views and perspectives toward treatment, this type of formulation is not only used to achieve mutual understanding and establish the grounds for treatment decisions, but may also be used to challenge the legitimacy of patients' position, steering treatment decision to the direction preferred by the psychiatrists. We argue that in the process of treatment decision making, psychiatrists do not simply impose their perspectives upon the patients, instead, they attempt to achieve consensus with patients by balancing their institutional authority and orientation to the patients' perspectives. Data are in Chinese with English translation.
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The experience of loss of agency is one of the reasons for clients to go for psychotherapy. Enhancing clients' agency has been considered a fundamental factor for successful treatment in psychiatry and psychotherapy, yet few studies have investigated the interactional realization of how therapists do this in authentic psychotherapeutic encounters. Drawing on audio-recorded talk-in-interaction between clients and psychotherapists in cognitive behavioral therapy (CBT) encounters at a mental health center in China, this paper uses the method of conversation analysis to demonstrate how therapists ascribe agency positions to clients by issuing formulations of what the clients have just said. Two types of formulation were identified: affirmative formulations and challenging formulations. In the first type, the therapists highlight the positive aspect of the clients' description of their experiences and ascribe an agentic position to the clients. In the second, the therapists challenge the clients' implausible views and their non-agentic positioning of themselves. This study shows that the therapists' formulation could be employed to manage the epistemic difficulties associated with claiming knowledge about the clients' inner states and assessing their feelings. In this sense, the formulation is a robust interactional device in negotiating epistemic problems in addressing the clients' experiences and promoting their agency in therapy. However, it is noteworthy that in the challenging formulation, therapists claim privileged access to the clients' knowledge domain and challenge their prior epistemic status, which might run the risk of engendering clients' resistance.
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A highly active anode material for solid oxide fuel cells resistant to carbon deposition is developed. Co-Fe co-doped La0.5Ba0.5MnO3-δ with a cubic-hexagonal heterogeneous stucture is synthesized through the Pechini method. An A-site ordered double perovskite with Co0.94Fe0.06 alloy-oxide core-shell nanoparticles on its surface is formed after reduction. The phase transition and the exsolution of the nanoparticles are investigated with X-ray diffraction, thermogravimetric analysis, and high-resolution transmission electron microscope. The exsolved nanoparticles with the layered double-perovskite supporter show a high catalytic activity. A single cell with that anode and a 300 µm thick La0.8Sr0.2Ga0.8Mg0.2O3-δ electrolyte layer exhibits maximum power densities of 1479 and 503 mW cm-2 at 850 °C with wet hydrogen and wet methane fuels, respectively. Moreover, the single cell fed with wet methane exhibits a stable power output at 850 °C for 200 h, demonstrating a high resistance to carbon deposition of the anode due to the strong anchor of the exsolved nanoparticles on the perovskite parent. The oxide shell also preserves the metal particles from coking.
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BACKGROUND: Terminally ill patients can benefit from palliative care, including relief from physical and emotional suffering, improved quality of life, and longer survival rates. However, despite marked development in other countries, palliative care is still in its infancy in China. OBJECTIVES: The general population and healthcare professionals in China have yet to realize the importance of palliative care services. This article describes the status of palliative care services in China, the historic development of palliative care, and the barriers to its advancement. METHODS: The status quo of hospice and palliative care in China is reviewed, and suggestions are provided on how nurses can improve their abilities to care for patients with cancer at the end of life. FINDINGS: A significant amount of work is needed in China to meet the standards of international palliative care societies. Palliative care training for nurses is still very limited. Nurses and other health providers who are engaged in palliative care should be well trained regarding the principles and procedures of palliative care to ensure quality care.
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Hospitais para Doentes Terminais/organização & administração , Cuidados Paliativos/organização & administração , China , Previsões , Necessidades e Demandas de Serviços de Saúde , Cuidados Paliativos/tendênciasRESUMO
OBJECTIVE: To build a type 2 diabetes mellitus rat model with cardiac ischemia. METHODS: Male Wistar rats were fed high sucrose and high fat diet for four weeks and then injected with streptozoticin (STZ) (40 mg/kg .i.p.). The levels of fasting blood glucose and serum insulin were monitored every week. The body weights of rats were also measured every week. The blood levels of creatine kinase and lactate dehydrogenase (LDH) were measured following the electrocardiograph used BL-410 biological experiment system. RESULTS: The serum insulin levels of diabetic rats were 4.05 ng/ml after four weeks high sucrose and high fat diet. The fasting blood glucose levels of diabetic rats were 17.9 mmol/L after injection. Compared with normal group, there was obvious change of S-T segment in the electrocardiograph of diabetic group at the fourteenth week. The levels of creatine kinase and lactate dehydrogenase in diabetic group significantly increased in comparison with those in normal group. CONCLUSION: The cardiac ischemia of diabetic rats model is suitable for investigating cardiac disease of diabetes mellitus.