In this study, we have developed a method to predict the steady-state rate and Cu oxidation state during ethylene oxychlorination from a reaction rate diagram of the individual steps involved in the catalytic oxychlorination cycle. The steady state of the redox cycle is represented by a cross point of the reaction rates of the reduction and oxidation steps as a function of the Cu2+ in the rate diagram. Transient kinetics of elementary reactions and steady-state kinetics of the overall catalytic cycle were investigated in an operando study using combined mass and UV–vis-NIR spectrophotometry. The catalytic consequence of the promoters was then evaluated in terms of reduction and oxidation activity as well as number of active sites, site activity, and the catalyst oxidation state at steady state. Results revealed that the neat CuCl2 catalysts operated at low Cu2+ at the steady-state conditions with stoichiometric feed composition, as a result of relatively low oxidation rate of Cu1+. As a consequence of a high content of Cu1+, ethylene conversion and selectivity are low, and the catalyst deactivates rapidly. By the promotion of the CuCl2 catalyst by K, the reactor operates at a high Cu2+ concentration with much improved stability as a result of enhanced oxidation rate, but the catalyst has low activity due to significantly reduced reduction rate. Therefore, the rate diagram has been applied as a tool for a rational design of the CuCl2-based oxychlorination catalysts, and Ce was proposed as the promoter due to its high promotion to the oxidation and low reactivity with Cu ions. It was found that the activity of the Ce-promoted catalysts increased 8 times compared to the neat CuCl2 catalyst and moreover significantly improved the stability for the oxychlorination catalyst at steady state, due to the enhancement of both the rates of the reduction and oxidation. It is anticipated that the methodology developed here paves the way for a general method for catalyst design of heterogeneous catalysts where the catalyst undergoes oxidation state changes, in particular in redox reactions.
Nurses need to be resilient to be able to endure their working conditions, and their moral courage can affect their resilience. This work aimed at studying the relationship between resilience and professional moral courage among nurses working in hospitals. This descriptive cross-sectional study was conducted on 375 nurses working in teaching hospitals in the city of Ardabil in Iran in 2019. Data was collected using the following questionnaires: a demographic questionnaire, Sekerka et al. Moral Courage Scale and Davidson-Connor Resilience Scale. The reliability of the Davidson-Connor Resilience Scale, and Moral Courage Scale were found to be 89% and 85% using the test-retest method. The data were analyzed by Pearson correlation coefficient, t-test, variance analysis, and linear regression using the SPSS software version 24. In participating nurses, mean scores were 6.35±0.5 for total moral courage (favorable) and 79.35±0.35 (moderate) for resilience, respectively. A positive and significant relationship was observed between resilience and professional moral courage (P<0.05, r=0.1). Given the positive and significant relationship between resilience and professional moral courage, nurses require to have the high moral courage to enhance their resilience. Determining factors affecting moral courage and resilience, as well as finding strategies and creating an appropriate moral climate can increase nurses' morally courageous behaviors and resilience.
The energy transition is the pathway to transform the global economy away from its current dependence on fossil fuels towards net zero carbon emissions. This requires the rapid and large-scale deployment of renewable energy. However, most renewables, such as wind and solar, are intermittent and hence generation and demand do not necessarily match. One way to overcome this problem is to use excess renewable power to generate hydrogen by electrolysis, which is used as an energy store, and then consumed in fuel cells, or burnt in generators and boilers on demand, much as is presently done with natural gas, but with zero emissions. Using hydrogen in this way necessitates large-scale storage: the most practical manner to do this is deep underground in salt caverns, or porous rock, as currently implemented for natural gas and carbon dioxide. This paper reviews the concepts, and challenges of underground hydrogen storage. As well as summarizing the state-of-theart, with reference to current and proposed storage projects, suggestions are made for future work and gaps in our current understanding are highlighted. The role of hydrogen in the energy transition and storage methods are described in detail. Hydrogen flow and its fate in the subsurface are reviewed, emphasizing the unique challenges compared to other types of gas storage. In addition, site selection criteria are considered in the light of current field experience.
C(3) or C(3v) symmetric enantiopure syn-tris(norborneno)benzenes with various functional groups were synthesized through Pd-catalyzed cyclotrimerization of enantiopure iodonorbornenes. The generality of Pd-catalyzed cyclotrimerization for syn-tris(norborneno)benzenes were well-demonstrated.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.