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Rask Harder posted an update 3 weeks, 2 days ago
To well address the problem of low stability for Ru-based catalysts against sintering and leaching during synthesis and aqueous levulinic acid (LA) hydrogenation to γ-valerolactone (GVL), herein we demonstrate an “inside-to-outside” synthetic strategy for robust yolk-structured nanospheres within a single Ru nanoparticle (NP, 4.2 nm) anchored inside the mesoporous shell (pore size, 4.0 nm), denoted as YS Ru@HMCS (yolk-structured Ru encapsulated into hollow mesoporous carbon sphere). Such a shell-supported-core configuration combines the merits of conventional yolk-structured and supported types, in which the active core is not only fully exposed, but also strongly anchored on the shell, based on the optimized interaction between oxidized Ru NP and N-doped mesoporous carbon shell. As a consequence, the resultant YS Ru@HMCS, delivers a high LA conversion (99.4%), a large selectivity to GVL (99.9%), and prolonged cycling life (up to 9 cycles) under water towards the LA hydrogenation, that exceeds conventional yolk-structured and supported analogues. Sintering-resistant, a single Ru NP is successfully encapsulated, and its leaching-resistant property is enhanced based on the improved metal-support contact, thus affording a highly stable Ru catalyst. Moreover, such a synthetic concept can be extended to the stabilization of other supported catalysts, providing a general approach to enhancing both the thermal and chemical stability of supported nanocatalysts.p-xylene is a harmful volatile organic compound that needs to be tested for indoor air quality detection. We report on the sensing characteristics of CuO and Zn doped CuO nanoplatelets of various concentrations that were prepared by hydrothermal synthesis, against nine different gases. These CuO and Zn based nanoplatelets were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, photoluminescence emission and vibrating sample magnetometer measurements. CuO and 0.1 at. % Zn doped CuO samples were most sensitive and selective to p-xylene gas with relatively high responses (Ra/Rg ratio) of about 42 and 53 at an operating temperature of 150 °C, respectively. These responses were about six times higher compared to the other 8 tested interfering gases. All these samples further exhibited a paramagnetic behaviour at room temperature, due to small traces of point defects, such as oxygen vacancies. Both these sensor materials did not show green luminescence at room temperature that is normally associated with oxygen vacancies. However, temperature dependent photoluminescence (PL) measurements for the 0.1 at. % Zn doped CuO showed broad visible emission, including green luminescence, which increased with temperature up to 150 °C and coincided with the gas sensing temperature. The pure CuO, however, showed a rapid quenching in PL emission with an increase in the temperature up to 150 °C. Nevertheless, both pure CuO and 0.1 at. % Zn doped CuO based sensors were highly sensitive to the p-xylene gas. The mechanism associated to the xylene superior sensing was considered in terms of point defects and surface area as active sites for adsorption of gas molecules.Two new 7-N,N’-dialkylaminomethyl-8-Hydroxyquinolines, namely 7-N,N’-dipropylaminomethyl-8-Hydroxyquinoline (DPQ) and 7-N,N’-dimethylaminomethyl-8-Hydroxyquinoline (DMQ), were synthesized and characterized using 1H/13C NMR and Elemental analysis methods. selleck compound Corrosion inhibition effect of DMP and DPQ for C40E steel in 1 M HCl was evaluated at different concentrations (10-3 to 10-6M) and temperatures (298 to 328 K) using several experimental and computational approaches. Weight loss and electrochemical studies showed that protection efficiencies (ηmax) of DPQ and DMQ increase with increase in concentrations. The DPQ and DMQ showed maximum efficiencies of 96.1% and 94.4%, respectivelyat 10-3 M. Polarization measurements showed that DMQ and DPQ act as mixed type corrosion inhibitors. Adsorption of DPQ and DMQ on C40E steel in 1 M HCl obeyed the Langmuir adsorption isotherm. Variation in surface morphology of corroded metallic surface with and without DMQ and DPQ was demonstrated using scanning electron microscopy. Molecular dynamics (MD) simulations studies showed that DPQ and DMQ acquire the flat or horizontal orientation over the C40E steel. DFT analyses revealed that both DPQ and DMQ interact with the C40E steelusing electron-sharing(donor-acceptor)mechanism. Computational analyses conducted using DFT and MD simulations well corroborate the experimental results.A key objective of an emergency call for cardiac arrest is to recruit a bystander to perform cardio-pulmonary resuscitation (CPR) until the ambulance arrives. Emergency medical services worldwide work towards increasing the rate of bystander-CPR, and existing research has identified a number of physical barriers to the provision of bystander-CPR. Yet, little is known about the specific ways in which emergency callers resist recruitment to perform basic first-aid, sometimes in the absence of any physical obstacle. This study investigated 65 emergency calls for cardiac arrest received in Australia in 2014 and 2015, in which the callers initially resisted CPR. We used conversation analysis to examine callers’ practices to resist recruitment and call-takers’ practices to counter this resistance. We found that callers who resisted CPR typically provided an account. When callers accounted for their resistance on deontic grounds, they expressed that CPR was not a possible course of action (e.g. “I can’t do it”). When callers provided an epistemic account, their justification was based on their knowledge or opinion (e.g. “I think it’s too late”). Our findings suggest that epistemic resistance can be a barrier to bystander-CPR. We identified two practices used by call-takers to address caller resistance based on epistemics. Providing more context on the purpose of CPR (e.g. “this is to help him in the meantime”) seemed effective in persuading callers to perform CPR. By contrast, aligning with the caller’s epistemic and deontic rights (e.g. “it’s up to you”) did not seem effective in persuading callers.