Recent measurements of the temperature profile across the interface of an evaporating liquid are in strong disagreement with the predictions from classical kinetic theory or nonequilibrium thermodynamics. However, these previous measurements in the vapor were made within a minimum of 27 mean free paths of the interface. Since classical kinetic theory indicates that sharp changes in the temperature can occur near the interface of an evaporating liquid, a series of experiments were performed to determine if the disagreement could be resolved by measurements of the temperature closer to the interface. The measurements reported herein were performed as close as one mean free path of the interface of an evaporating liquid. The results indicate that it is the higher-energy molecules that escape the liquid during evaporation. Their temperature is greater than that in the liquid phase at the interface and as a result there is a discontinuity in temperature across the interface that is much larger in magnitude ͑up to 7.8°C in our experiments͒ and in the opposite direction to that predicted by classical kinetic theory or nonequilibrium thermodynamics. The measurements reported herein support the previous ones.
Recent measurements of the conditions existing at the interface of an evaporating liquid have found that the temperature approximately one mean free path from the interface in the vapor was higher than the temperature of the liquid at the interface. The measured temperature discontinuity at the interface is in the opposite direction of that predicted by several recent studies based on classical kinetic theory. A theoretical approach based on the transition probability concept of quantum mechanics, called statistical rate theory ͑SRT͒, is used herein to develop an expression for predicting the evaporation flux. The expression obtained is free of any fitting parameters. When applied to predict the conditions at which a particular value of the evaporation flux is expected and the result compared with the measurements at 15 different experimental conditions, it is found that the SRT expression accurately predicts the conditions.
A general dealloying strategy is developed to prepare multi-component alloys with high thermal stability, electrochemical durability, and catalytic activity.
Developing highly efficient catalysts for oxygen evolution reactions (OER) is a key step for rechargeable metal− oxygen batteries and water splitting. Usually, binary NiFe or ternary NiCoFe nano-alloys are used as the OER catalysts. Herein, combining the precursor alloy design with chemical etching, a simple dealloying route is developed to controllably incorporate five or more nonprecious metals into one nanostructured alloy with a naturally oxidized surface, that is, nanoporous high entropy alloys (np-HEAs) covered with high-entropy (oxy)hydroxides (HEOs). It is found that the alloy composition plays a dominant role in the OER activity enhancement with the np-AlNiCoFeX (X = Mo, Nb, Cr) combination showing the highest activity. Forming quinary HEAs also greatly enhances the electrochemical cycling stabilities compared with the ternary and quaternary counterparts. The result indicates the significance of synergistically incorporating five or more metal elements in one single-phase nanostructure, which provides more structural and chemical degrees of freedom to boost the catalytic performance, overcoming the restriction of normal binary or ternary alloys. Multinary transition metal-based np-HEA is a new class of promising catalyst for various important reactions.
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.