This review analyzes the structural factors that impact Pt utilization in PEMFCs in great detail, emphasizing the mechanistic and molecule-level insights.
Factors related to bulk cargo port scheduling are very complex and peculiar. Changes in the factors will affect the reusability of a model, so establishing a reliable scheduling model for bulk cargo ports is particularly important. This paper sorts the factors affecting bulk cargo port scheduling, such as the number of vessels, the number of berths, vessel-berthing constraints (basic factors), the service priority, and the makespan (special factors), and then establishes the non-deterministic polynomial (NP) model, which aims to minimize the total service time and makespan. Lastly, it solves the model based on the multi-phase particle swarm optimization (MPPSO) algorithm and Matlab. Some important conclusions are obtained. (1) For the model neglecting priority, the total service time is the smallest, whereas the maximum waiting time and maximum operating time are relatively large, and the makespan is the latest. (2) For the model considering priority, the total service time is relatively large, whereas the maximum waiting time and maximum operating time are relatively small, and the makespan is relatively early. (3) For the model considering the makespan, the total service time is the mostlargest, whereas the maximum waiting time and especially the maximum operating time are the smallest, and the makespan is the earliest. We can choose different models according to different situations in bulk cargo port scheduling.
The increasing demand for portable and wearable electronics requires lightweight, thin, and highly flexible power sources, for example, flexible zinc‐air batteries (ZABs). The so‐far reported flexible ZAB devices mostly remain bulky, with a design consisting of two relatively thick substrates (e.g., carbon cloths and/or metal foams) and a gel electrolyte‐coated separator in between. Herein, an ultrathin (≈0.2 mm) solid‐state ZAB with high flexibility and performance is introduced by directly forming self‐standing active layers on each surface of an alkaline polymer membrane through an ink‐casting/hot‐pressing approach. A Fe/N‐doped 3D carbon with hierarchic pores and an interconnected network structure is used as cathode electrocatalyst, so that the backing gas‐diffusion layer (e.g., carbon cloth) can be abandoned. What is further, a microstructure‐modulating method to significantly increase the FeN4 active sites for oxygen reduction reaction is developed, thus significantly boosting the performance of the ZAB. The assembled solid‐state ZAB manifests remarkable peak power density of 250 mW cm−3 and high capacity of 150.4 mAh cm−3 at 8.3 mA cm−3, as well as excellent flexibility. The new design should provide valuable opportunity to the portable and wearable electronics.
The Co−Mn spinel oxides have attracted much research attention as a class of low-cost electrocatalysts toward the oxygen reduction reaction (ORR) owing to their promising performance in anion-exchange membrane fuel cells (AEMFCs). In this work, the nature of the active sites in a representative CoMn 2 O 4 catalyst was investigated with the assistance of in situ X-ray absorption spectroscopy (XAS) within the ORR-relevant potential range. Our work revealed that the superior activity of the Co−Mn spinel oxides relates to the Mn 2+ /Mn 3+ redox transition. The Mn 2+ /Mn 3+ -associated activity is largely affected by the operating potential window, i.e., an activity loss would be observed for Co−Mn spinel oxides operated at potential lower than 0.4 V (vs RHE). It is proposed that this irreversible activity decay is caused by the irreversible change of the Jahn−Teller (J−T) distortion during the Mn 2+ /Mn 3+ transition.
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