Search

Zinc manganese oxide (ZnMn2O4), exhibiting a clustered spherical structure, is synthesized using a low-temperature coprecipitation method. Following this, a coating of nano-sized Al2O3 is applied via a wet chemical technique. The resultant materials—designated as ZnMn2O4 (ZMO) and Al2O3—coated ZnMn2O4 (ZMO-AlO)-undergo characterization using X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. Scanning electron microscopy reveals that both ZMO and ZMO-AlO retain their clustered spherical morphologies. Furthermore, XPS and TEM confirm the presence of an Al2O3 layer on the ZMO-AlO sample. In terms of electrochemical performance, a significant improvement is observed. Specifically, the Al2O3 coating enhances the initial discharge capacity of ZMO-AlO to 1228 mAh·g−1, compared to the 1140 mAh·g−1 capacity of the unmodified ZMO material. During the second charging and discharging cycle, the ZMO-AlO samples demonstrate specific capacities of 763 and 788 mAh·g−1, respectively, achieving a coulombic efficiency of 96.8%. By contrast, the ZMO samples show specific capacities of 760 and 715 mAh·g−1, respectively, with a slightly lower coulombic efficiency of 94.1%. When evaluating the electrochemical lithium storage performance of ZMO and ZMO-AlO at a current density of 100 mA·g−1, it becomes evident that the Al2O3-modified ZnMn2O4 (ZMO-AlO) offers superior performance compared to the unmodified ZMO. [ABSTRACT FROM AUTHOR]

Ionic liquids have excellent physical and chemical properties, enabling them to be widely used in electrochemical oxygen sensors. In recent years, the preparation of modified materials and ionic liquids mixed to improve the oxygen sensitivity of sensors has become a hotspot. In this study, 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6), which is a liquid at room temperature, was successfully prepared by a simple one-pot method, and BMIMPF6 reacts at different oxygen concentrations. Bamboo-like carbon nanotube (BCNT) composites containing cobalt nanoparticles derived from graphite phase carbon nitride (g-C3N4) were prepared and fully mixed with the ionic liquid to form the BCNT/Co + BMIMPF6 composite. The electrochemical behavior of oxygen in the electrochemical sensor was studied. The results show that the response current and stability of the oxygen sensor based on the BCNT/Co + BMIMPF6 composite are significantly improved, the sensitivity is 1.15 μA/[%O2], the response time is 16 s, and the linearity is good. [ABSTRACT FROM AUTHOR]

With the continuous development of the maritime transportation industry, many researchers paid highly attention to the research field of maritime transportation, and numerous related studies were conducted. Therefore, it is very timely and necessary to examine the active authors, affiliations and nationalities focused on this research field, so as to enable new researchers to quickly build an understanding of this field. Based on 2,972 papers published in 66 journals from 2011 to 2020, this paper uses three indicators: number of papers, the weighted score, and the impact score, to rank top fifty authors, affiliations, and nationalities in the research field of maritime transportation, and show their ranking changes in five-year intervals. Finally, this paper counts the frequency of keywords from all papers and surveys the number of research topics in the past ten years from the four research fields of 'shipping' 'port' 'maritime fleet' and 'green shipping' to help researchers identify research hotspots and grasp future directions. [ABSTRACT FROM AUTHOR]