RESUMO
Demands for green ammonia production increase due to its application as a proton carrier, and recent achievements in electrochemical Li-mediated nitrogen reduction reactions (Li-NRRs) show promising reliability. Here, it is demonstrated that F-containing additives in the electrolyte improve ammonia production by modulating the solid electrolyte interphase (SEI). It is suggested that the anionic additives with low lowest unoccupied molecular orbital levels enhance efficiency by contributing to the formation of a conductive SEI incorporated with LiF. Specifically, as little as 0.3 wt.% of BF4 - additive to the electrolyte, the Faradaic efficiency (FE) for ammonia production is enhanced by over 15% compared to an additive-free electrolyte, achieving a high yield of 161 ± 3 nmol s-1 cm-2. The BF4 - additive exhibits advantages, with decreased overpotential and improved FE, compared to its use as the bulk electrolyte. The observation of the Li3N upper layer implies that active Li-NRR catalytic cycles are occurring on the outermost SEI, and density functional theory simulations propose that an SEI incorporated with LiF facilitates energy profiles for the protonation by adjusting the binding energies of the intermediates compared to bare copper. This study unlocks the potential of additives and offers insights into the SEIs for efficient Li-NRRs.
RESUMO
The introduction of non-metal elements including boron has been identified as a significant means to enhance oxygen evolution reaction (OER) performance in NiFe-based catalysts. To understand the catalytic activity and stability, recent attention has widened toward the Fe species as a potential contributor, prompting exploration from various perspectives. Here, boron incorporation in NiFe hydroxide achieves significantly enhanced activity and stability compared to the boron-free NiFe hydroxide. The boron inclusion in NiFe hydroxide is found to show exceptionally improved stability from 12 to 100 hours at a high current density (200 mA cm-2). It facilitates the production and redeposition of OER-active, high-valent Fe species in NiFe hydroxide based on the operando Raman, UV-vis, and X-ray absorption spectroscopy analysis. It is proposed that preserving a homogenous distribution of Fe across the boron-containing catalyst surface enhances OER stability, unlike the bare NiFe hydroxide electrocatalyst, which exhibits uneven Fe dissolution, confirmed through elementary mapping analysis. These findings shed light on the potential of anionic regulation to augment the activity of iron, an aspect not previously explored in depth, and thus are expected to aid in designing practical OER electrocatalysts.
RESUMO
The mi-iuy croaker Miichthys miiuy has immense commercial value in the Republic of Korea. The red drum Sciaenops ocellatus is widely produced by aquaculture, although its price is approximately 25% that of M. miiuy. S. ocellatus has black spots on its tail, enabling it to be distinguished from M. miiuy based on appearance. However, identifying S. ocellatus after simple processing steps, such as skin removal and dicing, is difficult. Certain traders misrepresent and sell S. ocellatus as M. miiuy or cultured M. miiuy for illegal economical gain. Therefore, an accurate and rapid identification method is required to distinguish between M. miiuy and S. ocellatus in the field. Here, a method for rapid field identification was developed based on species-specific primers using a portable ultra-fast PCR instrument. The ultra-fast real-time PCR method can complete the entire analytical procedure, including DNA isolation, amplification, and detection, within 30 min, thus maintaining the accuracy of identifying M. miiuy and S. ocellatus products on site. Forty-nine commercial products were tested, and all samples were successfully identified. Thus, the developed method is rapid, efficient tool for ensuring consumer protection. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10068-021-00954-4.