RESUMEN
The pursuit of stable and efficient electrocatalysts toward seawater oxidation is of great interest, yet it poses considerable challenges. Herein, the utilization of Cr-doped CoFe-layered double hydroxide nanosheet array is reported on nickel-foam (Cr-CoFe-LDH/NF) as an efficient electrocatalyst for oxygen evolution reaction in alkaline seawater. The Cr-CoFe-LDH/NF catalyst can achieve current densities of 500 and 1000 mA cm -2 with remarkably low overpotentials of only 334 and 369 mV, respectively. Furthermore, it maintains at least 100 h stability when operated at 500 mA cm-2.
RESUMEN
Electrochemical CO2 reduction into value-added chemicals represents an attractive and promising approach to capitalize on the abundant CO2 present in the atmosphere. This reaction, however, is hampered by low energy efficiency and selectivity owing to competition from hydrogen evolution reaction and multiple-electron transfer processes. Therefore, there is a pressing need to develop efficient yet cost-effective electrocatalysts to facilitate practical applications. Sn-based electrocatalysts have gained increasing attention in this active field due to their outstanding merits such as abundance, non-toxicity, and environmental friendliness. This review provides a comprehensive overview of recent advances in Sn-based catalysts for the CO2 reduction reaction (CO2RR), beginning with a brief introduction to the CO2RR mechanism. Subsequently, the CO2RR performance of various Sn-based catalysts with different structures is discussed. The article concludes by addressing the existing challenges and offering personal perspectives on the future prospects in this exciting research area.
RESUMEN
Chemical functionalization of silicon oxide (SiO(2)) surfaces with silane molecules is an important technique for a variety of device and sensor applications. Quality control of self-assembled monolayers (SAMs) is difficult to achieve because of the lack of a direct measure for newly formed interfacial Si-O bonds. Herein we report a sensitive measure of the bonding interface between the SAM and SiO(2), whereby the longitudinal optical (LO) phonon mode of SiO(2) provides a high level of selectivity for the characterization of newly formed interfacial bonds. The intensity and spectral position of the LO peak, observed upon silanization of a variety of silane molecules, are shown to be reliable fingerprints of formation of interfacial bonds that effectively extend the Si-O network after SAM formation. While the IR absorption intensities of functional groups (e.g., >C=O, CH(2)/CH(3)) depend on the nature of the films, the blue-shift and intensity increase of the LO phonon mode are common to all silane molecules investigated and their magnitude is associated with the creation of interfacial bonds only. Moreover, results from this study demonstrate the ability of the LO phonon mode to analyze the silanization kinetics of SiO(2) surfaces, which provides mechanistic insights on the self-assembly process to help achieve a stable and high quality SAM.
RESUMEN
Control of polymer morphology and chain orientation is of great importance in organic solar cells and field effect transistors (OFETs). Here we report the use of nanoimprint lithography to fabricate large-area, high-density, and ordered nanostructures in conjugated polymer poly(3-hexylthiophene) or P3HT, and also to simultaneously control 3D chain alignment within these P3HT nanostructures. Out-of-plane and in-plane grazing incident X-ray diffraction were used to determine the chain orientation in the imprinted P3HT nanostructures, which shows a strong dependence on their geometry (gratings or pillars). Vertical chain alignment was observed in both nanogratings and nanopillars, indicating strong potential to improve charge transport and optical properties for solar cells in comparison to bulk heterojunction structure. For P3HT nanogratings, pi-pi stacking along the grating direction with an angular distribution of +/-20 degrees was found, which is favorable for OFETs. We propose the chain alignment is induced by the nanoconfinement during nanoimprinting via pi-pi interaction and hydrophobic interaction between polymer chain and mold surfaces.
