Single conical nanopores were functionalised layer by layer with weak polyelectrolytes. We studied their influence on the ionic diode properties We have considered different couples of polyelectrolytes: poly-l-lysine/poly(acrylic acid) and poly(ethyleneimine)/poly(acrylic acid) as well as the influence of cross-linking. The results show that the nanopores decorated with poly(ethyleneimine)/poly(acrylic acid) exhibit an interesting behavior. Indeed, at pH 3, the nanopore is open only at the low salt concentration, while at pH 7, it is already open. The nanopores functionalized with poly-l-lysine/poly(acrylic acid) do not show an inversion of ionic transport properties with the pH as expected. After cross-linked to prevent large conformational changes, the ionic diode properties are dependent on the pH.
The noble, metal-free materials capable of efficiently catalyzing water splitting reactions currently hold a great deal of promise. In this study, we reported the structure and electrochemical performance of new MoS2-based material synthesized with L-cysteine. For this, a facile one-pot hydrothermal process was developed and an array of densely packed nanoplatelet-shaped hybrid species directly on a conductive substrate were obtained. The crucial role of L-cysteine was determined by numerous methods on the structure and composition of the synthesized material and its activity and stability for hydrogen evolution reaction (HER) from the acidic water. A low Tafel slope of 32.6 mV dec−1, close to a Pt cathode, was registered for the first time. The unique HER performance at the surface of this hybrid material in comparison with recently reported MoS2-based electrocatalysts was attributed to the formation of more defective 1T, 2H-MoS2/MoOx, C nanostructures with the dominant 1T-MoS2 phase and thermally degraded cysteine residues entrapped. Numerous stacks of metallic (1T-MoS2 and MoO2) and semiconducting (2H-MoS2 and MoO3) fragments relayed the formation of highly active layered nanosheets possessing a low hydrogen adsorption free energy and much greater durability, whereas intercalated cysteine fragments had a low Tafel slope of the HER reaction. X-ray photoelectron spectroscopy, scanning electron microscopy, thermography with mass spectrometry, high-resolution transmission electron microscopy, Raman spectroscopy techniques, and linear sweep voltammetry were applied to verify our findings.
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.