Electrocatalytic oxidation of organic molecules, in particular the formic acid oxidation reaction (FAOR), is crucial for applications such as direct liquid fuel cells. As one of the effective catalysts, platinum (Pt) has been widely used as the electrocatalyst for these reactions in the laboratory; however, its utilization in practical FAOR is still limited due to insufficient activity. This study introduces a simple and rapid molecular modification method to improve the FAOR performance of Pt by chemically adsorbing thiol or thiophenol molecules. At an optimal surface coverage of 7.1%, the current density of FAOR on cysteamine-grafted Pt reached up to 24.76 mA cm–2, a 7.2-fold increase compared to that on pristine Pt. This increase is mainly attributed to the change in the electronic structure of the Pt surface and the charge transfer at the interface, which are induced by the cysteamine molecules. X-ray photoelectron spectroscopy and in situ Raman spectroscopy demonstrated that the adsorption of cysteamine molecules on the Pt surface improves the charge transfer on the Pt surface and the production of formic acid via the formate pathway. The mechanism of enhanced catalysis on Pt-Cysteamine is revealed by density functional theory calculations. Interestingly, various thiols and thiophenols were also proved to be effective in promoting the FAOR reaction, and this strategy could also be applied to improve the performance of many other reactions (such as, methanol oxidation reaction).
For nanocrystals (NCs) self-assembly, understanding the chemical and supramolecular interactions among building blocks is significant for both fundamental scientific interests and rational nanosuperstructure construction. However, it has remained an extreme challenge for many self-assembly systems due to the lack of appropriately quantitative approaches for the corresponding exploration. Herein, by combination of the proposed colorimetric method for cationic surfactant quantitation and all-atom simulations, we manage to present a clear chemical picture for the thiol molecules modulated self-assembly of gold nanorods (GNRs), one of the earliest and most convenient methods for the fabrication of freestanding GNR self-assemblies. It is revealed that the self-assembly of GNRs is driven by the hydrophobic effects of the alkyl chains of the modified cationic surfactants, as their bilayer structure is destroyed by the added thiol molecules. In other words, the actual roles of the thiol molecules for causing GNRs assembly are indirectly inductive effects instead of the previously believed direct electrostatic attraction and/or hydrogen-bond linking effects of the binding thiol molecules. Furthermore, the GNRs exhibit diameter-dependent assembly behaviors: thicker GNRs tend to adopt the end-to-end assembly mode, while thin ones prefer the side-by-side assembly mode, further demonstrating that hydrophobic effects among the build blocks are the driving force for the GNRs assembly.
Maleimide-functionalized poly(ester carbonate)s are synthesized by ring-opening copolymerization of furan–maleimide functionalized trimethylene carbonate (FMTMC) with L -lactide and a subsequent retro Diels-Alder reaction. The maleimide groups on poly(ester carbonate)s are amenable to Michael addition with thiol-containing molecules such as 3-mercapto-1-propanol, 2-aminoethanethiol hydrochloride, and mercaptoacetic acid under mild conditions, enabling the formation of biodegradable materials with various functional groups (e.g., hydroxyl, amine, and carboxyl). In particular, the maleimide-functionalized poly(ester carbonate) is clicked with a laminin-derived peptide CQAASIKVAV. In vitro culture of PC12 cells shows that the maleimide-functionalized polymers, especially the CQAASIKVAV-grafted one, could support cell proliferation and neurite outgrowth. The maleimide-functionalized poly(ester carbonate)s provide a versatile platform for diverse functionalization and have comprehensive potential in biomedical engineering.
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