Synthesis and Nanoscale Characterization of Hierarchically Assembled Molecular Nanosheets

Abstract

Chemical functionalization of molecular 2D materials toward the assembly of hierarchical functional nanostructures is of great importance for nanotechnology including areas like artificial photocatalytic systems, nanobiosensors, or ultrafiltration. To achieve the desired functionality of 2D materials, these need to be characterized down to the nanoscale. However, obtaining the respective chemical information is challenging and generally requires the application of complementary experimental techniques. Here, the synthesis and chemical characterization of hierarchically assembled molecular nanosheets based on ≈1 nm thin, molecular carbon nanomembrane (CNM) and covalently grafted, single‐molecule layer cobalt(III) catalysts for the light‐driven hydrogen evolution reaction (HER) is demonstrated. X‐ray photoelectron spectroscopy (XPS) and tip‐enhanced Raman spectroscopy (TERS) to access both the transversal and longitudinal chemical information of the synthesized nanosheets with nanometer resolution are employed. TERS and XPS data provide detailed information on the average and local surface distribution of the catalyst as well as mechanistic details of the grafting reaction. The proposed approach represents a general route toward a nanoscale structural analysis for a variety of molecular 2D materials—a rapidly growing materials class with broad prospects for fundamental science and applications.

An Algebraic Blueprint for Predicting Turnover Numbers and Endpoints in Photocatalysis

“…The authors have cited additional references within the Supporting Information. [39][40][41][42][43]…”

“…Experimental information about the measurements performed for this study, the written Python script, fit parameters for the different fit functions, a comparison of asymmetric sigmoidal and two‐phase exponential fit function for the CoBArF catalyst, and additional information about the exemplary catalytic systems are supplied as Supporting Information . The authors have cited additional references within the Supporting Information [39–43] …”

Screening Cobalt-based Catalysts on Multicomponent CdSe@CdS Nanorods for Photocatalytic Hydrogen Evolution in Aqueous Media

“…In the present study, we combined PDA-coated CdSe@CdS nanorods with a series of cobaloxime catalysts with proven catalytic activity for HER. − This approach overcomes the limitations of the Co-catalysts, such as their very low water-solubility, and demonstrates hydrogen evolution in aqueous media. ,− Our results pave the way for developing highly efficient and stable photocatalytic systems for sustainable hydrogen production. By integrating PDA-coated CdSe@CdS nanorods with cobaloxime catalysts, we address the challenges of both charge separation and efficient HER catalysis.…”

Macropolyhedral syn-B18H22, the “Forgotten” Isomer

“…Two of the largest known macropolyhedral boranes are the isomeric docosahydrooctadecaboranes B 18 H 22 . , They exhibit a unique molecular structure with two open faces and six acidic bridging hydrogen atoms (μ H -BB). − Their structural and chemical properties, together with their interaction with light, make B 18 H 22 a promising candidate for a wide range of applications, from energy storage, , semiconductor doping ,− to nano- and optoelectronic devices. − The molecular structure of B 18 H 22 can be viewed as two decaborane molecules condensed together, with each subcluster sharing atoms B(5) and B(6) in the decaborane numbering system, in common (Figure B,C). The isomer syn -B 18 H 22 on which this study focuses is a much less-studied (“forgotten”) system compared to its anti -B 18 H 22 isomer, and it has a 2-fold symmetry axis due to the fusion of two {B10} units sharing the B(5)–B(6) edge so that B(5)B(5′) and B(6)B(6′) (Figure B); in the anti -B 18 H 22 isomer, B(5)B(6′) and B(6)B(5′), which results in the inversion symmetry (Figure C). ,, What has stimulated most of the recent interest in anti -B 18 H 22 and its substituted derivatives has mainly been their luminescence properties. − Our interest in the “forgotten”, nonluminescent isomer, syn -B 18 H 22 , has been stimulated mainly by its unique geometry and size with respect to its use as constituents of purely borane, carbon-free self-assembled monolayers and its further use toward 2-dimensional membranes with thickness below 1 nm and with a 3D-aromatic character, as well as capping ligands of atomically precise metal nanoclusters, a newly emerging class of materials with adjustable geometry, size, and properties. , …”