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Single-entity electrochemistry allows for assessing electrocatalytic activities of individual material entities such as nanoparticles (NPs). Thus, it becomes possible to consider intrinsic electrochemical properties of nanocatalysts when researching how activity relates to physical and structural material properties. Conversely, conventional electrochemical techniques provide a normalized sum current referring to a huge ensemble of NPs constituting, along with additives (e.g., binders), a complete catalyst-coated electrode. Accordingly, recording electrocatalytic responses of single NPs avoids interferences of ensemble effects and reduces the complexity of electrocatalytic processes, thus enabling detailed description and modelling. Herein, we present insights into the oxygen evolution catalysis at individual cubic Co\(_3\)O\(_4\) NPs impacting microelectrodes of different support materials. Simulating diffusion at supported nanocubes, measured step current signals can be analyzed, providing edge lengths, corresponding size distributions, and interference-free turnover frequencies. The provided nano-impact investigation of (electro-)catalyst-support effects contradicts assumptions on a low number of highly active sites.

Metal‐rich chalcogenides composed of highly abundant elements recently emerged as promising catalysts for the electrocatalytic hydrogen evolution reaction (HER). Many of these materials benefit from a high intrinsic conductivity as compared to their chalcogen‐rich congeners, greatly reducing the necessity for conductive additives or sophisticated nanostructuring. Herein, we showcase the high potential of metal‐rich transition‐metal chalcogenides for the electrocatalytic hydrogen formation by summarizing the recent progress achieved with M\(_9\)S\(_8\) (pentlandite type) and M\(_3\)S\(_2\) (heazlewoodite type) based materials, which represent the most frequently applied compositions for this purpose. By a detailed electrochemical comparison of bulk as well as pellet electrodes of metal‐rich Fe\(_{4.5}\)Ni\(_{4.5}\)S\(_8\), we also aim at raising awareness in the community for the inherent differences in catalytic properties of the materials themselves and those of the fabricated electrodes, a point that is often disregarded in reports on HER‐catalyst systems.

Metal‐rich chalcogenides composed of highly abundant elements recently emerged as promising catalysts for the electrocatalytic hydrogen evolution reaction (HER). Many of these materials benefit from a high intrinsic conductivity as compared to their chalcogen‐rich congeners, greatly reducing the necessity for conductive additives or sophisticated nanostructuring. Herein, we showcase the high potential of metal‐rich transition‐metal chalcogenides for the electrocatalytic hydrogen formation by summarizing the recent progress achieved with M9S8 (pentlandite type) and M3S2 (heazlewoodite type) based materials, which represent the most frequently applied compositions for this purpose. By a detailed electrochemical comparison of bulk as well as pellet electrodes of metal‐rich Fe4.5Ni4.5S8, we also aim at raising awareness in the community for the inherent differences in catalytic properties of the materials themselves and those of the fabricated electrodes, a point that is often disregarded in reports on HER‐catalyst systems.