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Two of the main weaknesses of modern electric double‐layer capacitors are the rather limited ranges of operating voltage and temperature in which these devices do not suffer from the occurrence of irreversible decomposition processes. These parameters are strongly interconnected and lowering the operating voltage when increasing the temperature is unavoidable, so as to protect the electric double‐layer capacitor from damage. With the aim to maintain the operating voltage as high as possible at elevated temperatures, in this study, the application of ethyl isopropyl sulfone as an electrolyte solvent for electric double‐layer capacitors is presented. It is shown that ethyl isopropyl sulfone‐based electrolytes display excellent thermal and electrochemical stability enabling high capacitance retention after floating tests for 500 h at 60 and 80 °C, e.g. 68% at 3.4 V at 60 °C. A possible reason for the above‐average stability is that decomposition products of ethyl isopropyl sulfone can deposit on the electrode surface which may act as a passivation layer and prevent further degradation. [ABSTRACT FROM AUTHOR]

Artificial photosynthesis for hydrogen production is an important element in the search for green energy sources. The incorporation of photoactive units into mechanically stable 2D materials paves the way toward the realization of ultrathin membranes as mimics for leaves. Here we present and compare two concepts to introduce a photoactive RuII polypyridine complex into ≈1 nm thick carbon nanomembranes (CNMs) generated by low‐energy electron irradiation induced cross‐linking of aromatic self‐assembled monolayers. The photoactive units are either directly incorporated into the CNM scaffold or covalently grafted to its surface. We characterize RuII CNMs using X‐ray photoelectron, surface‐enhanced Raman, photothermal deflection spectroscopy, atomic force, scanning electron microscopy, and study their photoactivity in graphene field‐effect devices. Therewith, we explore the applicability of low‐energy electron irradiation of metal complexes for photosensitizer nanosheet formation. [ABSTRACT FROM AUTHOR]